Adding Zero
[Since 0.8.4] - [ -P Structures/AddZero ] - [ Online docs ]
Adding 0 is useless, as 0 is the neutral element for addition. Besides, when one of the operands is an integer, PHP silently triggers a cast to integer for the other operand.
This rule also report using + with variables, proeprties, etc. which triggers an automated conversion to integer.
It is recommended to make the cast explicit with (int) .
<?php
// Explicit cast
$a = (int) foo();
// Useless addition
$a = foo() + 0;
$a = 0 + foo();
// Also works with minus
$b = 0 - $c; // drop the 0, but keep the minus
$b = $c - 0; // drop the 0 and the minus
$a += 0;
$a -= 0;
$z = '12';
print +$z + 1;
?>
Ambiguous Array Index
[Since 0.8.4] - [ -P Arrays/AmbiguousKeys ] - [ Online docs ]
Indexes should not be defined with different types than int or string.
Array indices only accept integers and strings, so any other type of literal is reported. In fact, null is turned into an empty string, booleans are turned into an integer, and real numbers are truncated (not rounded).
<?php
$x = [ 1 => 1,
'1' => 2,
1.0 => 3,
true => 4];
// $x only contains one element : 1 => 4
// Still wrong, immediate typecast to 1
$x[1.0] = 5;
$x[true] = 6;
?>
They are indeed distinct, but may lead to confusion.
See also and array
Array Index
[Since 0.8.4] - [ -P Arrays/Arrayindex ] - [ Online docs ]
List of all indexes used in arrays.
<?php
// Index
$x['index'] = 1;
// in array creation
$a = array('index2' => 1);
$a2 = ['index3' => 2];
?>
Multidimensional Arrays
[Since 0.8.4] - [ -P Arrays/Multidimensional ] - [ Online docs ]
Multidimensional arrays are arrays of arrays. Each level of array is called a dimension. The number of dimensions is arbitrary, though it is recommende not to abuse it beyond 4.
See also Type array and Using Multidimensional Arrays in PHP
Multiple Index Definition
[Since 0.8.4] - [ -P Arrays/MultipleIdenticalKeys ] - [ Online docs ]
Indexes that are defined multiple times in the same array.
They are indeed overwriting each other. This is most probably a typo.
PHP Arrays Index
[Since 0.8.4] - [ -P Arrays/Phparrayindex ] - [ Online docs ]
List of indexes used when manipulating PHP arrays in the code. These indices usually carry semantic meanings, and should always be readable.
Classes Names
[Since 0.8.4] - [ -P Classes/Classnames ] - [ Online docs ]
List of all classes, as defined in the application.
<?php
// foo is in the list
class foo {}
// Anonymous classes are not in the list
$o = class { function foo(){} }
?>
See also and class
Constant Definition
[Since 0.8.4] - [ -P Classes/ConstantDefinition ] - [ Online docs ]
List of class constants being defined.
<?php
// traditional way of making constants
define('aConstant', 1);
// modern way of making constants
const anotherConstant = 2;
class foo {
// Not a constant, a class constant.
const aClassConstant = 3;
}
?>
See also PHP Constants and PHP OOP Constants
Empty Classes
[Since 0.8.4] - [ -P Classes/EmptyClass ] - [ Online docs ]
Classes that do no define anything at all : no property, method nor constant. This is possibly dead code.
Empty classes are sometimes used to group classes; an interface may be used here for the same purpose, without inserting an extra level in the class hierarchy.
<?php
//Empty class
class foo extends bar {}
//Not an empty class
class foo2 extends bar {
const FOO = 2;
}
//Not an empty class, as derived from Exception
class barException extends \Exception {}
?>
Classes that are directly derived from an exception are omitted.
See also and class
Magic Methods
[Since 0.8.4] - [ -P Classes/MagicMethod ] - [ Online docs ]
List of PHP magic methods being used. The magic methods are
__call(), __callStatic(), __get(), __set(), __isset(), __unset(), __sleep(), __wakeup(), __toString(), __invoke(), __set_state(), __clone() and __debugInfo().
__construct and __destruct are omitted here, as they are routinely used to create and destroy objects.
<?php
class foo{
// PHP Magic method, called when cloning an object.
function __clone() {}
}
?>
Forgotten Visibility
[Since 0.8.4] - [ -P Classes/NonPpp ] - [ Online docs ]
Some classes elements (property, method, constant) are missing their explicit visibility.
By default, it is public. It should at least be mentioned as public, or may be reviewed as protected or private.
Class constants support also visibility since PHP 7.1.
final, static and abstract are not counted as visibility. Only public, private and protected. The PHP 4 var keyword is counted as undefined.
Traits, classes and interfaces are checked.
<?php
// Explicit visibility
class X {
protected sconst NO_VISIBILITY_CONST = 1; // For PHP 7.2 and later
private $noVisibilityProperty = 2;
public function Method() {}
}
// Missing visibility
class X {
const NO_VISIBILITY_CONST = 1; // For PHP 7.2 and later
var $noVisibilityProperty = 2; // Only with var
function NoVisibilityForMethod() {}
}
?>
See also Visibility and Understanding The Concept Of Visibility In Object Oriented PHP
Non Static Methods Called In A Static
[Since 0.8.4] - [ -P Classes/NonStaticMethodsCalledStatic ] - [ Online docs ]
Static methods have to be declared as such (using the static keyword). Then, one may call them without instantiating the object.
PHP 7.0, and more recent versions, yield a deprecated error : Non-static method A::B() should not be called statically .
PHP 5 and older doesn't check that a method is static or not : at any point, the code may call one method statically.
<?php
class x {
static public function sm( ) { echo __METHOD__.\n; }
public public sm( ) { echo __METHOD__.\n; }
}
x::sm( ); // echo x::sm
// Dynamic call
['x', 'sm']();
[\x::class, 'sm']();
$s = 'x::sm';
$s();
?>
It is a bad idea to call non-static method statically. Such method may make use of special
variable $this, which will be undefined. PHP will not check those calls at compile time,
nor at running time.
It is recommended to update this situation : make the method actually static, or use it only
in object context.
Note that this analysis reports all static method call made on a non-static method,
even within the same class or class hierarchy. PHP silently accepts static call to any
in-family method.
<?php
class x {
public function foo( ) { self::bar() }
public function bar( ) { echo __METHOD__.\n; }
}
?>
See also and Static Keyword
Old Style Constructor
[Since 0.8.4] - [ -P Classes/OldStyleConstructor ] - [ Online docs ]
PHP classes used to have the method bearing the same name as the class acts as the constructor. That was PHP 4, and early PHP 5.
The manual issues a warning about this syntax : Old style constructors are DEPRECATED in PHP 7.0, and will be removed in a future version. You should always use __construct() in new code.
<?php
namespace {
// Global namespace is important
class foo {
function foo() {
// This acts as the old-style constructor, and is reported by PHP
}
}
class bar {
function __construct() { }
function bar() {
// This doesn't act as constructor, as bar has a __construct() method
}
}
}
namespace Foo\Bar{
class foo {
function foo() {
// This doesn't act as constructor, as bar is not in the global namespace
}
}
}
?>
This is no more the case in PHP 5, which relies on __construct() to do so. Having this old style constructor may bring in confusion, unless you are also supporting old time PHP 4.
Note that classes with methods bearing the class name, but inside a namespace are not following this convention, as this is not breaking backward compatibility. Those are excluded from the analyze.
See also and Constructors and Destructors
Static Methods
[Since 0.8.4] - [ -P Classes/StaticMethods ] - [ Online docs ]
List of all static methods.
<?php
class foo {
static public function staticMethod() {
}
public function notStaticMethod() {
}
private function method() {
// This is not a property
new static();
}
}
?>
Static Methods Called From Object
[Since 0.8.4] - [ -P Classes/StaticMethodsCalledFromObject ] - [ Online docs ]
Static methods may be called without instantiating an object. As such, they never interact with the special variable '$this', as they do not depend on object existence.
Besides this, static methods are normal methods that may be called directly from object context, to perform some utility task.
To maintain code readability, it is recommended to call static method in a static way, rather than within object context.
<?php
class x {
static function y( ) {}
}
$z = new x( );
$z->y( ); // Readability : no one knows it is a static call
x::y( ); // Readability : here we know
?>
Static Properties
[Since 0.8.4] - [ -P Classes/StaticProperties ] - [ Online docs ]
List of all static properties.
<?php
class foo {
static public $staticProperty = 1;
public $notStaticProperty = 2;
private function method() {
// This is not a property
new static();
}
}
function bar() {
// This is not a static property
static $staticVariable;
//....
}
?>
Constants Usage
[Since 0.8.4] - [ -P Constants/ConstantUsage ] - [ Online docs ]
List of constants being used.
<?php
const MY_CONST = 'Hello';
// PHP_EOL (native PHP Constant)
// MY_CONST (custom constant)
echo PHP_EOL . MY_CONST;
?>
Magic Constant Usage
[Since 0.8.4] - [ -P Constants/MagicConstantUsage ] - [ Online docs ]
There are eight magical constants that change depending on where they are used. For example, the value of __LINE__ depends on the line that it's used on in your script. These special constants are case-insensitive.
+ __LINE__
+ __FILE__
+ __DIR__
+ __FUNCTION__
+ __CLASS__
+ __TRAIT__
+ __METHOD__
+ __NAMESPACE__
<?php
echo 'This code is in file '__FILE__.', line '.__LINE__;
?>
See also Magic Constants and
PHP Constant Usage
[Since 0.8.4] - [ -P Constants/PhpConstantUsage ] - [ Online docs ]
List of PHP constants being used.
<?php
const MY_CONST = 'Hello';
// PHP_EOL (native PHP Constant)
// MY_CONST (custom constant, not reported)
echo PHP_EOL . MY_CONST;
?>
See also and Predefined Constants
Defined Exceptions
[Since 0.8.4] - [ -P Exceptions/DefinedExceptions ] - [ Online docs ]
This is the list of defined exceptions.
<?php
class myException extends \Exception {}
// A defined exception
throw new myException();
// not a defined exception : it is already defined.
throw new \RuntimeException();
?>
See also Predefined Exceptions and Exceptions
Thrown Exceptions
[Since 0.8.4] - [ -P Exceptions/ThrownExceptions ] - [ Online docs ]
This rules reports the usage of the throw keyword. This means exceptions were raised.
See also and Exceptions
ext/apc
[Since 0.8.4] - [ -P Extensions/Extapc ] - [ Online docs ]
Extension Alternative PHP Cache.
The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.
This extension is considered unmaintained and dead.
<?php
$bar = 'BAR';
apc_add('foo', $bar);
var_dump(apc_fetch('foo'));
echo PHP_EOL;
$bar = 'NEVER GETS SET';
apc_add('foo', $bar);
var_dump(apc_fetch('foo'));
echo PHP_EOL;
?>
See also and Alternative PHP Cache
ext/bcmath
[Since 0.8.4] - [ -P Extensions/Extbcmath ] - [ Online docs ]
Extension BC Math.
For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision up to 2147483647-1 (or 0x7FFFFFFF-1 ) decimals, represented as strings.
<?php
echo bcpow('2', '123');
//10633823966279326983230456482242756608
echo 2**123;
//1.0633823966279E+37
?>
See also and BC Math Functions
ext/bzip2
[Since 0.8.4] - [ -P Extensions/Extbzip2 ] - [ Online docs ]
Extension ext/bzip2.
Bzip2 Functions for PHP.
<?php
$file = '/tmp/foo.bz2';
$bz = bzopen($file, 'r') or die('Couldn\'t open $file for reading');
bzclose($bz);
?>
See also Bzip2 Functions and bzip2
ext/calendar
[Since 0.8.4] - [ -P Extensions/Extcalendar ] - [ Online docs ]
Extension ext/calendar.
The calendar extension presents a series of functions to simplify converting between different calendar formats.
<?php
$number = cal_days_in_month(CAL_GREGORIAN, 8, 2003); // 31
echo "There were {$number} days in August 2003";
?>
See also and Calendar Functions
ext/crypto
[Since 0.8.4] - [ -P Extensions/Extcrypto ] - [ Online docs ]
Extension ext/crypto (PECL).
Objective PHP binding of OpenSSL Crypto library.
<?php
use Crypto\Cipher;
use Crypto\AlgorihtmException;
$algorithm = 'aes-256-cbc';
if (!Cipher::hasAlgorithm($algorithm)) {
die('Algorithm $algorithm not found' . PHP_EOL);
}
try {
$cipher = new Cipher($algorithm);
// Algorithm method for retrieving algorithm
echo 'Algorithm: ' . $cipher->getAlgorithmName() . PHP_EOL;
// Params
$key_len = $cipher->getKeyLength();
$iv_len = $cipher->getIVLength();
echo 'Key length: ' . $key_len . PHP_EOL;
echo 'IV length: ' . $iv_len . PHP_EOL;
echo 'Block size: ' . $cipher->getBlockSize() . PHP_EOL;
// This is just for this example. You should never use such key and IV!
$key = str_repeat('x', $key_len);
$iv = str_repeat('i', $iv_len);
// Test data
$data1 = 'Test';
$data2 = 'Data';
$data = $data1 . $data2;
// Simple encryption
$sim_ct = $cipher->encrypt($data, $key, $iv);
// init/update/finish encryption
$cipher->encryptInit($key, $iv);
$iuf_ct = $cipher->encryptUpdate($data1);
$iuf_ct .= $cipher->encryptUpdate($data2);
$iuf_ct .= $cipher->encryptFinish();
// Raw data output (used base64 format for printing)
echo 'Ciphertext (sim): ' . base64_encode($sim_ct) . PHP_EOL;
echo 'Ciphertext (iuf): ' . base64_encode($iuf_ct) . PHP_EOL;
// $iuf_out == $sim_out
$ct = $sim_ct;
// Another way how to create a new cipher object (using the same algorithm and mode)
$cipher = Cipher::aes(Cipher::MODE_CBC, 256);
// Simple decryption
$sim_text = $cipher->decrypt($ct, $key, $iv);
// init/update/finish decryption
$cipher->decryptInit($key, $iv);
$iuf_text = $cipher->decryptUpdate($ct);
$iuf_text .= $cipher->decryptFinish();
// Raw data output ($iuf_out == $sim_out)
echo 'Text (sim): ' . $sim_text . PHP_EOL;
echo 'Text (iuf): ' . $iuf_text . PHP_EOL;
}
catch (AlgorithmException $e) {
echo $e->getMessage() . PHP_EOL;
}
?>
See also pecl crypto and php-crypto
ext/ctype
[Since 0.8.4] - [ -P Extensions/Extctype ] - [ Online docs ]
Extension ext/ctype.
Ext/ctype checks whether a character or string falls into a certain character class according to the current locale.
<?php
$strings = array('AbCd1zyZ9', 'foo!#$bar');
foreach ($strings as $testcase) {
if (ctype_alnum($testcase)) {
echo "The string $testcase consists of all letters or digits.\n";
} else {
echo "The string $testcase does not consist of all letters or digits.\n";
}
}
?>
See also and Ctype functions
ext/curl
[Since 0.8.4] - [ -P Extensions/Extcurl ] - [ Online docs ]
Extension curl.
PHP supports libcurl, a library created by Daniel Stenberg. It allows the connection and communication to many different types of servers with many different types of protocols.
<?php
$ch = curl_init("http://www.example.com/");
$fp = fopen("example_homepage.txt", "w");
curl_setopt($ch, CURLOPT_FILE, $fp);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_exec($ch);
curl_close($ch);
fclose($fp);
?>
See also Curl for PHP and curl
ext/date
[Since 0.8.4] - [ -P Extensions/Extdate ] - [ Online docs ]
Extension ext/date.
These functions allows the manipulation of date and time from the server where the PHP scripts are running.
<?php
$dt = new DateTime('2015-11-01 00:00:00', new DateTimeZone('America/New_York'));
echo 'Start: ', $dt->format('Y-m-d H:i:s P'), PHP_EOL;
$dt->add(new DateInterval('PT3H'));
echo 'End: ', $dt->format('Y-m-d H:i:s P'), PHP_EOL;
?>
See also and Date and Time
ext/dba
[Since 0.8.4] - [ -P Extensions/Extdba ] - [ Online docs ]
Extension ext/dba.
These functions build the foundation for accessing Berkeley DB style databases.
<?php
$id = dba_open('/tmp/test.db', 'n', 'db2');
if (!$id) {
echo 'dba_open failed'.PHP_EOL;
exit;
}
dba_replace('key', 'This is an example!', $id);
if (dba_exists('key', $id)) {
echo dba_fetch('key', $id);
dba_delete('key', $id);
}
dba_close($id);
?>
See also and Database (dbm-style) Abstraction Layer
ext/dom
[Since 0.8.4] - [ -P Extensions/Extdom ] - [ Online docs ]
Extension Document Object Model.
The DOM extension allows the manipulation of XML documents through the DOM API with PHP.
<?php
$dom = new DOMDocument('1.0', 'utf-8');
$element = $dom->createElement('test', 'This is the root element!');
// We insert the new element as root (child of the document)
$dom->appendChild($element);
echo $dom->saveXML();
?>
See also and Document Object Model
ext/enchant
[Since 0.8.4] - [ -P Extensions/Extenchant ] - [ Online docs ]
Extension Enchant.
Enchant is the PHP binding for the Enchant spelling library. Enchant steps in to provide uniformity and conformity on top of all spelling libraries, and implement certain features that may be lacking in any individual provider library.
<?php
$tag = 'en_US';
$r = enchant_broker_init();
$bprovides = enchant_broker_describe($r);
echo 'Current broker provides the following backend(s):'.PHP_EOL;
print_r($bprovides);
$dicts = enchant_broker_list_dicts($r);
print_r($dicts);
if (enchant_broker_dict_exists($r,$tag)) {
$d = enchant_broker_request_dict($r, $tag);
$dprovides = enchant_dict_describe($d);
echo 'dictionary $tag provides:'.PHP_EOL;
$wordcorrect = enchant_dict_check($d, 'soong');
print_r($dprovides);
if (!$wordcorrect) {
$suggs = enchant_dict_suggest($d, 'soong');
echo 'Suggestions for "soong":';
print_r($suggs);
}
enchant_broker_free_dict($d);
} else {
}
enchant_broker_free($r);
?>
See also Enchant spelling library and Enchant
ext/exif
[Since 0.8.4] - [ -P Extensions/Extexif ] - [ Online docs ]
Extension EXIF : Exchangeable image file format.
The EXIF extension manipulates image meta data.
<?php
echo 'test1.jpg:<br />';
$exif = exif_read_data('tests/test1.jpg', 'IFD0');
echo $exif===false ? 'No header data found.<br />' : 'Image contains headers<br />';
$exif = exif_read_data('tests/test2.jpg', 0, true);
echo 'test2.jpg:<br />';
foreach ($exif as $key => $section) {
foreach ($section as $name => $val) {
echo $key.$name.': '.$val.'<br />';
}
}
?>
See also and Exchangeable image information
ext/fileinfo
[Since 0.8.4] - [ -P Extensions/Extfileinfo ] - [ Online docs ]
Extension ext/fileinfo.
This module guesses the content type and encoding of a file by looking for certain magic byte sequences at specific positions within the file.
<?php
$finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
foreach (glob('*') as $filename) {
echo finfo_file($finfo, $filename) . PHP_EOL;
}
finfo_close($finfo);
?>
See also and Filinfo
ext/filter
[Since 0.8.4] - [ -P Extensions/Extfilter ] - [ Online docs ]
Extension filter.
This extension filters data by either validating or sanitizing it.
<?php
$email_a = 'joe@example.com';
$email_b = 'bogus';
if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
echo 'This ($email_a) email address is considered valid.'.PHP_EOL;
}
if (filter_var($email_b, FILTER_VALIDATE_EMAIL)) {
echo 'This ($email_b) email address is considered valid.'.PHP_EOL;
} else {
echo 'This ($email_b) email address is considered invalid.'.PHP_EOL;
}
?>
See also and Data filtering
ext/ftp
[Since 0.8.4] - [ -P Extensions/Extftp ] - [ Online docs ]
Extension FTP.
The functions in this extension implement client access to files servers speaking the File Transfer Protocol (FTP) as defined in RFC 959.
<?php
// set up basic connection
$conn_id = ftp_connect($ftp_server);
// login with username and password
$login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
// check connection
if ((!$conn_id) || (!$login_result)) {
echo 'FTP connection has failed!';
echo 'Attempted to connect to $ftp_server for user $ftp_user_name';
exit;
} else {
echo 'Connected to $ftp_server, for user $ftp_user_name';
}
// upload the file
$upload = ftp_put($conn_id, $destination_file, $source_file, FTP_BINARY);
// check upload status
if (!$upload) {
echo 'FTP upload has failed!';
} else {
echo 'Uploaded $source_file to $ftp_server as $destination_file';
}
// close the FTP stream
ftp_close($conn_id);
?>
See also and FTP
ext/gd
[Since 0.8.4] - [ -P Extensions/Extgd ] - [ Online docs ]
Extension GD for PHP.
This extension allows PHP to create and manipulate image files in a variety of different image formats, including GIF, PNG, JPEG, WBMP, and XPM.
<?php
header("Content-type: image/png");
$string = $_GET['text'];
$im = imagecreatefrompng("images/button1.png");
$orange = imagecolorallocate($im, 220, 210, 60);
$px = (imagesx($im) - 7.5 * strlen($string)) / 2;
imagestring($im, 3, $px, 9, $string, $orange);
imagepng($im);
imagedestroy($im);
?>
See also and Image Processing and GD
ext/gmp
[Since 0.8.4] - [ -P Extensions/Extgmp ] - [ Online docs ]
Extension ext/gmp.
These functions allow for arbitrary-length integers to be worked with using the GNU MP library.
<?php
$pow1 = gmp_pow('2', 131);
echo gmp_strval($pow1) . PHP_EOL;
$pow2 = gmp_pow('0', 0);
echo gmp_strval($pow2) . PHP_EOL;
$pow3 = gmp_pow('2', -1); // Negative exp, generates warning
echo gmp_strval($pow3) . PHP_EOL;
?>
See also GMP and GNU MP library
ext/gnupgp
[Since 0.8.4] - [ -P Extensions/Extgnupg ] - [ Online docs ]
Extension GnuPG.
This module allows you to interact with gnupg.
<?php
// init gnupg
$res = gnupg_init();
// not really needed. Clearsign is default
gnupg_setsignmode($res,GNUPG_SIG_MODE_CLEAR);
// add key with passphrase 'test' for signing
gnupg_addsignkey($res,"8660281B6051D071D94B5B230549F9DC851566DC","test");
// sign
$signed = gnupg_sign($res,"just a test");
echo $signed;
?>
See also Gnupg Function for PHP and GnuPG
ext/hash
[Since 0.8.4] - [ -P Extensions/Exthash ] - [ Online docs ]
Extension for HASH Message Digest Framework.
Message Digest (hash) engine. Allows direct or incremental processing of arbitrary length messages using a variety of hashing algorithms.
<?php
/* Create a file to calculate hash of */
file_put_contents('example.txt', 'The quick brown fox jumped over the lazy dog.');
echo hash_file('md5', 'example.txt');
?>
See also and HASH Message Digest Framework
ext/iconv
[Since 0.8.4] - [ -P Extensions/Exticonv ] - [ Online docs ]
Extension ext/iconv.
With this module, you can turn a string represented by a local character set into the one represented by another character set, which may be the Unicode character set.
<?php
$text = "This is the Euro symbol '€'.";
echo 'Original : ', $text, PHP_EOL;
echo 'TRANSLIT : ', iconv("UTF-8", "ISO-8859-1//TRANSLIT", $text), PHP_EOL;
echo 'IGNORE : ', iconv("UTF-8", "ISO-8859-1//IGNORE", $text), PHP_EOL;
echo 'Plain : ', iconv("UTF-8", "ISO-8859-1", $text), PHP_EOL;
?>
See also Iconv and libiconv
ext/json
[Since 0.8.4] - [ -P Extensions/Extjson ] - [ Online docs ]
Extension JSON.
This extension implements the JavaScript Object Notation (JSON) data-interchange format. PHP implements a superset of JSON as specified in the original RFC 7159.
<?php
$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
echo json_encode($arr);
?>
See also JavaScript Object Notation and JSON
ext/ldap
[Since 0.8.4] - [ -P Extensions/Extldap ] - [ Online docs ]
Extension ext/ldap.
LDAP is the Lightweight Directory Access Protocol, and is a protocol used to access 'Directory Servers'. The Directory is a special kind of database that holds information in a tree structure.
<?php
// basic sequence with LDAP is connect, bind, search, interpret search
// result, close connection
echo '<h3>LDAP query test</h3>';
echo 'Connecting ...';
$ds=ldap_connect('localhost'); // must be a valid LDAP server!
echo 'connect result is ' . $ds . '<br />';
if ($ds) {
echo 'Binding ...';
$r=ldap_bind($ds); // this is an 'anonymous' bind, typically
// read-only access
echo 'Bind result is ' . $r . '<br />';
echo 'Searching for (sn=S*) ...';
// Search surname entry
$sr=ldap_search($ds, 'o=My Company, c=US', 'sn=S*');
echo 'Search result is ' . $sr . '<br />';
echo 'Number of entries returned is ' . ldap_count_entries($ds, $sr) . '<br />';
echo 'Getting entries ...<p>';
$info = ldap_get_entries($ds, $sr);
echo 'Data for ' . $info['count'] . ' items returned:<p>';
for ($i=0; $i<$info['count']; $i++) {
echo 'dn is: ' . $info[$i]['dn'] . '<br />';
echo 'first cn entry is: ' . $info[$i]['cn'][0] . '<br />';
echo 'first email entry is: ' . $info[$i]['mail'][0] . '<br /><hr />';
}
echo 'Closing connection';
ldap_close($ds);
} else {
echo '<h4>Unable to connect to LDAP server</h4>';
}
?>
See also and Lightweight Directory Access Protocol
ext/libxml
[Since 0.8.4] - [ -P Extensions/Extlibxml ] - [ Online docs ]
Extension libxml.
These functions/constants are available as of PHP 5.1.0, and the following core extensions rely on this libxml extension: DOM, libxml, SimpleXML, SOAP, WDDX, XSL, XML, XMLReader, XMLRPC and XMLWriter.
<?php
// $xmlstr is a string, containing a XML document.
$doc = simplexml_load_string($xmlstr);
$xml = explode(PHP_EOL, $xmlstr);
if ($doc === false) {
$errors = libxml_get_errors();
foreach ($errors as $error) {
echo display_xml_error($error, $xml);
}
libxml_clear_errors();
}
function display_xml_error($error, $xml)
{
$return = $xml[$error->line - 1] . PHP_EOL;
$return .= str_repeat('-', $error->column) . '^'.PHP_EOL;
switch ($error->level) {
case LIBXML_ERR_WARNING:
$return .= 'Warning ',$error->code.': ';
break;
case LIBXML_ERR_ERROR:
$return .= 'Error '.$error->code.': ';
break;
case LIBXML_ERR_FATAL:
$return .= 'Fatal Error '.$error->code.': ';
break;
}
$return .= trim($error->message) .
PHP_EOL.' Line: '.$error->line .
PHP_EOL.' Column: '.$error->column;
if ($error->file) {
$return .= "\n File: $error->file";
}
return $return.PHP_EOL.PHP_EOL.'--------------------------------------------'.PHP_EOL.PHP_EOL;
}
?>
See also and libxml
ext/mbstring
[Since 0.8.4] - [ -P Extensions/Extmbstring ] - [ Online docs ]
Extension ext/mbstring .
mbstring provides multibyte specific string functions that help you deal with multibyte encodings in PHP.
<?php
/* Convert internal character encoding to SJIS */
$str = mb_convert_encoding($str, "SJIS");
/* Convert EUC-JP to UTF-7 */
$str = mb_convert_encoding($str, "UTF-7", "EUC-JP");
/* Auto detect encoding from JIS, eucjp-win, sjis-win, then convert str to UCS-2LE */
$str = mb_convert_encoding($str, "UCS-2LE", "JIS, eucjp-win, sjis-win");
/* "auto" is expanded to "ASCII,JIS,UTF-8,EUC-JP,SJIS" */
$str = mb_convert_encoding($str, "EUC-JP", "auto");
?>
See also and Mbstring
ext/mcrypt
[Since 0.8.4] - [ -P Extensions/Extmcrypt ] - [ Online docs ]
Extension for mcrypt.
This extension has been deprecated as of PHP 7.1.0 and moved to PECL as of PHP 7.2.0.
This is an interface to the mcrypt library, which supports a wide variety of block algorithms such as DES, TripleDES, Blowfish (default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and GOST in CBC, OFB, CFB and ECB cipher modes. Additionally, it supports RC6 and IDEA which are considered 'non-free'. CFB/OFB are 8bit by default.
<?php
# --- ENCRYPTION ---
# the key should be random binary, use scrypt, bcrypt or PBKDF2 to
# convert a string into a key
# key is specified using hexadecimal
$key = pack('H*', 'bcb04b7e103a0cd8b54763051cef08bc55abe029fdebae5e1d417e2ffb2a00a3');
# show key size use either 16, 24 or 32 byte keys for AES-128, 192
# and 256 respectively
$key_size = strlen($key);
echo 'Key size: ' . $key_size . PHP_EOL;
$plaintext = 'This string was AES-256 / CBC / ZeroBytePadding encrypted.';
# create a random IV to use with CBC encoding
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
# creates a cipher text compatible with AES (Rijndael block size = 128)
# to keep the text confidential
# only suitable for encoded input that never ends with value 00h
# (because of default zero padding)
$ciphertext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key,
$plaintext, MCRYPT_MODE_CBC, $iv);
# prepend the IV for it to be available for decryption
$ciphertext = $iv . $ciphertext;
# encode the resulting cipher text so it can be represented by a string
$ciphertext_base64 = base64_encode($ciphertext);
echo $ciphertext_base64 . PHP_EOL;
# === WARNING ===
# Resulting cipher text has no integrity or authenticity added
# and is not protected against padding oracle attacks.
# --- DECRYPTION ---
$ciphertext_dec = base64_decode($ciphertext_base64);
# retrieves the IV, iv_size should be created using mcrypt_get_iv_size()
$iv_dec = substr($ciphertext_dec, 0, $iv_size);
# retrieves the cipher text (everything except the $iv_size in the front)
$ciphertext_dec = substr($ciphertext_dec, $iv_size);
# may remove 00h valued characters from end of plain text
$plaintext_dec = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key,
$ciphertext_dec, MCRYPT_MODE_CBC, $iv_dec);
echo $plaintext_dec . PHP_EOL;
?>
See also extension mcrypt and mcrypt
ext/mongo
[Since 0.8.4] - [ -P Extensions/Extmongo ] - [ Online docs ]
Extension MongoDB driver (legacy).
<?php
// connect
$m = new MongoClient();
// select a database
$db = $m->comedy;
// select a collection (analogous to a relational database\'s table)
$collection = $db->cartoons;
// add a record
$document = array( 'title' => 'Calvin and Hobbes', 'author' => 'Bill Watterson' );
$collection->insert($document);
// add another record, with a different 'shape'
$document = array( 'title' => 'XKCD', 'online' => true );
$collection->insert($document);
// find everything in the collection
$cursor = $collection->find();
// iterate through the results
foreach ($cursor as $document) {
echo $document['title'] . PHP_EOL;
}
?>
Note : this is not the MongoDB driver. This is the legacy extension.
See also ext/mongo manual and MongdDb
ext/mssql
[Since 0.8.4] - [ -P Extensions/Extmssql ] - [ Online docs ]
Extension MSSQL, Microsoft SQL Server.
These functions allow you to access MS SQL Server database.
<?php
// Connect to MSSQL
$link = mssql_connect('KALLESPC\SQLEXPRESS', 'sa', 'phpfi');
if (!$link || !mssql_select_db('php', $link)) {
die('Unable to connect or select database!');
}
// Do a simple query, select the version of
// MSSQL and print it.
$version = mssql_query('SELECT @@VERSION');
$row = mssql_fetch_array($version);
echo $row[0];
// Clean up
mssql_free_result($version);
?>
See also Microsoft SQL Server and Microsoft PHP Driver for SQL Server
ext/mysql
[Since 0.8.4] - [ -P Extensions/Extmysql ] - [ Online docs ]
Extension for MySQL (Original MySQL API).
This extension is deprecated as of PHP 5.5.0, and has been removed as of PHP 7.0.0. Instead, either the mysqli or PDO_MySQL extension should be used. See also the MySQL API Overview for further help while choosing a MySQL API.
<?php
$result = mysql_query('SELECT * WHERE 1=1');
if (!$result) {
die('Invalid query: ' . mysql_error());
}
?>
See also Original MySQL API and MySQL
ext/mysqli
[Since 0.8.4] - [ -P Extensions/Extmysqli ] - [ Online docs ]
Extension mysqli for MySQL.
The mysqli extension allows you to access the functionality provided by MySQL 4.1 and above.
<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'world');
/* check connection */
if (mysqli_connect_errno()) {
printf('Connect failed: %s\n', mysqli_connect_error());
exit();
}
$city = 'Amersfoort';
/* create a prepared statement */
if ($stmt = $mysqli->prepare('SELECT District FROM City WHERE Name=?')) {
/* bind parameters for markers */
$stmt->bind_param('s', $city);
/* execute query */
$stmt->execute();
/* bind result variables */
$stmt->bind_result($district);
/* fetch value */
$stmt->fetch();
printf('%s is in district %s\n', $city, $district);
/* close statement */
$stmt->close();
}
/* close connection */
$mysqli->close();
?>
See also MySQL Improved Extension, MySQL and Mariadb
ext/odbc
[Since 0.8.4] - [ -P Extensions/Extodbc ] - [ Online docs ]
Extension ODBC.
In addition to normal ODBC support, the Unified ODBC functions in PHP allow you to access several databases that have borrowed the semantics of the ODBC API to implement their own API. Instead of maintaining multiple database drivers that were all nearly identical, these drivers have been unified into a single set of ODBC functions.
<?php
$a = 1;
$b = 2;
$c = 3;
$stmt = odbc_prepare($conn, 'CALL myproc(?,?,?)');
$success = odbc_execute($stmt, array($a, $b, $c));
?>
See also ODBC (Unified), Unixodbc and IODBC
ext/openssl
[Since 0.8.4] - [ -P Extensions/Extopenssl ] - [ Online docs ]
Extension Openssl.
This extension binds functions of OpenSSL library for symmetric and asymmetric encryption and decryption, PBKDF2 , PKCS7 , PKCS12 , X509 and other cryptographic operations. In addition to that it provides implementation of TLS streams.
<?php
// $data and $signature are assumed to contain the data and the signature
// fetch public key from certificate and ready it
$pubkeyid = openssl_pkey_get_public("file://src/openssl-0.9.6/demos/sign/cert.pem");
// state whether signature is okay or not
$ok = openssl_verify($data, $signature, $pubkeyid);
if ($ok == 1) {
echo "good";
} elseif ($ok == 0) {
echo "bad";
} else {
echo "ugly, error checking signature";
}
// free the key from memory
openssl_free_key($pubkeyid);
?>
See also ext/OpenSSL and OpenSSL
ext/pcre
[Since 0.8.4] - [ -P Extensions/Extpcre ] - [ Online docs ]
Extension ext/pcre. PCRE stands for Perl Compatible Regular Expression. It is a standard PHP extension.
<?php
$zip_code = $_GET['zip'];
// Canadian Zip code H2M 3J1
$zip_ca = '/^([a-zA-Z]\d[a-zA-Z])\ {0,1}(\d[a-zA-Z]\d)$/';
// French Zip code 75017
$zip_fr = '/^\d{5}$/';
// Chinese Zip code 590615
$zip_cn = '/^\d{6}$/';
var_dump(preg_match($_GET['zip']));
?>
See also and Regular Expressions (Perl-Compatible)
ext/pdo
[Since 0.8.4] - [ -P Extensions/Extpdo ] - [ Online docs ]
Generic extension PDO.
The PHP Data Objects (PDO) extension defines a lightweight, consistent interface for accessing databases in PHP.
<?php
/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
FROM fruit
WHERE calories < :calories AND colour = :colour';
$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));
$red = $sth->fetchAll();
$sth->execute(array(':calories' => 175, ':colour' => 'yellow'));
$yellow = $sth->fetchAll();
?>
See also and PHP Data Object
ext/pgsql
[Since 0.8.4] - [ -P Extensions/Extpgsql ] - [ Online docs ]
Extension PostGreSQL.
PostgreSQL is an open source descendant of this original Berkeley code. It provides SQL92/SQL99 language support, transactions, referential integrity, stored procedures and type extensibility.
<?php
// Connect to a database named 'mary'
$dbconn = pg_connect('dbname=mary');
// Prepare a query for execution
$result = pg_prepare($dbconn, 'my_query', 'SELECT * FROM shops WHERE name = $1');
// Execute the prepared query. Note that it is not necessary to escape
// the string 'Joe's Widgets' in any way
$result = pg_execute($dbconn, 'my_query', array('Joe\'s Widgets'));
// Execute the same prepared query, this time with a different parameter
$result = pg_execute($dbconn, 'my_query', array('Clothes Clothes Clothes'));
?>
See also PostgreSQL and PostgreSQL: The world's most advanced open source database
ext/phar
[Since 0.8.4] - [ -P Extensions/Extphar ] - [ Online docs ]
Extension phar.
The phar extension provides a way to put entire PHP applications into a single file called a phar (PHP Archive) for easy distribution and installation.
<?php
try {
$p = new Phar('/path/to/my.phar', 0, 'my.phar');
$p['myfile.txt'] = 'hi';
$file = $p['myfile.txt'];
var_dump($file->isCompressed(Phar::BZ2));
$p['myfile.txt']->compress(Phar::BZ2);
var_dump($file->isCompressed(Phar::BZ2));
} catch (Exception $e) {
echo 'Create/modify operations on my.phar failed: ', $e;
}
?>
See also and phar
ext/posix
[Since 0.8.4] - [ -P Extensions/Extposix ] - [ Online docs ]
Extension POSIX.
Ext/posix contains an interface to those functions defined in the IEEE 1003.1 (POSIX.1) standards document which are not accessible through other means.
<?php
posix_kill(999459,SIGKILL);
echo 'Your error returned was '.posix_get_last_error(); //Your error was ___
?>
See also and 1003.1-2008 - IEEE Standard for Information Technology - Portable Operating System Interface (POSIX(R))
ext/readline
[Since 0.8.4] - [ -P Extensions/Extreadline ] - [ Online docs ]
Extension readline.
The readline functions implement an interface to the GNU Readline library. These are functions that provide editable command lines.
<?php
//get 3 commands from user
for ($i=0; $i < 3; $i++) {
$line = readline("Command: ");
readline_add_history($line);
}
//dump history
print_r(readline_list_history());
//dump variables
print_r(readline_info());
?>
See also ext/readline and The GNU Readline Library
ext/reflection
[Since 0.8.4] - [ -P Extensions/Extreflection ] - [ Online docs ]
Extension Reflection.
PHP comes with a complete reflection API that adds the ability to reverse-engineer classes, interfaces, functions, methods and extensions. Additionally, the reflection API offers ways to retrieve doc comments for functions, classes and methods.
<?php
/**
* A simple counter
*
* @return int
*/
function counter1()
{
static $c = 0;
return ++$c;
}
/**
* Another simple counter
*
* @return int
*/
$counter2 = function()
{
static $d = 0;
return ++$d;
};
function dumpReflectionFunction($func)
{
// Print out basic information
printf(
PHP_EOL.'===> The %s function '%s''.PHP_EOL.
' declared in %s'.PHP_EOL.
' lines %d to %d'.PHP_EOL,
$func->isInternal() ? 'internal' : 'user-defined',
$func->getName(),
$func->getFileName(),
$func->getStartLine(),
$func->getEndline()
);
// Print documentation comment
printf('---> Documentation:'.PHP_EOL.' %s',PHP_EOL, var_export($func->getDocComment(), 1));
// Print static variables if existant
if ($statics = $func->getStaticVariables())
{
printf('---> Static variables: %s',PHP_EOL, var_export($statics, 1));
}
}
// Create an instance of the ReflectionFunction class
dumpReflectionFunction(new ReflectionFunction('counter1'));
dumpReflectionFunction(new ReflectionFunction($counter2));
?>
See also and Reflection
ext/sem
[Since 0.8.4] - [ -P Extensions/Extsem ] - [ Online docs ]
Extension Semaphore, Shared Memory and IPC.
This module provides wrappers for the System V IPC family of functions. It includes semaphores, shared memory and inter-process messaging (IPC).
<?php
$key = ftok(__FILE__,'a');
$semaphore = sem_get($key);
sem_acquire($semaphore);
sem_release($semaphore);
sem_remove($semaphore);
?>
See also and Semaphore, Shared Memory and IPC
ext/session
[Since 0.8.4] - [ -P Extensions/Extsession ] - [ Online docs ]
Extension ext/session.
Session support in PHP consists of a way to preserve certain data across subsequent accesses.
<?php
session_start();
if (!isset($_SESSION['count'])) {
$_SESSION['count'] = 0;
} else {
$_SESSION['count']++;
}
?>
See also and Session
ext/shmop
[Since 0.8.4] - [ -P Extensions/Extshmop ] - [ Online docs ]
Extension ext/shmop.
Shmop is an easy to use set of functions that allows PHP to read, write, create and delete Unix shared memory segments.
<?php
// Create a temporary file and return its path
$tmp = tempnam('/tmp', 'PHP');
// Get the file token key
$key = ftok($tmp, 'a');
// Attach the SHM resource, notice the cast afterwards
$id = shm_attach($key);
if ($id === false) {
die('Unable to create the shared memory segment');
}
// Cast to integer, since prior to PHP 5.3.0 the resource id
// is returned which can be exposed when casting a resource
// to an integer
$id = (integer) $id;
?>
See also and Semaphore, Shared Memory and IPC
ext/simplexml
[Since 0.8.4] - [ -P Extensions/Extsimplexml ] - [ Online docs ]
Extension SimpleXML .
The SimpleXML extension provides a very simple and easily usable toolset to convert XML to an object that can be processed with normal property selectors and array iterators.
<?php
$xml = <<<'XML'
<?xml version='1.0' standalone='yes' ? >
<movies>
<movie>
<title>PHP: Behind the Parser</title>
<characters>
<character>
<name>Ms. Coder</name>
<actor>Onlivia Actora</actor>
</character>
<character>
<name>Mr. Coder</name>
<actor>El ActÓr</actor>
</character>
</characters>
<plot>
So, this language. It's like, a programming language. Or is it a
scripting language? All is revealed in this thrilling horror spoof
of a documentary.
</plot>
<great-lines>
<line>PHP solves all my web problems</line>
</great-lines>
<rating type="thumbs">7</rating>
<rating type="stars">5</rating>
</movie>
</movies>
XML;
$movies = new SimpleXMLElement($xml);
echo $movies->movie[0]->plot;
?>
See also and SimpleXML
ext/snmp
[Since 0.8.4] - [ -P Extensions/Extsnmp ] - [ Online docs ]
Extension SNMP.
The SNMP extension provides a very simple and easily usable toolset for managing remote devices via the Simple Network Management Protocol.
<?php
$nameOfSecondInterface = snmp3_get('localhost', 'james', 'authPriv', 'SHA', 'secret007', 'AES', 'secret007', 'IF-MIB::ifName.2');
?>
See also Net SNMP and SNMP
ext/soap
[Since 0.8.4] - [ -P Extensions/Extsoap ] - [ Online docs ]
Extension SOAP.
The SOAP extension can be used to write SOAP Servers and Clients. It supports subsets of » SOAP 1.1, » SOAP 1.2 and » WSDL 1.1 specifications.
<?php
$client = new SoapClient("some.wsdl");
$client = new SoapClient("some.wsdl", array('soap_version' => SOAP_1_2));
$client = new SoapClient("some.wsdl", array('login' => "some_name",
'password' => "some_password"));
?>
See also SOAP and SOAP specifications
ext/sockets
[Since 0.8.4] - [ -P Extensions/Extsockets ] - [ Online docs ]
Extension socket.
The socket extension implements a low-level interface to the socket communication functions based on the popular BSD sockets, providing the possibility to act as a socket server as well as a client.
<?php
//Example #2 Socket example: Simple TCP/IP client
//From the PHP manual
error_reporting(E_ALL);
echo "<h2>TCP/IP Connection</h2>\n";
/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');
/* Get the IP address for the target host. */
$address = gethostbyname('www.example.com');
/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
echo 'socket_create() failed: reason: ' . socket_strerror(socket_last_error()) . PHP_EOL;
} else {
echo 'OK.'.PHP_EOL;
}
echo 'Attempting to connect to '$address' on port '$service_port'...';
$result = socket_connect($socket, $address, $service_port);
if ($result === false) {
echo 'socket_connect() failed.\nReason: ($result) ' . socket_strerror(socket_last_error($socket)) . '\n';
} else {
echo 'OK.'.PHP_EOL;
}
$in = ""HEAD / HTTP/1.1\r\n"";
$in .= ""Host: www.example.com\r\n"";
$in .= ""Connection: Close\r\n\r\n"";
$out = '';
echo 'Sending HTTP HEAD request...';
socket_write($socket, $in, strlen($in));
echo "OK.\n";
echo 'Reading response:\n\n';
while ($out = socket_read($socket, 2048)) {
echo $out;
}
echo 'Closing socket...';
socket_close($socket);
echo 'OK.\n\n';
?>
See also and Sockets
ext/spl
[Since 0.8.4] - [ -P Extensions/Extspl ] - [ Online docs ]
SPL extension.
The Standard PHP Library (SPL) is a collection of interfaces and classes that are meant to solve common problems.
<?php
// Example with FilesystemIterator
$files = new FilesystemIterator('/path/to/dir');
foreach($files as $file) {
echo $file->getFilename() . PHP_EOL;
}
?>
See also and Standard PHP Library (SPL)
ext/sqlite
[Since 0.11.3] - [ -P Extensions/Extsqlite ] - [ Online docs ]
Extension Sqlite 2.
Support for SQLite version 2 databases. The support for this version of Sqlite has ended. It is recommended to use SQLite3 .
<?php
if ($db = sqlite_open('mysqlitedb', 0666, $sqliteerror)) {
sqlite_query($db, 'CREATE TABLE foo (bar varchar(10))');
sqlite_query($db, 'INSERT INTO foo VALUES ("fnord")');
$result = sqlite_query($db, 'select bar from foo');
var_dump(sqlite_fetch_array($result));
} else {
die($sqliteerror);
}
?>
See also ext/sqlite and SQLite
ext/sqlite3
[Since 0.8.4] - [ -P Extensions/Extsqlite3 ] - [ Online docs ]
Extension Sqlite3.
Support for SQLite version 3 databases.
<?php
$db = new SQLite3('mysqlitedb.db');
$results = $db->query('SELECT bar FROM foo');
while ($row = $results->fetchArray()) {
var_dump($row);
}
?>
See also ext/sqlite3 and Sqlite
ext/ssh2
[Since 0.8.4] - [ -P Extensions/Extssh2 ] - [ Online docs ]
Extension ext/ssh2.
<?php
/* Notify the user if the server terminates the connection */
function my_ssh_disconnect($reason, $message, $language) {
printf("Server disconnected with reason code [%d] and message: %s\n",
$reason, $message);
}
$methods = array(
'kex' => 'diffie-hellman-group1-sha1',
'client_to_server' => array(
'crypt' => '3des-cbc',
'comp' => 'none'),
'server_to_client' => array(
'crypt' => 'aes256-cbc,aes192-cbc,aes128-cbc',
'comp' => 'none'));
$callbacks = array('disconnect' => 'my_ssh_disconnect');
$connection = ssh2_connect('shell.example.com', 22, $methods, $callbacks);
if (!$connection) die('Connection failed');
?>
See also SSH2 functions and ext/ssh2 on PECL
ext/standard
[Since 0.8.4] - [ -P Extensions/Extstandard ] - [ Online docs ]
Standards PHP functions.
This is not a real PHP extension : it covers the core functions.
<?php
/*
Our php.ini contains the following settings:
display_errors = On
register_globals = Off
post_max_size = 8M
*/
echo 'display_errors = ' . ini_get('display_errors') . PHP_EOL;
echo 'register_globals = ' . ini_get('register_globals') . PHP_EOL;
echo 'post_max_size = ' . ini_get('post_max_size') . PHP_EOL;
echo 'post_max_size+1 = ' . (ini_get('post_max_size')+1) . PHP_EOL;
echo 'post_max_size in bytes = ' . return_bytes(ini_get('post_max_size'));
function return_bytes($val) {
$val = trim($val);
$last = strtolower($val[strlen($val)-1]);
switch($last) {
// The 'G' modifier is available since PHP 5.1.0
case 'g':
$val *= 1024;
case 'm':
$val *= 1024;
case 'k':
$val *= 1024;
}
return $val;
}
?>
See also and PHP Options/Info Functions
ext/tidy
[Since 0.8.4] - [ -P Extensions/Exttidy ] - [ Online docs ]
Extension Tidy.
Tidy is a binding for the Tidy HTML clean and repair utility which allows you to not only clean and otherwise manipulate HTML documents, but also traverse the document tree.
<?php
`ob_start() <https://www.php.net/ob_start>`_;
?>
a html document
<?php
$html = `ob_get_clean() <https://www.php.net/ob_get_clean>`_;
// Specify configuration
$config = array(
'indent' => true,
'output-xhtml' => true,
'wrap' => 200);
// Tidy
$tidy = new tidy;
$tidy->parseString($html, $config, 'utf8');
$tidy->cleanRepair();
// Output
echo $tidy;
?>
See also Tidy and HTML-tidy
ext/tokenizer
[Since 0.8.4] - [ -P Extensions/Exttokenizer ] - [ Online docs ]
Extension Tokenizer.
The Tokenizer functions provide an interface to the PHP tokenizer embedded in the Zend Engine.
<?php
/*
* T_ML_COMMENT does not exist in PHP 5.
* The following three lines define it in order to
* preserve backwards compatibility.
*
* The next two lines define the PHP 5 only T_DOC_COMMENT,
* which we will mask as T_ML_COMMENT for PHP 4.
*/
if (!defined('T_ML_COMMENT')) {
define('T_ML_COMMENT', T_COMMENT);
} else {
define('T_DOC_COMMENT', T_ML_COMMENT);
}
$source = file_get_contents('example.php');
$tokens = token_get_all($source);
foreach ($tokens as $token) {
if (is_string($token)) {
// simple 1-character token
echo $token;
} else {
// token array
list($id, $text) = $token;
switch ($id) {
case T_COMMENT:
case T_ML_COMMENT: // we\'ve defined this
case T_DOC_COMMENT: // and this
// no action on comments
break;
default:
// anything else -> output 'as is'
echo $text;
break;
}
}
}
?>
See also and tokenizer
ext/wddx
[Since 0.8.4] - [ -P Extensions/Extwddx ] - [ Online docs ]
Extension WDDX.
The Web Distributed Data Exchange, or WDDX, is a free, open XML-based technology that allows Web applications created with any platform to easily exchange data with one another over the Web.
<?php
echo wddx_serialize_value("PHP to WDDX packet example", "PHP packet");
?>
See also Wddx on PHP and WDDX
ext/xdebug
[Since 0.8.4] - [ -P Extensions/Extxdebug ] - [ Online docs ]
Xdebug extension.
The Xdebug is a extension PHP which provides debugging and profiling capabilities.
<?php
class Strings
{
static function fix_string($a)
{
echo
xdebug_call_class().
"::".
xdebug_call_function().
" is called at ".
xdebug_call_`file() <https://www.php.net/file>`_.
":".
xdebug_call_line();
}
}
$ret = Strings::fix_string( 'Derick' );
?>
See also and Xdebug
ext/xmlreader
[Since 0.8.4] - [ -P Extensions/Extxmlreader ] - [ Online docs ]
Extension XMLReader.
The XMLReader extension is an XML Pull parser. The reader acts as a cursor going forward on the document stream and stopping at each node on the way.
<?php
$xmlreader = new XMLReader();
$xmlreader->xml("<xml><div>Content</div></xml>");
$xmlreader->read();
$xmlreader->read();
$xmlreader->readString();
?>
See also and xmlreader
ext/xmlrpc
[Since 0.8.4] - [ -P Extensions/Extxmlrpc ] - [ Online docs ]
Extension ext/xmlrpc.
This extension can be used to write XML-RPC servers and clients.
<?php
$request = xmlrpc_encode_request('method', array(1, 2, 3));
$context = stream_context_create(array('http' => array(
'method' => 'POST',
'header' => 'Content-Type: text/xml',
'content' => $request
)));
$file = file_get_contents('http://www.example.com/xmlrpc', false, $context);
$response = xmlrpc_decode($file);
if ($response && xmlrpc_is_fault($response)) {
trigger_error('xmlrpc: '.$response['faultString'].' ('.$response['faultCode']));
} else {
print_r($response);
}
?>
See also and XML-RPC
ext/xmlwriter
[Since 0.8.4] - [ -P Extensions/Extxmlwriter ] - [ Online docs ]
Extension ext/xmlwriter.
The XMLWriter extension wraps the libxml xmlWriter API inside PHP.
<?php
$xw = xmlwriter_open_memory();
xmlwriter_set_indent($xw, TRUE);
xmlwriter_start_document($xw, NULL, 'UTF-8');
xmlwriter_start_element($xw, 'root');
xmlwriter_write_attribute_ns($xw, 'prefix', '', 'http://www.php.net/uri');
xmlwriter_start_element($xw, 'elem1');
xmlwriter_write_attribute($xw, 'attr1', 'first');
xmlwriter_end_element($xw);
xmlwriter_full_end_element($xw);
xmlwriter_end_document($xw);
$output = xmlwriter_flush($xw, true);
print $output;
// write attribute_ns without start_element first
$xw = xmlwriter_open_memory();
var_dump(xmlwriter_write_attribute_ns($xw, 'prefix', 'id', 'http://www.php.net/uri', 'elem1'));
print xmlwriter_output_memory($xw);
?>
See also and XMLWriter and Module xmlwriter from libxml2
ext/xsl
[Since 0.8.4] - [ -P Extensions/Extxsl ] - [ Online docs ]
Extension XSL.
The XSL extension implements the XSL standard, performing XSLT transformations using the libxslt library.
<?php
// Example from the PHP manual
$xmldoc = new DOMDocument();
$xsldoc = new DOMDocument();
$xsl = new XSLTProcessor();
$xmldoc->loadXML('fruits.xml');
$xsldoc->loadXML('fruits.xsl');
libxml_use_internal_errors(true);
$result = $xsl->importStyleSheet($xsldoc);
if (!$result) {
foreach (libxml_get_errors() as $error) {
echo "Libxml error: {$error->message}\n";
}
}
libxml_use_internal_errors(false);
if ($result) {
echo $xsl->transformToXML($xmldoc);
}
?>
See also and XSL extension
ext/yaml
[Since 0.8.4] - [ -P Extensions/Extyaml ] - [ Online docs ]
Extension YAML.
This extension implements the YAML Ain't Markup Language (YAML) data serialization standard. Parsing and emitting are handled by the LibYAML library.
<?php
$addr = array(
'given' => 'Chris',
'family'=> 'Dumars',
'address'=> array(
'lines'=> '458 Walkman Dr.
Suite #292',
'city'=> 'Royal Oak',
'state'=> 'MI',
'postal'=> 48046,
),
);
$invoice = array (
'invoice'=> 34843,
'date'=> '2001-01-23',
'bill-to'=> $addr,
'ship-to'=> $addr,
'product'=> array(
array(
'sku'=> 'BL394D',
'quantity'=> 4,
'description'=> 'Basketball',
'price'=> 450,
),
array(
'sku'=> 'BL4438H',
'quantity'=> 1,
'description'=> 'Super Hoop',
'price'=> 2392,
),
),
'tax'=> 251.42,
'total'=> 4443.52,
'comments'=> 'Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.',
);
// generate a YAML representation of the invoice
$yaml = yaml_emit($invoice);
var_dump($yaml);
// convert the YAML back into a PHP variable
$parsed = yaml_parse($yaml);
// check that roundtrip conversion produced an equivalent structure
var_dump($parsed == $invoice);
?>
See also and YAML
ext/zip
[Since 0.8.4] - [ -P Extensions/Extzip ] - [ Online docs ]
Extension ext/zip.
This extension enables you to transparently read or write ZIP compressed archives and the files inside them.
<?php
$zip = new ZipArchive();
$filename = './test112.zip';
if ($zip->open($filename, ZipArchive::CREATE)!==TRUE) {
exit('cannot open <$filename>');
}
$zip->addFromString('testfilephp.txt' . time(), '#1 This is a test string added as testfilephp.txt.'.PHP_EOL);
$zip->addFromString('testfilephp2.txt' . time(), '#2 This is a test string added as testfilephp2.txt.'.PHP_EOL);
$zip->addFile($thisdir . '/too.php','/testfromfile.php');
echo 'numfiles: ' . $zip->numFiles . PHP_EOL;
echo 'status:' . $zip->status . PHP_EOL;
$zip->close();
?>
See also and Zip
ext/zlib
[Since 0.8.4] - [ -P Extensions/Extzlib ] - [ Online docs ]
Extension ext/zlib.
<?php
$filename = tempnam('/tmp', 'zlibtest') . '.gz';
echo "<html>\n<head></head>\n<body>\n<pre>\n";
$s = "Only a test, test, test, test, test, test, test, test!\n";
// open file for writing with maximum compression
$zp = gzopen($filename, 'w9');
// write string to file
gzwrite($zp, $s);
// close file
gzclose($zp);
?>
See also and Zlib
Closures Glossary
[Since 0.8.4] - [ -P Functions/Closures ] - [ Online docs ]
List of all the closures in the code.
<?php
// A closure is also a unnamed function
$closure = function ($arg) { return 'A'.strtolower($arg); }
?>
See also and The Closure Class
Empty Function
[Since 0.8.4] - [ -P Functions/EmptyFunction ] - [ Online docs ]
Function or method whose body is empty.
Such functions or methods are rarely useful. As a bare minimum, the function should return some useful value, even if constant.
A method is considered empty when it contains nothing, or contains expressions without impact.
<?php
// classic empty function
function emptyFunction() {}
class bar {
// classic empty method
function emptyMethod() {}
// classic empty function
function emptyMethodWithParent() {}
}
class barbar extends bar {
// NOT an empty method : it overwrites the parent method
function emptyMethodWithParent() {}
}
?>
Methods which overwrite another methods are omitted. Methods which are the concrete version of an abstract method are considered.
Functions Glossary
[Since 0.8.4] - [ -P Functions/Functionnames ] - [ Online docs ]
List of all the defined functions in the code.
<?php
// A function
function aFunction() {}
// Closures (not reported)
$closure = function ($arg) { }
// Methods
class foo {
function aMethod() {}
}
?>
Recursive Functions
[Since 0.8.4] - [ -P Functions/Recursive ] - [ Online docs ]
Recursive methods are methods that calls itself.
Usually, the method call itself directly. In rarer occasions, the method calls another method which calls back; such cycle might be longer.
<?php
// a recursive function ; it calls itself
function factorial($n) {
if ($n == 1) { return 1; }
return factorial($n - 1) * $n;
}
?>
Functions, methods, arrow functions and closures are identified as recursive. Higher level of recursion are not detected (function a() calls function b(), calls function a(), etc.).
Redeclared PHP Functions
[Since 0.8.4] - [ -P Functions/RedeclaredPhpFunction ] - [ Online docs ]
Function that bear the same name as a PHP function, and that are declared.
This is useful when managing backward compatibility, like emulating an old function, or preparing for newer PHP versions, like emulating new upcoming function.
<?php
if (version_compare(PHP_VERSION, 7.0) > 0) {
function split($separator, $string) {
return explode($separator, $string);
}
}
print_r( split(' ', '2 3'));
?>
Typehints
[Since 0.8.4] - [ -P Functions/Typehints ] - [ Online docs ]
List of all the types (classes or scalar) used in Typehinting.
<?php
// here, array, myObject and string are all typehints.
function foo(array $array, myObject $x, string $string) {
}
?>
See also and Type declarations
Methods Without Return
[Since 0.8.4] - [ -P Functions/WithoutReturn ] - [ Online docs ]
List of all the functions, closures, methods that have no explicit return.
Functions with the void or never returntypes, are omitted.
<?php
// With return null : Explicitly not returning
function withExplicitReturn($a = 1) {
$a++;
return null;
}
// Without indication
function withoutExplicitReturn($a = 1) {
$a++;
}
// With return type void : Explicitly not returning
function withExplicitReturnType($a = 1) : void {
$a++;
}
?>
See also and return
Empty Interfaces
[Since 0.8.4] - [ -P Interfaces/EmptyInterface ] - [ Online docs ]
Empty interfaces are a code smell. Interfaces should contains at least a method or a constant, and not be totally empty.
<?php
// an empty interface
interface empty {}
// an normal interface
interface normal {
public function i() ;
}
// a constants interface
interface constantsOnly {
const FOO = 1;
}
?>
See also Empty interfaces are bad practice and Blog : Are empty interfaces code smell?
Interfaces Names
[Since 0.8.4] - [ -P Interfaces/Interfacenames ] - [ Online docs ]
List of all the defined interfaces in the code.
<?php
// interfaceName is reported
interface interfaceName {
function interfaceMethod() ;
}
?>
Aliases
[Since 0.8.4] - [ -P Namespaces/Alias ] - [ Online docs ]
List of all aliases used, to alias namespaces.
<?php
// This is an alias
use stdClass as aClass;
// This is not an alias : it is not explicit
use stdClass;
trait t {
// This is not an alias, it's a trait usage
use otherTrait;
}
?>
See also Using namespaces: Aliasing/Importing and A Complete Guide to PHP Namespaces
Namespaces Glossary
[Since 0.8.4] - [ -P Namespaces/Namespacesnames ] - [ Online docs ]
List of all the defined namespaces in the code, using the namespace keyword.
<?php
// One reported namespace
namespace one\name\space {}
// This global namespace is reported, as it is explicit
namespace { }
?>
Global namespaces are mentioned when they are explicitly used.
Autoloading
[Since 0.8.4] - [ -P Php/AutoloadUsage ] - [ Online docs ]
Usage of the autoloading feature of PHP.
<?php
spl_autoload_register('my_autoloader');
// Old way to autoload. Deprecated in PHP 7.2
function __autoload($class ) {}
?>
Defining the __autoload() function is obsolete since PHP 7.2.
See also and __autoload
Goto Names
[Since 0.8.4] - [ -P Php/Gotonames ] - [ Online docs ]
List of all goto labels used in the code.
<?php
GOTO_NAME_1:
// reports the usage of GOTO_NAME_1
goto GOTO_NAME_1;
UNUSED_GOTO_NAME_1:
?>
See also and goto
__halt_compiler
[Since 0.8.4] - [ -P Php/Haltcompiler ] - [ Online docs ]
__halt_compiler() usage.
<?php
// open this file
$fp = fopen(__FILE__, 'r');
// seek file pointer to data
fseek($fp, __COMPILER_HALT_OFFSET__);
// and output it
var_dump(stream_get_contents($fp));
// the end of the script execution
__halt_compiler(); the installation data (eg. tar, gz, PHP, etc.)
?>
See also and __halt_compiler
Incompilable Files
[Since 0.8.4] - [ -P Php/Incompilable ] - [ Online docs ]
Files that cannot be compiled, and, as such, be run by PHP. Scripts are linted against various versions of PHP.
This is usually undesirable, as all code must compile before being executed. It may be that such files are not compilable because they are not yet ready for an upcoming PHP version.
<?php
// Can't compile this : Print only accepts one argument
print $a, $b, $c;
?>
Code that is not compilable with older PHP versions means that the code is breaking backward compatibility : good or bad is project decision.
When the code is used as a template for PHP code generation, for example at installation time, it is recommended to use a distinct file extension, so as to distinguish them from actual PHP code.
Labels
[Since 0.8.4] - [ -P Php/Labelnames ] - [ Online docs ]
List of all labels used in the code.
<?php
// A is label.
goto A:
A:
// A label may be used by several gotos.
goto A:
?>
Throw
[Since 0.8.4] - [ -P Php/ThrowUsage ] - [ Online docs ]
List of thrown exceptions.
<?php
if ($divisor === 0) {
// Throw native exception
throw new DivisionByZeroError("Shouldn't divide by one");
}
if ($divisor === 1) {
// Throw custom exception
throw new DontDivideByOneException("Shouldn't divide by one");
}
?>
See also and Exceptions
Trigger Errors
[Since 0.8.4] - [ -P Php/TriggerErrorUsage ] - [ Online docs ]
List of situations where user errors are triggered.
PHP errors are triggered with trigger_error().
<?php
if ($divisor == 0) {
trigger_error('Cannot divide by zero', E_USER_ERROR);
}
?>
See also and trigger_error
Caught Expressions
[Since 0.8.4] - [ -P Php/TryCatchUsage ] - [ Online docs ]
List of caught exceptions.
<?php
// This analyzer reports MyException and Exception
try {
doSomething();
} catch (MyException $e) {
fixIt();
} catch (\Exception $e) {
fixIt();
}
?>
See also and Exceptions
error_reporting() With Integers
[Since 0.8.4] - [ -P Structures/ErrorReportingWithInteger ] - [ Online docs ]
Using named constants with error_reporting is strongly encouraged to ensure compatibility for future versions. As error levels are added, the range of integers increases, so older integer-based error levels will not always behave as expected. (Adapted from the documentation).
<?php
// This is ready for PHP next version
error_reporting(E_ALL & ~E_DEPRECATED & ~E_STRICT & ~E_NOTICE & ~E_WARNING);
// This is not ready for PHP next version
error_reporting(2047);
// -1 and 0 are omitted, as they will be valid even is constants changes.
error_reporting(-1);
error_reporting(0);
?>
See also directive error_reporting and
error_reporting.
Eval() Usage
[Since 0.8.4] - [ -P Structures/EvalUsage ] - [ Online docs ]
Using eval() is evil.
Using eval() is bad for performances (compilation time), for caches (it won't be compiled), and for security (if it includes external data).
<?php
// Avoid using incoming data to build the `eval() <https://www.php.net/eval>`_ expression : any filtering error leads to PHP injection
$mathExpression = $_GET['mathExpression'];
$mathExpression = preg_replace('#[^0-9+\-*/\(/)]#is', '', $mathExpression); // expecting 1+2
$literalCode = '$a = '.$mathExpression.';';
eval($literalCode);
echo $a;
// If the code code given to `eval() <https://www.php.net/eval>`_ is known at compile time, it is best to put it inline
$literalCode = '`phpinfo() <https://www.php.net/phpinfo>`_;';
eval($literalCode);
?>
Most of the time, it is possible to replace the code by some standard PHP, like variable variable for accessing a variable for which you have the name.
At worse, including a pregenerated file is faster and cacheable.
There are several situations where eval() is actually the only solution :
For PHP 7.0 and later, it is important to put eval() in a try..catch expression.
See also eval and The Land Where PHP Uses `eval()
Exit() Usage
[Since 0.8.4] - [ -P Structures/ExitUsage ] - [ Online docs ]
Using exit or die() in the code makes the code untestable (it will break unit tests). Moreover, if there is no reason or string to display, it may take a long time to spot where the application is stuck.
<?php
// Throw an exception, that may be caught somewhere
throw new \Exception('error');
// Dying with error message.
die('error');
function foo() {
//exiting the function but not dying
if (somethingWrong()) {
return true;
}
}
?>
Try exiting the function/class with return, or throw exception that may be caught later in the code.
Forgotten Whitespace
[Since 0.8.4] - [ -P Structures/ForgottenWhiteSpace ] - [ Online docs ]
Forgotten whitespaces only bring misery to the code.
White spaces have been left at either end of a file : before the PHP opening tag, or after the closing tag.
Usually, such whitespaces are forgotten, and may end up summoning the infamous 'headers already sent' error. It is better to remove them.
<?php
// This script has no forgotten whitespace, not at the beginning
function foo() {}
// This script has no forgotten whitespace, not at the end
?>
See also How to fix Headers already sent error in PHP.
Iffectations
[Since 0.8.4] - [ -P Structures/Iffectation ] - [ Online docs ]
Affectations that appears in a condition.
Iffectations are a way to do both a test and an affectations.
They may also be typos, such as if ($x = 3) { ... }, leading to a constant condition.
<?php
// an iffectation : assignation in a If condition
if($connexion = mysql_connect($host, $user, $pass)) {
$res = mysql_query($connexion, $query);
}
// Iffectation may happen in while too.
while($row = mysql_fetch($res)) {
$store[] = $row;
}
?>
Multiply By One
[Since 0.8.4] - [ -P Structures/MultiplyByOne ] - [ Online docs ]
Multiplying by 1 is a fancy type cast.
If it is used to type cast a value to number, then casting (int) or (float) is clearer. This behavior may change with PHP 7.1, which has unified the behavior of all hidden casts.
<?php
// Still the same value than $m, but now cast to integer or float
$m = $m * 1;
// Still the same value than $m, but now cast to integer or float
$n *= 1;
// make typecasting clear, and merge it with the producing call.
$n = (int) $n;
?>
See also Type Juggling
@ Operator
[Since 0.8.4] - [ -P Structures/Noscream ] - [ Online docs ]
@ is the 'no scream' operator : it suppresses error output.
<?php
// Set x with incoming value, or else null.
$x = @$_GET['x'];
?>
This operator is very slow : it processes the error, and finally decides not to display it. It is often faster to check the conditions first, then run the method without @ .
You may also set display_error to 0 in the php.ini : this avoids user's error display, and keeps the error in the PHP logs, for later processing.
The only situation where @ is useful is when a native PHP function displays errors messages and there is no way to check it from the code beforehand.
This was the case with fopen(), stream_socket_server(), token_get_all(). As of PHP 7.0, they are all hiding errors when @ is active.
See also I scream, you scream, we all scream for @, Error Control Operators and Five reasons why the shut-op operator should be avoided
Not Not
[Since 0.8.4] - [ -P Structures/NotNot ] - [ Online docs ]
Double not makes a boolean, not a true .
This is a wrong casting to boolean. PHP supports (boolean) to do the same, faster and cleaner.
<?php
// Explicit code
$b = (boolean) $x;
$b = (bool) $x;
// Wrong type casting
$b = !!$x;
?>
See also Logical Operators and Type Juggling
include_once() Usage
[Since 0.8.4] - [ -P Structures/OnceUsage ] - [ Online docs ]
Usage of include_once() and require_once(). Those functions should be avoided for performances reasons.
<?php
// Including a library.
include 'lib/helpers.inc';
// Including a library, and avoiding double inclusion
include_once 'lib/helpers.inc';
?>
Try using autoload for loading classes, or use include() or require() and make it possible to include several times the same file without errors.
Using Short Tags
[Since 0.8.4] - [ -P Structures/ShortTags ] - [ Online docs ]
The code makes use of short tags. Short tags are the following : . A full scripts looks like that : .
It is recommended to avoid using short tags, and use standard PHP tags. This makes PHP code compatible with XML standards. Short tags used to be popular, but have lost it.
See also and PHP Tags
Strpos()-like Comparison
[Since 0.8.4] - [ -P Structures/StrposCompare ] - [ Online docs ]
The result of that function may be mistaken with an error.
strpos(), along with several PHP native functions, returns a string position, starting at 0, or false, in case of failure.
<?php
// This is the best comparison
if (strpos($string, 'a') === false) { }
// This is OK, as 2 won't be mistaken with false
if (strpos($string, 'a') == 2) { }
// strpos is one of the 26 functions that may behave this way
if (preg_match($regex, $string)) { }
// This works like above, catching the value for later reuse
if ($a = strpos($string, 'a')) { }
// This misses the case where 'a' is the first char of the string
if (strpos($string, 'a')) { }
// This misses the case where 'a' is the first char of the string, just like above
if (strpos($string, 'a') == 0) { }
?>
It is recommended to check the result of strpos() with === or !==, so as to avoid confusing 0 and false.
This analyzer list all the strpos()-like functions that are directly compared with == or !=. preg_match(), when its first argument is a literal, is omitted : this function only returns NULL in case of regex error.
The full list is the following :
- array_search()
- collator_compare()
- collator_get_sort_key()
- current()
- fgetc()
- file_get_contents()
- file_put_contents()
- fread()
- iconv_strpos()
- iconv_strrpos()
- imagecolorallocate()
- imagecolorallocatealpha()
- mb_strlen()
- next()
- pcntl_getpriority()
- preg_match()
- prev()
- readdir()
- stripos()
- strpos()
- strripos()
- strrpos()
- strtok()
- curl_exec()
In PHP 8.0, str_contains() will do the expected job of strpos(), with less confusion.
See also and strpos not working correctly
Throws An Assignement
[Since 0.8.4] - [ -P Structures/ThrowsAndAssign ] - [ Online docs ]
It is possible to throw an exception, and, in the same time, assign this exception to a variable.
However, the variable will never be used, as the exception is thrown, and any following code is not executed, unless the exception is caught in the same scope.
<?php
// $e is useful, though not by much
$e = new() Exception();
throw $e;
// $e is useless
throw $e = new Exception();
?>
var_dump()... Usage
[Since 0.8.4] - [ -P Structures/VardumpUsage ] - [ Online docs ]
var_dump(), print_r() or var_export() should not be left in any production code. They are debugging functions.
<?php
if ($error) {
// Debugging usage of var_dump
// And major security problem
var_dump($query);
// This is OK : the $query is logged, and not displayed
$this->log(print_r($query, true));
}
?>
They may be tolerated during development time, but must be removed so as not to have any chance to be run in production.
__toString() Throws Exception
[Since 0.8.4] - [ -P Structures/toStringThrowsException ] - [ Online docs ]
Magical method __toString() can't throw exceptions.
In fact, __toString() may not let an exception pass. If it throw an exception, but must catch it. If an underlying method throws an exception, it must be caught.
<?php
class myString {
private $string = null;
public function __construct($string) {
$this->string = $string;
}
public function __toString() {
// Do not throw exceptions in __toString
if (!is_string($this->string)) {
throw new Exception("$this->string is not a string!!");
}
return $this->string;
}
}
?>
A fatal error is displayed, when an exception is not intercepted in the __toString() function.
See also and __toString()
Binary Glossary
[Since 0.8.4] - [ -P Type/Binary ] - [ Online docs ]
List of all the integer values using the binary format.
<?php
$a = 0b10;
$b = 0B0101;
?>
See also Integer syntax and Mastering binary and bitwise in PHP
Email Addresses
[Since 0.8.4] - [ -P Type/Email ] - [ Online docs ]
List of all the email addresses that were found in the code.
Emails are detected with regex : [_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})
<?php
$email = 'contact@exakat.io';
?>
Heredoc Delimiter Glossary
[Since 0.8.4] - [ -P Type/Heredoc ] - [ Online docs ]
List of all the delimiters used to build a Heredoc string.
In the example below, EOD is the delimiter.
<?php
$a = <<<EOD
heredoc
EOD;
?>
See also and Heredoc
Hexadecimal Glossary
[Since 0.8.4] - [ -P Type/Hexadecimal ] - [ Online docs ]
List of all the integer values, written in the hexadecimal format.
<?php
$hexadecimal = 0x10;
$anotherHexadecimal =0XAF;
?>
See also and Integer Syntax
Md5 Strings
[Since 0.8.4] - [ -P Type/Md5String ] - [ Online docs ]
List of all the MD5 values hard coded in the application.
MD5 values are detected as hexadecimal strings, of length 32. No attempt at recognizing the origin value is made, so any such strings, including dummy '11111111111111111111111111111111' are reported.
<?php
// 32
$a = '0cc175b9c0f1b6a831c399e269771111';
?>
See also and MD5
Nowdoc Delimiter Glossary
[Since 0.8.4] - [ -P Type/Nowdoc ] - [ Online docs ]
List of all the delimiters used to build a Nowdoc string.
<?php
$nowdoc = <<<'EOD'
EOD;
?>
See also Nowdoc and Heredoc
Octal Glossary
[Since 0.8.4] - [ -P Type/Octal ] - [ Online docs ]
List of all the integer values using the octal format : an integer starting with an initial 0.
<?php
$a = 1234; // decimal number
$a = 0123; // octal number (equivalent to 83 decimal)
// silently valid for PHP 5.x
$a = 01283; // octal number (equivalent to 10 decimal)
?>
Putting an initial 0 is often innocuous, but in PHP, 0755 and 755 are not the same. The second is actually 1363 in octal, and will not provide the expected privileges.
See also and Integers
URL List
[Since 0.8.4] - [ -P Type/Url ] - [ Online docs ]
List of all the URL addresses that were found in the code.
<?php
// the first argument is recognized as an URL
ftp_connect('http://www.example.com/', $port, $timeout);
// the string argument is recognized as an URL
$source = 'https://www.other-example.com/';
?>
See also and Uniform Resource Identifier
Variable References
[Since 0.8.4] - [ -P Variables/References ] - [ Online docs ]
Variables that are references.
<?php
$a = '1'; // not a reference
$b = &$a; // a reference
?>
See also and References
Static Variables
[Since 0.8.4] - [ -P Variables/StaticVariables ] - [ Online docs ]
In PHP, variables may be static. They will survive after the function execution end, and will be available at the next function run. They are distinct from globals, which are available application wide, and from static properties, which are tied to a class of objects.
<?php
function foo() {
// static variable
static $count = 0;
echo ++$count;
}
class bar {
// This is not a static variable :
// it is a static property
static $property = 1;
}
?>
See also and Using static variables
Variables With Long Names
[Since 0.8.4] - [ -P Variables/VariableLong ] - [ Online docs ]
This analysis collects all variables with more than 20 characters longs. This may be configured with the variableLength parameter.
<?php
// Quite a long variable name
$There_is nothing_wrong_with_long_variable_names_They_tend_to_be_rare_and_that_make_them_noteworthy = 1;
?>
PHP has not limitation on variable name size. While short name are often obscure, long names are usually better. Yet, there exists a limit to convenient variable name length.
See also and Basics
Non Ascii Variables
[Since 0.8.4] - [ -P Variables/VariableNonascii ] - [ Online docs ]
PHP allows certain characters in variable names. The variable name must only include letters, figures, underscores and ASCII characters from 128 to 255.
In practice, letters outside the scope of the intervalle [a-zA-Z0-9_] are rare, and require more care when editing the code or passing it from OS to OS.
Also, certain letter might appear similar to the roman ones, and be part of a different alphabet. This is the case, for example, of the cyrillic alphabet, where `А` (cyrillic A, U+0410) is actually different from `A` (Latin A, U+0041). Some dashes and spaces may be valid in PHP variable names, and look very confusing.
<?php
// person, in Simplified Chinese
class 人 {
// An actual working class in PHP.
public function __construct() {
echo __CLASS__;
}
}
// people = new person();
$人民 = new 人();
?>
See also and Variables
Used Once Variables
[Since 0.8.4] - [ -P Variables/VariableUsedOnce ] - [ Online docs ]
This is the list of used once variables.
<?php
// The variables below never appear again in the code
$writtenOnce = 1;
foo($readOnce);
?>
Such variables are useless. Variables must be used at least twice : once for writing, once for reading, at least. It is recommended to remove them.
In special situations, variables may be used once :
+ PHP predefined variables, as they are already initialized. They are omitted in this analyze.
+ Interface function's arguments, since the function has no body; They are omitted in this analyze.
+ Dynamically created variables ($$x, ${$this->y} or also using extract), as they are runtime values and can't be determined at static code time. They are reported for manual review.
+ Dynamically included files will provide in-scope extra variables.
This rule counts variables at the application level, and not at a method scope level.
See also and class
Variable Variables
[Since 0.8.4] - [ -P Variables/VariableVariables ] - [ Online docs ]
A variable variable takes the value of a variable and treats that as the name of a variable.
PHP has the ability to dynamically use a variable.
<?php
// Normal variable
$a = 'b';
$b = 'c';
// Variable variable
$d = $$b;
// Variable variable in string
$d = "$\{$b\}";
?>
They are also called 'dynamic variable'.
See also and Variable variables
Abstract Class Usage
[Since 0.8.4] - [ -P Classes/Abstractclass ] - [ Online docs ]
List of all abstract classes being used.
<?php
abstract class foo {
function foobar();
}
class bar extends foo {
// extended method
function foobar() {
// doSomething()
}
// extra method
function barbar() {
// doSomething()
}
}
?>
See also and Classes abstraction
Abstract Methods Usage
[Since 0.8.4] - [ -P Classes/Abstractmethods ] - [ Online docs ]
List of all abstract methods being used.
<?php
// abstract class
abstract class foo {
// abstract method
function foobar();
}
class bar extends foo {
// extended abstract method
function foobar() {
// doSomething()
}
// extra method
function barbar() {
// doSomething()
}
}
?>
See also and Classes abstraction
Clone Usage
[Since 0.8.4] - [ -P Classes/CloningUsage ] - [ Online docs ]
List of all clone situations.
<?php
$dateTime = new DateTime();
echo (clone $dateTime)->format('Y');
?>
See also and Object cloning
Bad Constants Names
[Since 0.8.4] - [ -P Constants/BadConstantnames ] - [ Online docs ]
PHP's manual recommends that developer do not use constants with the convention __NAME__ . Those are reserved for PHP future use.
For example, __TRAIT__ recently appeared in PHP, as a magic constant. In the future, other may appear.
<?php
const __MY_APP_CONST__ = 1;
const __MY_APP_CONST__ = 1;
define('__MY_OTHER_APP_CONST__', 2);
?>
The analyzer will report any constant which name is __.*.__ , or even _.*_ (only one underscore).
See also and Constants
Variable Constants
[Since 0.8.4] - [ -P Constants/VariableConstant ] - [ Online docs ]
Variable constants are constants whose value is accessed via the function constant(). Otherwise, there is no way to dynamically access a constant (aka, when the developer has the name of the constant as a incoming parameter, and it requires the value of it).
<?php
const A = 'constant_value';
$constant_name = 'A';
$variableConstant = constant($constant_name);
?>
See also and `constant()
Empty Traits
[Since 0.8.4] - [ -P Traits/EmptyTrait ] - [ Online docs ]
List of all empty trait defined in the code.
<?php
// empty trait
trait t { }
// Another empty trait
trait t2 {
use t;
}
?>
Such traits may be reserved for future use. They may also be forgotten, and dead code.
Redefined PHP Traits
[Since 0.8.4] - [ -P Traits/Php ] - [ Online docs ]
List of all traits that bears name of a PHP trait. Although, at the moment (PHP 8.1), there are no PHP trait defined.
Traits Usage
[Since 0.8.4] - [ -P Traits/TraitUsage ] - [ Online docs ]
Usage of traits in the code.
<?php
trait t {
function t() {
echo 'I\'m in t';
}
}
class foo {
use t;
}
$x = new foo();
$x->t();
?>
See also and Traits
Trait Names
[Since 0.8.4] - [ -P Traits/Traitnames ] - [ Online docs ]
List all the trait's names, found in the code.
<?php
// This trait is called 't'
trait t {}
?>
See also and Traits
PHP Alternative Syntax
[Since 0.8.4] - [ -P Php/AlternativeSyntax ] - [ Online docs ]
Identify the usage of alternative syntax in the code, for If then, Switch, While, For and Foreach.
<?php
// Normal syntax
if ($a == 1) {
print $a;
}
// Alternative syntax : identical to the previous one.
if ($a == 1) :
print $a;
endif;
?>
See also and Alternative syntax
Short Syntax For Arrays
[Since 0.8.4] - [ -P Arrays/ArrayNSUsage ] - [ Online docs ]
Arrays written with the new short syntax.
PHP 5.4 introduced the new short syntax, with square brackets. The previous syntax, based on the array() keyword is still available.
<?php
// All PHP versions array
$a = array(1, 2, 3);
// PHP 5.4+ arrays
$a = [1, 2, 3];
?>
See also and Array
Inclusions
[Since 0.8.4] - [ -P Structures/IncludeUsage ] - [ Online docs ]
List of all inclusions. Inclusions are made with include(), include_once(), require() and require_once().
<?php
include 'library.php';
// display is a function defined in 'library.php';
display('Message');
?>
See also Include and Require
ext/file
[Since 0.8.4] - [ -P Extensions/Extfile ] - [ Online docs ]
Filesystem functions from standard.
Extension that handle access to file on the file system.
<?php
$row = 1;
if (($handle = fopen('test.csv', 'r')) !== FALSE) {
while (($data = fgetcsv($handle, 1000, ',')) !== FALSE) {
$num = count($data);
echo '<p> $num fields in line $row: <br /></p>'.PHP_EOL;
$row++;
for ($c=0; $c < $num; $c++) {
echo $data[$c] . '<br />'.PHP_EOL;
}
}
fclose($handle);
}
?>
See also and filesystem
Use With Fully Qualified Name
[Since 0.8.4] - [ -P Namespaces/UseWithFullyQualifiedNS ] - [ Online docs ]
Use statement doesn't require a fully qualified name.
PHP manual recommends not to use fully qualified name (starting with \) when using the 'use' statement : they are "the leading backslash is unnecessary and not recommended, as import names must be fully qualified, and are not processed relative to the current namespace".
<?php
// Recommended way to write a use statement.
use A\B\C\D as E;
// No need to use the initial \
use \A\B\C\D as F;
?>
ext/array
[Since 0.8.4] - [ -P Extensions/Extarray ] - [ Online docs ]
Core functions processing arrays.
These functions manipulate arrays in various ways. Arrays are essential for storing, managing, and operating on sets of variables.
This is not a real extension : it is a documentation section, that helps classifying the functions.
<?php
function odd($var)
{
// returns whether the input integer is odd
return($var & 1);
}
function even($var)
{
// returns whether the input integer is even
return(!($var & 1));
}
$array1 = array('a'=>1, 'b'=>2, 'c'=>3, 'd'=>4, 'e'=>5);
$array2 = array(6, 7, 8, 9, 10, 11, 12);
echo 'Odd :'.PHP_EOL;
print_r(array_filter($array1, 'odd'));
echo 'Even:'.PHP_EOL;
print_r(array_filter($array2, 'even'));
?>
See also and Arrays
ext/info
[Since 0.8.4] - [ -P Extensions/Extinfo ] - [ Online docs ]
PHP Options and Information.
These functions enable you to get a lot of information about PHP itself, e.g. runtime configuration, loaded extensions, version and much more.
<?php
/*
Our php.ini contains the following settings:
display_errors = On
register_globals = Off
post_max_size = 8M
*/
echo 'display_errors = ' . ini_get('display_errors') . "\n";
echo 'register_globals = ' . ini_get('register_globals') . "\n";
echo 'post_max_size = ' . ini_get('post_max_size') . "\n";
echo 'post_max_size+1 = ' . (ini_get('post_max_size')+1) . "\n";
echo 'post_max_size in bytes = ' . return_bytes(ini_get('post_max_size'));
function return_bytes($val) {
$val = trim($val);
$last = strtolower($val[strlen($val)-1]);
switch($last) {
// The 'G' modifier is available since PHP 5.1.0
case 'g':
$val *= 1024;
case 'm':
$val *= 1024;
case 'k':
$val *= 1024;
}
return $val;
}
?>
See also and PHP Options And Information
ext/math
[Since 0.8.4] - [ -P Extensions/Extmath ] - [ Online docs ]
Core functions that provides math standard functions.
This is not a real extension : it is a documentation section, that helps sorting the functions.
<?php
echo decbin(12) . PHP_EOL;
echo decbin(26);
?>
See also and Mathematical Functions
$HTTP_RAW_POST_DATA Usage
[Since 0.8.4] - [ -P Php/RawPostDataUsage ] - [ Online docs ]
$HTTP_RAW_POST_DATA is deprecated, and should be replaced by php://input .
$HTTP_RAW_POST_DATA is deprecated since PHP 5.6.
It is possible to prepare code to this lack of feature by setting always_populate_raw_post_data to -1.
<?php
// PHP 5.5 and older
$postdata = $HTTP_RAW_POST_DATA;
// PHP 5.6 and more recent
$postdata = file_get_contents(php://input);
?>
See also $HTTP_RAW_POST_DATA variable.
Useless Instructions
[Since 0.8.4] - [ -P Structures/UselessInstruction ] - [ Online docs ]
Those instructions are useless, or contains useless parts.
For example, an addition whose result is not stored in a variable, or immediately used, does nothing : it is actually performed, and the result is lost. Just plain lost. In fact, PHP might detect it, and optimize it away.
Here the useless instructions that are spotted :
<?php
// Concatenating with an empty string is useless.
$string = 'This part '.$is.' useful but '.$not.'';
// This is a typo, that PHP turns into a constant, then a string, then nothing.
continue;
// Empty string in a concatenation
$a = 'abc' . '';
// Returning expression, whose result is not used (additions, comparisons, properties, closures, new without =, ...)
1 + 2;
// Returning post-incrementation
function foo($a) {
return $a++;
}
// `array_replace() <https://www.php.net/array_replace>`_ with only one argument
$replaced = array_replace($array);
// `array_replace() <https://www.php.net/array_replace>`_ is OK with ...
$replaced = array_replace(...$array);
// @ operator on source array, in foreach, or when assigning literals
$array = @array(1,2,3);
// Multiple comparisons in a for loop : only the last is actually used.
for($i = 0; $j = 0; $j < 10, $i < 20; ++$j, ++$i) {
print $i.' '.$j.PHP_EOL;
}
// Counting the keys and counting the array is the same.
$c = count(array_keys($array))
//array_keys already provides an array with only unique values, as they were keys in a previous array
$d = array_unique(array_keys($file['messages']))
// No need for assignation inside the ternary operator
$closeQuote = $openQuote[3] === "'" ? substr($openQuote, 4, -2) : $closeQuote = substr($openQuote, 3);
?>
Abstract Static Methods
[Since 0.8.4] - [ -P Classes/AbstractStatic ] - [ Online docs ]
Methods cannot be both abstract and static. Static methods belong to a class, and will not be overridden by the child class. For normal methods, PHP will start at the object level, then go up the hierarchy to find the method. With static, it is necessary to mention the name, or use Late Static Binding, with self or static. Hence, it is useless to have an abstract static method : it should be a static method.
A child class is able to declare a method with the same name than a static method in the parent, but those two methods will stay independent.
This is not the case anymore in PHP 7.0+.
<?php
abstract class foo {
// This is not possible
static abstract function bar() ;
}
?>
See also and Why does PHP 5.2+ disallow abstract static class methods?
Invalid Constant Name
[Since 0.8.4] - [ -P Constants/InvalidName ] - [ Online docs ]
There is a naming convention for PHP constants names.
According to PHP's manual, constant names, ' A valid constant name starts with a letter or underscore, followed by any number of letters, numbers, or underscores.'.
Constant, must follow this regex : /[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*/ .
In particular when defined using define() function, no error is produced. When using const , on the other hand, the name must be valid at linting time.
<?php
define('+3', 1); // wrong constant name!
echo constant('+3'); // invalid constant access
// This won't compile, with a syntax error.
// const 3A = 3;
?>
See also and Constants
Multiple Constant Definition
[Since 0.8.4] - [ -P Constants/MultipleConstantDefinition ] - [ Online docs ]
Some constants are defined several times in your code. This will lead to a fatal error, if they are defined during the same execution.
Multiple definitions may happens at bootstrap, when the application code is collecting information about the current environment. It may also happen at inclusion time, which one set of constant being loaded, while other definition are not, avoiding conflict. Both are false positive.
<?php
// OS is defined twice.
if (PHP_OS == 'Windows') {
define('OS', 'Win');
} else {
define('OS', 'Other');
}
?>
See also and class
Wrong Optional Parameter
[Since 0.8.4] - [ -P Functions/WrongOptionalParameter ] - [ Online docs ]
Wrong placement of optional parameters.
PHP parameters are optional when they defined with a default value, like this :
<?php
function x($arg = 1) {
// PHP code here
}
?>
When a function have both compulsory and optional parameters, the compulsory ones should appear first, and the optional should appear last :
<?php
function x($arg, $arg2 = 2) {
// PHP code here
}
?>
PHP solves this problem at runtime, assign values in the same other, but will miss some of the default values and emits warnings.
It is better to put all the optional parameters at the end of the method's signature.
Optional parameter wrongly placed are now a Notice in PHP 8.0. The only previous case that is allowed in PHP 8.0 and also in this analysis, is when the null value is used as default for typed arguments.
See also and Function arguments
Use === null
[Since 0.8.4] - [ -P Php/IsnullVsEqualNull ] - [ Online docs ]
It is faster to use === null than the function is_null().
<?php
// Operator === is faster
if ($a === null) {
}
// Function call is slow
if (is_null($a)) {
}
?>
This is a micro-optimisation. And being used frequently, and in loops, it may yield visible speed up.
See also and is_null
Assertions
[Since 0.8.4] - [ -P Php/AssertionUsage ] - [ Online docs ]
Usage of assertions, to add checks within PHP code.
Assertions should be used as a debugging feature only. You may use them for sanity-checks that test for conditions that should always be TRUE and that indicate some programming errors if not or to check for the presence of certain features like extension functions or certain system limits and features.
<?php
function foo($string) {
assert(!empty($string), 'An empty string was provided!');
echo '['.$string.']';
}
?>
See also and assert
$this Is Not An Array
[Since 0.8.4] - [ -P Classes/ThisIsNotAnArray ] - [ Online docs ]
$this variable represents the current object and it is not an array.
This is unless the class (or its parents) has the ArrayAccess interface, or extends ArrayObject or SimpleXMLElement .
<?php
// $this is an array
class Foo extends ArrayAccess {
function bar() {
++$this[3];
}
}
// $this is not an array
class Foo2 {
function bar() {
++$this[3];
}
}
?>
See also ArrayAccess, ArrayObject and The Basics
One Variable String
[Since 0.8.4] - [ -P Type/OneVariableStrings ] - [ Online docs ]
These strings only contains one variable or property or array.
<?php
$a = 0;
$b = "$a"; // This is a one-variable string
// Better way to write the above
$b = (string) $a;
// Alternatives :
$b2 = "$a[1]"; // This is a one-variable string
$b3 = "$a->b"; // This is a one-variable string
$c = "d";
$d = "D";
$b4 = "{$$c}";
$b5 = "{$a->foo()}";
?>
When the goal is to convert a variable to a string, it is recommended to use the type casting (string) operator : it is then clearer to understand the conversion. It is also marginally faster, though very little.
See also Strings and Type Juggling
Cast Usage
[Since 0.8.4] - [ -P Php/CastingUsage ] - [ Online docs ]
List of all cast usage.
PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used.
<?php
if (is_int($_GET['x'])) {
$number = (int) $_GET['x'];
} else {
error_display('a wrong value was provided for "x"');
}
?>
Until PHP 7.2, a (unset) operator was available. It had the same role as unset()
See also Type Juggling and unset
Function Subscripting
[Since 0.8.4] - [ -P Structures/FunctionSubscripting ] - [ Online docs ]
It is possible to use the result of a methodcall directly as an array, without storing the result in a temporary variable.
This works, given that the method actually returns an array.
This syntax was not possible until PHP 5.4. Until then, it was compulsory to store the result in a variable first. Although this is now superfluous, it has been a standard syntax in PHP, and is still being used.
<?php
function foo() {
return array(1 => 'a', 'b', 'c');
}
echo foo()[1]; // displays 'a';
// Function subscripting, the old way
function foo() {
return array(1 => 'a', 'b', 'c');
}
$x = foo();
echo $x[1]; // displays 'a';
?>
Storing the result in a variable is still useful if the result is actually used more than once.
See also and Accessing array elements with square bracket syntax
Nested Loops
[Since 0.8.4] - [ -P Structures/NestedLoops ] - [ Online docs ]
Nested loops happens when a loop (while, do..while, for, foreach), is used inside another loop.
<?php
// Nested loops
foreach($array as $a) {
foreach ($letters as $b) {
// This is performed count($array) * count($letters) times.
doSomething();
}
}
?>
Such structure tends to require a lot of processing, as the size of both loops have to be multiplied to estimate the actual payload. They should be avoided as much as possible. This may no be always possible, though.
Nested loops are worth a check for performances reasons, as they will process a lot of times the same instructions.
[Since 0.8.4] - [ -P Php/EchoTagUsage ] - [ Online docs ]
Usage of the short echo tab, , that echo's directly the following content.
?>
Static Methods Can't Contain $this
[Since 0.8.4] - [ -P Classes/StaticContainsThis ] - [ Online docs ]
Static methods are also called class methods : they may be called even if the class has no instantiated object. Thus, the local variable $this won't exist, PHP will set it to NULL as usual.
<?php
class foo {
// Static method may access other static methods, or property, or none.
static function staticBar() {
// This is not possible in a static method
return self::otherStaticBar() . static::$staticProperty;
}
static function bar() {
// This is not possible in a static method
return $this->property;
}
}
?>
Either this is not a static method, which is fixed by removing the static keyword, or replace all $this mention by static properties Class::$property .
See also and `Static Keyword
While(List() = Each())
[Since 0.8.4] - [ -P Structures/WhileListEach ] - [ Online docs ]
This code structure is quite old : it should be replace by the more modern and efficient foreach.
This structure is deprecated since PHP 7.2. It may disappear in the future.
<?php
while(list($key, $value) = each($array)) {
doSomethingWith($key) and $value();
}
foreach($array as $key => $value) {
doSomethingWith($key) and $value();
}
?>
See also and PHP RFC: Deprecations for PHP 7.2 : Each()
Several Instructions On The Same Line
[Since 0.8.4] - [ -P Structures/OneLineTwoInstructions ] - [ Online docs ]
Usually, instructions do not share their line : one instruction, one line.
This is good for readability, and help at understanding the code. This is especially important when fast-reading the code to find some special situation, where such double-meaning line way have an impact.
<?php
switch ($x) {
// Is it a fallthrough or not ?
case 1:
doSomething(); break;
// Easily spotted break.
case 1:
doSomethingElse();
break;
default :
doDefault();
break;
}
?>
See also and Object Calisthenics, rule # 5
Multiples Identical Case
[Since 0.8.4] - [ -P Structures/MultipleDefinedCase ] - [ Online docs ]
Some cases are defined multiple times, but only one will be processed. Check the list of cases, and remove the extra one.
Exakat finds the value of the cases as much as possible, and ignore any dynamic cases (using variables).
<?php
const A = 1;
case ($x) {
case 1 :
break;
case true: // This is a duplicate of the previous
break;
case 1 + 0: // This is a duplicate of the previous
break;
case 1.0 : // This is a duplicate of the previous
break;
case A : // The A constant is actually 1
break;
case $y : // This is not reported.
break;
default:
}
?>
It is also possible to write a valid switch statement, with all identical cases, and yet, different meaning each time. This is considered an edge case, and shall be manually removed.
<?php
$a = 10;
switch (13) {
case ++$a:
echo '1) '. $a;
break;
case ++$a:
echo '2) '. $a;
break;
case ++$a:
echo '3) '. $a;
break;
}
?>
Switch Without Default
[Since 0.8.4] - [ -P Structures/SwitchWithoutDefault ] - [ Online docs ]
Always use a default statement in switch() and match().
Switch statements hold a number of 'case' that cover all known situations, and a 'default' one which is executed when all other options are exhausted.
For Match statements, a missing default will lead to the UnhandledMatchError exception being raised. On the other hand, the switch statement will simply exit without action nor alert.
<?php
// Missing default
switch($format) {
case 'gif' :
processGif();
break 1;
case 'jpeg' :
processJpeg();
break 1;
case 'bmp' :
throw new UnsupportedFormat($format);
}
// In case $format is not known, then switch is ignored and no processing happens, leading to preparation errors
// switch with default
switch($format) {
case 'text' :
processText();
break 1;
case 'jpeg' :
processJpeg();
break 1;
case 'rtf' :
throw new UnsupportedFormat($format);
default :
throw new UnknownFileFormat($format);
}
// In case $format is not known, an exception is thrown for processing
?>
Most of the time, switch() do need a default case, so as to catch the odd situation where the 'value is not what it was expected'. This is a good place to catch unexpected values, to set a default behavior.
See also and UnhandledMatchError
$this Belongs To Classes Or Traits
[Since 0.8.4] - [ -P Classes/ThisIsForClasses ] - [ Online docs ]
The pseudo-variable $this must be used inside a class or trait, or bound closures.
$this variable represents the current object, inside a class or trait scope
It is a pseudo-variable, and should be used within class's or trait's methods and not outside. It should also not be used in static methods.
PHP 7.1 is stricter and check for $this at several situations.
<?php
// as an argument
function foo($this) {
// Using global
global $this;
// Using static (not a property)
static $this;
// Can't unset it
unset($this);
try {
// inside a foreach
foreach($a as $this) { }
foreach($a as $this => $b) { }
foreach($a as $b => $this) { }
} catch (Exception $this) {
// inside a catch
}
// with Variable Variable
$a = this;
$$a = 42;
}
class foo {
function bar() {
// Using references
$a =& $this;
$a = 42;
// Using `extract() <https://www.php.net/extract>`_, `parse_str() <https://www.php.net/parse_str>`_ or similar functions
extract([this => 42]); // throw new Error(Cannot re-assign $this)
var_dump($this);
}
static function __call($name, $args) {
// Using __call
var_dump($this); // prints object(C)#1 (0) {}, php-7.0 printed NULL
$this->test(); // prints ops
}
}
?>
See also and class
Nested Ternary
[Since 0.8.4] - [ -P Structures/NestedTernary ] - [ Online docs ]
Ternary operators should not be nested too deep.
They are a convenient instruction to apply some condition, and avoid a if() structure. It works best when it is simple, like in a one liner.
However, ternary operators tends to make the syntax very difficult to read when they are nested. It is then recommended to use an if() structure, and make the whole code readable.
<?php
// Simple ternary expression
echo ($a == 1 ? $b : $c) ;
// Nested ternary expressions
echo ($a === 1 ? $d === 2 ? $b : $d : $d === 3 ? $e : $c) ;
echo ($a === 1 ? $d === 2 ? $f ===4 ? $g : $h : $d : $d === 3 ? $e : $i === 5 ? $j : $k) ;
//Previous expressions, written as a if / Then expression
if ($a === 1) {
if ($d === 2) {
echo $b;
} else {
echo $d;
}
} else {
if ($d === 3) {
echo $e;
} else {
echo $c;
}
}
if ($a === 1) {
if ($d === 2) {
if ($f === 4) {
echo $g;
} else {
echo $h;
}
} else {
echo $d;
}
} else {
if ($d === 3) {
echo $e;
} else {
if ($i === 5) {
echo $j;
} else {
echo $k;
}
}
}
?>
This is a separate analysis from PHP's preventing nested ternaries without parenthesis.
See also Nested Ternaries are Great and Php/NestedTernaryWithoutParenthesis
Non-constant Index In Array
[Since 0.8.4] - [ -P Arrays/NonConstantArray ] - [ Online docs ]
Undefined constants revert as strings in Arrays. They are also called barewords .
In $array[index] , PHP cannot find index as a constant, but, as a default behavior, turns it into the string index .
This default behavior raise concerns when a corresponding constant is defined, either using define() or the const keyword (outside a class). The definition of the index constant will modify the behavior of the index, as it will now use the constant definition, and not the 'index' string.
<?php
// assign 1 to the element index in $array
// index will fallback to string
$array[index] = 1;
//PHP Notice: Use of undefined constant index - assumed 'index'
echo $array[index]; // display 1 and the above error
echo "$array[index]"; // display 1
echo "$array['index']"; // Syntax error
define('index', 2);
// now 1 to the element 2 in $array
$array[index] = 1;
?>
It is recommended to make index a real string (with ' or "), or to define the corresponding constant to avoid any future surprise.
Note that PHP 7.2 removes the support for this feature.
See also PHP RFC: Deprecate and Remove Bareword (Unquoted) Strings and Syntax
Undefined Constants
[Since 0.8.4] - [ -P Constants/UndefinedConstants ] - [ Online docs ]
Constants definition can't be located.
Those constants are not defined in the code, and will raise errors, or use the fallback mechanism of being treated like a string.
<?php
const A = 1;
define('B', 2);
// here, C is not defined in the code and is reported
echo A.B.C;
?>
It is recommended to define them all, or to avoid using them.
See also and Constants
Instantiating Abstract Class
[Since 0.8.4] - [ -P Classes/InstantiatingAbstractClass ] - [ Online docs ]
PHP cannot instantiate an abstract class.
The classes are actually abstract classes, and should be derived into a concrete class to be instantiated.
<?php
abstract class Foo {
protected $a;
}
class Bar extends Foo {
protected $b;
}
// instantiating a concrete class.
new Bar();
// instantiating an abstract class.
// In real life, this is not possible also because the definition and the instantiation are in the same file
new Foo();
?>
See also and Class Abstraction
Class, Interface, Enum Or Trait With Identical Names
[Since 0.8.4] - [ -P Classes/CitSameName ] - [ Online docs ]
The following names are used at the same time for classes, interfaces or traits. For example,
<?php
class a { /* some definitions */ }
interface a { /* some definitions */ }
trait a { /* some definitions */ }
enum a { /* some definitions */ } // PHP 8.1
?>
Even if they are in different namespaces, identical names makes classes easy to confuse. This is often solved by using alias at import time : this leads to more confusion, as a class suddenly changes its name.
Internally, PHP use the same list for all classes, interfaces and traits. As such, it is not allowed to have both a trait and a class with the same name.
In PHP 4, and PHP 5 before namespaces, it was not possible to have classes with the same name. They were simply included after a check.
Empty Try Catch
[Since 0.8.4] - [ -P Structures/EmptyTryCatch ] - [ Online docs ]
The code does try, then catch errors but do no act upon the error.
<?php
try {
doSomething();
} catch (Throwable $e) {
// ignore this
}
?>
At worst, the error should be logged, so as to measure the actual usage of the catch expression.
catch( Exception $e) (PHP 5) or catch(Throwable $e) with empty catch block should be banned. They ignore any error and proceed as if nothing happened. At worst, the event should be logged for future analysis.
See also Empty Catch Clause.
ext/pcntl
[Since 0.8.4] - [ -P Extensions/Extpcntl ] - [ Online docs ]
Extension for process control.
Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a web server environment and unexpected results may happen if any Process Control functions are used within a web server environment.
<?php
declare(ticks=1);
$pid = pcntl_fork();
if ($pid == -1) {
die('could not fork');
} else if ($pid) {
exit(); // we are the parent
} else {
// we are the child
}
// detatch from the controlling terminal
if (posix_setsid() == -1) {
die('could not detach from terminal');
}
// setup signal handlers
pcntl_signal(SIGTERM, 'sig_handler');
pcntl_signal(SIGHUP, 'sig_handler');
// loop forever performing tasks
while (1) {
// do something interesting here
}
function sig_handler($signo)
{
switch ($signo) {
case SIGTERM:
// handle shutdown tasks
exit;
break;
case SIGHUP:
// handle restart tasks
break;
default:
// handle all other signals
}
}
?>
See also and Process Control
Undefined Classes
[Since 0.8.4] - [ -P Classes/UndefinedClasses ] - [ Online docs ]
Those classes are used in the code, but there are no definition for them.
This may happens under normal conditions, if the application makes use of an unsupported extension, that defines extra classes;
or if some external libraries, such as PEAR, are not provided during the analysis.
<?php
// FPDF is a classic PDF class, that is usually omitted by Exakat.
$o = new FPDF();
// Exakat reports undefined classes in instanceof
// PHP ignores them
if ($o instanceof SomeClass) {
// doSomething();
}
// Classes may be used in typehint too
function foo(TypeHintClass $x) {
// doSomething();
}
?>
This analysis also checks in attributes.
ext/redis
[Since 0.8.4] - [ -P Extensions/Extredis ] - [ Online docs ]
Extension ext/redis.
The phpredis extension provides an API for communicating with the Redis key-value store.
<?php
$redis = new Redis();
$redis->connect('127.0.0.1', 6379);
$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_NONE); // don't serialize data
$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_PHP); // use built-in serialize/unserialize
$redis->setOption(Redis::OPT_SERIALIZER, Redis::SERIALIZER_IGBINARY); // use igBinary serialize/unserialize
$redis->setOption(Redis::OPT_PREFIX, 'myAppName:'); // use custom prefix on all keys
/* Options for the SCAN family of commands, indicating whether to abstract
empty results from the user. If set to SCAN_NORETRY (the default), phpredis
will just issue one SCAN command at a time, sometimes returning an empty
array of results. If set to SCAN_RETRY, phpredis will retry the scan command
until keys come back OR Redis returns an iterator of zero
*/
$redis->setOption(Redis::OPT_SCAN, Redis::SCAN_NORETRY);
$redis->setOption(Redis::OPT_SCAN, Redis::SCAN_RETRY);
?>
See also A PHP extension for Redis and Redis
Htmlentities Calls
[Since 0.8.4] - [ -P Structures/Htmlentitiescall ] - [ Online docs ]
htmlentities() and htmlspecialchars() are used to prevent injecting special characters in HTML code. As a bare minimum, they take a string and encode it for HTML.
The second argument of the functions is the type of protection. The protection may apply to quotes or not, to HTML 4 or 5, etc. It is highly recommended to set it explicitly.
The third argument of the functions is the encoding of the string. In PHP 5.3, it is ISO-8859-1 , in 5.4, was UTF-8 , and in 5.6, it is now default_charset, a php.ini configuration that has the default value of UTF-8 . It is highly recommended to set this argument too, to avoid distortions from the configuration.
<?php
$str = 'A quote is <b>bold</b>';
// Outputs, without depending on the php.ini: A 'quote' is <b>bold</b>
echo htmlentities($str, ENT_QUOTES, 'UTF-8');
// Outputs, while depending on the php.ini: A quote is <b>bold</b>
echo htmlentities($str);
?>
Also, note that arguments 2 and 3 are constants and string, respectively, and should be issued from the list of values available in the manual. Other values than those will make PHP use the default values.
See also htmlentities and htmlspecialchars
Undefined Class Constants
[Since 0.8.4] - [ -P Classes/UndefinedConstants ] - [ Online docs ]
Class constants that are used, but never defined. This yield a fatal error upon execution, but no feedback at compile level.
This analysis takes into account native PHP class constants, extensions and stubs. It also disambiguate enumeration cases.
<?php
class foo {
const A = 1;
}
function foo(Foo $f) {
// here, C is not defined in the code and is reported
echo foo::A.foo::B.foo::C;
// This is also an undefined constant
echo $f::B;
}
?>
Constants are searched in the typed class or interface, and their parent. They are not searched in the children, since the children are not necessarily available, unless the class is abstract. In particular, one of the children may not define the constant, and when such child is used, it will satisfy the type, but not the constant definition.
See also and Class constants
Used Once Variables (In Scope)
[Since 0.8.4] - [ -P Variables/VariableUsedOnceByContext ] - [ Online docs ]
This is the list of used once variables, scope by scope. Those variables are used once in a function, a method, a class or a namespace. In any case, this means the variable is read or written, while it should be used at least twice.
Static and global variables are omitted here : they may be used multiple times by having the method being called multiple times.
Blind variables, which are defined in a foreach() structure, are also omitted : the loop will use them multiple time, assigning different values each time.
Parameters that are inherited from parent classes' methods are also omitted : they are imposed by the structure, and cannot be avoided.
<?php
function foo() {
// The variables below never appear twice, inside foo()
$writtenOnce = 1;
foo($readOnce);
// They do appear again in other functions, or in global space.
}
function bar() {
$writtenOnce = 1;
foo($readOnce);
}
?>
Undefined Functions
[Since 0.8.4] - [ -P Functions/UndefinedFunctions ] - [ Online docs ]
Some functions are called, but not defined in the code. This means that the functions are probably defined in a missing library, or in an extension. If not, this will yield a Fatal error at execution.
<?php
// Undefined function
foo($a);
// valid function, as it belongs to the ext/yaml extension
$parsed = yaml_parse($yaml);
// This function is not defined in the a\b\c namespace, nor in the global namespace
a\b\c\foo();
?>
See also and Functions
Deprecated PHP Functions
[Since 0.8.4] - [ -P Php/Deprecated ] - [ Online docs ]
The following functions are deprecated. It is recommended to stop using them now and replace them with a durable equivalent.
Note that these functions may be still usable : they generate warning that help tracking their usage in the log. To eradicate their usage, watch the logs, and update any deprecated warning. This way, the code won't be stuck when the function is actually removed from PHP.
<?php
// This is the current function
list($day, $month, $year) = explode('/', '08/06/1995');
// This is deprecated
list($day, $month, $year) = split('/', '08/06/1995');
?>
Dangling Array References
[Since 0.8.4] - [ -P Structures/DanglingArrayReferences ] - [ Online docs ]
Always unset a referenced-variable used in a loop.
It is highly recommended to unset blind variables when they are set up as references after a loop.
<?php
$array = array(1,2,3,4);
foreach($array as &$a) {
$a += 1;
}
// This only unset the reference, not the value
unset($a);
// Dangling array problem
foreach($array as &$a) {
$a += 1;
}
//$array === array(3,4,5,6);
// This does nothing (apparently)
// $a is already a reference, even if it doesn't show here.
foreach($array as $a) {}
//$array === array(3,4,5,5);
?>
When omitting this step, the next loop that will also require this variable will deal with garbage values, and produce unexpected results.
See also No Dangling Reference, PHP foreach pass-by-reference: Do it right, or better not at all, How does PHP 'foreach' actually work? and References and foreach
ext/sqlsrv
[Since 0.8.4] - [ -P Extensions/Extsqlsrv ] - [ Online docs ]
Extension for Microsoft SQL Server Driver.
The SQLSRV extension allows you to access Microsoft SQL Server and SQL Azure databases when running PHP on Windows.
<?php
$serverName = 'serverName\sqlexpress';
$connectionInfo = array( 'Database'=>'dbName', 'UID'=>'username', 'PWD'=>'password' );
$conn = sqlsrv_connect( $serverName, $connectionInfo);
if( $conn === false ) {
die( print_r( sqlsrv_errors(), true));
}
$sql = 'INSERT INTO Table_1 (id, data) VALUES (?, ?)';
$params = array(1, 'some data');
$stmt = sqlsrv_query( $conn, $sql, $params);
if( $stmt === false ) {
die( print_r( sqlsrv_errors(), true));
}
?>
See also Microsoft SQL Server Driver and PHP Driver for SQL Server Support for LocalDB
Queries In Loops
[Since 0.8.4] - [ -P Structures/QueriesInLoop ] - [ Online docs ]
Avoid querying databases in a loop.
Querying an external database in a loop usually leads to performances problems. This is also called the 'n + 1 problem'.
This problem applies also to prepared statement : when such statement are called in a loop, they are slower than one-time large queries.
It is recommended to reduce the number of queries by making one query, and dispatching the results afterwards. This is true with SQL databases, graph queries, LDAP queries, etc.
<?php
// Typical N = 1 problem : there will be as many queries as there are elements in $array
$ids = array(1,2,3,5,6,10);
$db = new SQLite3('mysqlitedb.db');
// all the IDS are merged into the query at once
$results = $db->query('SELECT bar FROM foo WHERE id in ('.implode(',', $id).')');
while ($row = $results->fetchArray()) {
var_dump($row);
}
// Typical N = 1 problem : there will be as many queries as there are elements in $array
$ids = array(1,2,3,5,6,10);
$db = new SQLite3('mysqlitedb.db');
foreach($ids as $id) {
$results = $db->query('SELECT bar FROM foo WHERE id = '.$id);
while ($row = $results->fetchArray()) {
var_dump($row);
}
}
?>
This optimisation is not always possible : for example, some SQL queries may not be prepared, like DROP TABLE or DESC . UPDATE commands often update one row at a time, and grouping such queries may be counter-productive or unsafe.
This analysis looks for query calls inside loops, and within one functioncall.
See also and E N+1 PROBLEM IN ORMS SOLVING THE N+1 PROBLEM IN ORMS
Var Keyword
[Since 0.8.4] - [ -P Classes/OldStyleVar ] - [ Online docs ]
Var was used in PHP 4 to mark properties as public. Nowadays, new keywords are available : public, protected, private. Var is equivalent to public.
It is recommended to avoid using var, and explicitly use the new keywords.
<?php
class foo {
public $bar = 1;
// Avoid var
//var $bar = 1;
}
?>
See also and Visibility
Native Alias Functions Usage
[Since 0.8.4] - [ -P Functions/AliasesUsage ] - [ Online docs ]
PHP manual recommends to avoid function aliases.
Some PHP native functions have several names, and both may be used the same way. However, one of the names is the main name, and the others are aliases. Aliases may be removed or change or dropped in the future. Even if this is not forecast, it is good practice to use the main name, instead of the aliases.
<?php
// official way to count an array
$n = count($array);
// official way to count an array
$n = sizeof($array);
?>
Aliases are compiled in PHP, and do not provide any performances over the normal function.
Aliases are more likely to be removed later, but they have been around for a long time.
See also and List of function aliases
Uses Default Values
[Since 0.8.4] - [ -P Functions/UsesDefaultArguments ] - [ Online docs ]
Default values are provided to methods so as to make it convenient to use. However, with new versions, those values may change. For example, in PHP 5.4, htmlentities() switched from Latin1 to UTF-8 default encoding.
<?php
$string = Eu não sou o pão;
echo htmlentities($string);
// PHP 5.3 : Eu não sou o pão
// PHP 5.4 : Eu não sou o pão
// Stable across versions
echo htmlentities($string, 'UTF8');
?>
As much as possible, it is recommended to use explicit values in those methods, so as to prevent from being surprise at a future PHP evolution.
This analyzer tend to report a lot of false positives, including usage of count(). Count() indeed has a second argument for recursive counts, and a default value. This may be ignored safely.
Wrong Number Of Arguments
[Since 0.8.4] - [ -P Functions/WrongNumberOfArguments ] - [ Online docs ]
Those functioncalls are made with too many or too few arguments.
When the number arguments is wrong for native functions, PHP emits a warning.
When the number arguments is too small for custom functions, PHP raises an exception.
When the number arguments is too high for custom functions, PHP ignores the arguments. Such arguments should be handled with the variadic operator, or with func_get_args() family of functions.
<?php
echo strtoupper('This function is', 'ignoring arguments');
//Warning: `strtoupper() <https://www.php.net/strtoupper>`_ expects exactly 1 parameter, 2 given in Command line code on line 1
echo `strtoupper() <https://www.php.net/strtoupper>`_;
//Warning: `strtoupper() <https://www.php.net/strtoupper>`_ expects exactly 1 parameter, 0 given in Command line code on line 1
function foo($argument) {}
echo foo();
//Fatal error: Uncaught ArgumentCountError: Too few arguments to function foo(), 0 passed in /Users/famille/Desktop/analyzeG3/test.php on line 10 and exactly 1 expected in /Users/famille/Desktop/analyzeG3/test.php:3
echo foo('This function is', 'ignoring arguments');
?>
It is recommended to check the signature of the methods, and fix the arguments.
Hardcoded Passwords
[Since 0.8.4] - [ -P Functions/HardcodedPasswords ] - [ Online docs ]
Hardcoded passwords in the code.
Hardcoding passwords is a bad idea. Not only it make the code difficult to change, but it is an information leak. It is better to hide this kind of information out of the code.
<?php
$ftp_server = '300.1.2.3'; // yes, this doesn't exists, it's an example
$conn_id = ftp_connect($ftp_server);
// login with username and password
$login_result = ftp_login($conn_id, 'login', 'password');
?>
See also 10 GitHub Security Best Practices and Git How-To: Remove Your Password from a Repository
Unresolved Classes
[Since 0.8.4] - [ -P Classes/UnresolvedClasses ] - [ Online docs ]
The following classes are instantiated in the code, but their definition couldn't be found.
<?php
class Foo extends Bar {
private function foobar() {
// here, parent is not resolved, as Bar is not defined in the code.
return parent::$prop;
}
}
?>
Ellipsis Usage
[Since 0.8.4] - [ -P Php/EllipsisUsage ] - [ Online docs ]
Usage of the ellipsis keyword. The keyword is three dots : ... . It is also named variadic or splat operator.
It may be in function definitions, either in functioncalls.
... allows for packing or unpacking arguments into an array.
<?php
$args = [1, 2, 3];
foo(...$args);
// Identical to foo(1,2,3);
function bar(...$a) {
// Identical to : $a = `func_get_args() <https://www.php.net/func_get_args>`_;
}
?>
See also PHP RFC: Syntax for variadic functions, PHP 5.6 and the Splat Operator and Variable-length argument lists
Useless Constructor
[Since 0.8.4] - [ -P Classes/UselessConstructor ] - [ Online docs ]
Class constructor that have empty bodies are useless. They may be removed, if they are not called.
<?php
class X {
function __construct() {
// Do nothing
}
}
class Y extends X {
// Useful constructor, as it prevents usage of the parent
function __construct() {
// Do nothing
}
}
?>
Implements Is For Interface
[Since 0.8.4] - [ -P Classes/ImplementIsForInterface ] - [ Online docs ]
With class heritage, implements should be used for interfaces, and extends with classes.
PHP defers the implements check until execution : the code in example does lint, but won,t run.
<?php
class x {
function foo() {}
}
interface y {
function foo();
}
// Use implements with an interface
class z implements y {}
// Implements is for an interface, not a class
class z implements x {}
?>
Use const
[Since 0.8.4] - [ -P Constants/ConstRecommended ] - [ Online docs ]
The const keyword may be used to define constant, just like the define() function.
When defining a constant, it is recommended to use 'const' when the features of the constant are not dynamical (name or value are known at compile time).
This way, constant will be defined at compile time, and not at execution time.
<?php
//Do
const A = 1;
// Don't
define('A', 1);
?>
define() function is useful when the constant is not known at compile time, or when case sensitivity is necessary.
<?php
// Read $a in database or config file
define('A', $a);
// Read $a in database or config file
define('B', 1, true);
echo b;
?>
See also and Syntax
Unresolved Use
[Since 0.8.4] - [ -P Namespaces/UnresolvedUse ] - [ Online docs ]
The following use instructions cannot be resolved to a known class, interface, trait, constant or function. They should be dropped or fixed.
A known class, interface, trait, constant or function is defined in PHP (standard), an extension, a stub or the current code.
<?php
namespace A {
// class B is defined
class B {}
// class C is not defined
}
namespace X/Y {
use A/B; // This use is valid
use A/C; // This use point to nothing.
new B();
new C();
}
?>
Use expression are options for the current namespace.
See also and Using namespaces: Aliasing/Importing
Undefined Parent
[Since 0.8.4] - [ -P Classes/UndefinedParentMP ] - [ Online docs ]
List of properties and methods that are accessed using parent keyword but are not defined in the parent classes.
This may compile but, eventually yields a fatal error during execution.
<?php
class theParent {
// No bar() method
// private bar() method is not accessible to theChild
}
class theChild extends theParent {
function foo() {
// bar is defined in theChild, but not theParent
parent::bar();
}
function bar() {
}
}
?>
Note that if the parent is defined using extends someClass but someClass is not available in the tested code, it will not be reported : it may be in composer, another dependency, or just missing.
See also parent.
Undefined static:: Or self::
[Since 0.8.4] - [ -P Classes/UndefinedStaticMP ] - [ Online docs ]
The identified property or method are undefined. self and static refer to the current class, or one of its parent or trait.
<?php
class x {
static public function definedStatic() {}
private definedStatic = 1;
public function method() {
self::definedStatic();
self::undefinedStatic();
static::definedStatic;
static::undefinedStatic;
}
}
?>
See also and Late Static Bindings
Accessing Private
[Since 0.8.4] - [ -P Classes/AccessPrivate ] - [ Online docs ]
List of calls to private properties/methods that will compile but yield some fatal error upon execution.
<?php
class a {
private $a;
}
class b extends a {
function c() {
$this->a;
}
}
?>
Access Protected Structures
[Since 0.8.4] - [ -P Classes/AccessProtected ] - [ Online docs ]
It is not allowed to access protected properties, methods or constants from outside the class or its relatives.
<?php
class foo {
protected $bar = 1;
}
$foo = new Foo();
$foo->bar = 2;
?>
See also Visibility. and Understanding The Concept Of Visibility In Object Oriented PHP
Parent, Static Or Self Outside Class
[Since 0.8.4] - [ -P Classes/PssWithoutClass ] - [ Online docs ]
Parent, static and self keywords must be used within a class or a trait. They make no sense outside a class or trait scope, as self and static refers to the current class and parent refers to one of parent above.
PHP 7.0 and later detect some of their usage at compile time, and emits a fatal error.
<?php
class x {
const Y = 1;
function foo() {
// self is \x
echo self::Y;
}
}
const Z = 1;
// This lint but won't anymore
echo self::Z;
?>
Static may be used in a function or a closure, but not globally.
ext/0mq
[Since 0.8.4] - [ -P Extensions/Extzmq ] - [ Online docs ]
Extension ext/zmq for 0mq .
ØMQ is a software library that lets you quickly design and implement a fast message-based application.
<?php
// Example from https://github.com/kuying/ZeroMQ/blob/d80dcc3dc1c14a343ca90bbd656b98fd55366548/zguide/examples/PHP/msgqueue.php
/*
* Simple message queuing broker
* Same as request-reply broker but using QUEUE device
* @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
*/
$context = new ZMQContext();
// Socket facing clients
$frontend = $context->getSocket(ZMQ::SOCKET_ROUTER);
$frontend->bind(tcp://*:5559);
// Socket facing services
$backend = $context->getSocket(ZMQ::SOCKET_DEALER);
$backend->bind(tcp://*:5560);
// Start built-in device
new ZMQDevice($frontend, $backend);
?>
See also ZeroMQ and ZMQ
ext/memcache
[Since 0.8.4] - [ -P Extensions/Extmemcache ] - [ Online docs ]
Extension Memcache.
Memcache module provides handy procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.
<?php
$memcache = new Memcache;
$memcache->connect('localhost', 11211) or die ('Could not connect');
$version = $memcache->getVersion();
echo 'Server\'s version: '.$version.'<br/>';
$tmp_object = new stdClass;
$tmp_object->str_attr = 'test';
$tmp_object->int_attr = 123;
$memcache->set('key', $tmp_object, false, 10) or die ('Failed to save data at the server');
echo 'Store data in the cache (data will expire in 10 seconds)<br/>';
$get_result = $memcache->get('key');
echo 'Data from the cache:<br/>';
var_dump($get_result);
?>
See also Memcache on PHP and memcache on github
ext/memcached
[Since 0.8.4] - [ -P Extensions/Extmemcached ] - [ Online docs ]
Extension ext-memcached.
This extension uses the libmemcached library to provide an API for communicating with memcached servers. It also provides a session handler (`memcached`).
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$m->set('foo', 100);
var_dump($m->get('foo'));
?>
See also ext/memcached manual and memcached
Dynamic Function Call
[Since 0.8.4] - [ -P Functions/Dynamiccall ] - [ Online docs ]
Mark a functioncall made with a variable name.
<?php
// function definition
function foo() {}
// function name is in a variable, as a string.
$var = 'foo';
// dynamic call of a function
$var();
call_user_func($var);
?>
Has Variable Arguments
[Since 0.8.4] - [ -P Functions/VariableArguments ] - [ Online docs ]
Indicates if this function or method accept an arbitrary number of arguments, based on func_get_args(), func_get_arg() and func_num_args() usage.
<?php
// Fixed number of arguments
function fixedNumberOfArguments($a, $b) {
if (`func_num_args() <https://www.php.net/func_num_args>`_ > 2) {
$c = `func_get_args() <https://www.php.net/func_get_args>`_;
array_shift($c); // $a
array_shift($c); // $b
}
// do something
}
// Fixed number of arguments
function fixedNumberOfArguments($a, $b, $c = 1) {}
?>
Multiple Catch
[Since 0.8.4] - [ -P Structures/MultipleCatch ] - [ Online docs ]
Indicates if a try structure have several catch statement.
<?php
// This try has several catch
try {
doSomething();
} catch (RuntimeException $e) {
processRuntimeException();
} catch (OtherException $e) {
processOtherException();
}
?>
Dynamically Called Classes
[Since 0.8.4] - [ -P Classes/VariableClasses ] - [ Online docs ]
Indicates if a class is called dynamically.
<?php
// This class is called dynamically
class X {
const CONSTANTE = 1;
}
$classe = 'X';
$x = new $classe();
echo $x::CONSTANTE;
?>
Conditioned Function
[Since 0.8.4] - [ -P Functions/ConditionedFunctions ] - [ Online docs ]
Indicates if a function is defined only if a condition is met.
<?php
// This is a conditioned function.
// it only exists if the PHP binary doesn't have it already.
if (!function_exists('join')) {
function join($glue, $array) {
return implode($glue, $array);
}
}
?>
Conditioned Constants
[Since 0.8.4] - [ -P Constants/ConditionedConstants ] - [ Online docs ]
Indicates if a constant will be defined only if a condition is met.
<?php
if (time() > 1519629617) {
define('MY_CONST', false);
} else {
define('MY_CONST', time() - 1519629617);
}
?>
Is Generator
[Since 0.8.4] - [ -P Functions/IsGenerator ] - [ Online docs ]
Mark as such functions or methods that are using yield and yield from.
<?php
function generator() {
yield from generator2();
return 3;
}
function generator2() {
yield 1;
yield 2;
}
?>
See also and Generators overview
Try With Finally
[Since 0.8.4] - [ -P Structures/TryFinally ] - [ Online docs ]
Indicates if a try use a finally statement.
<?php
try {
$a = doSomething();
} catch (Throwable $e) {
// Fix the problem
} finally {
// remove $a anyway
unset($a);
}
?>
See also and Exceptions
Dereferencing String And Arrays
[Since 0.8.4] - [ -P Structures/DereferencingAS ] - [ Online docs ]
PHP allows the direct dereferencing of strings and arrays.
This was added in PHP 5.5. There is no need anymore for an intermediate variable between a string and array (or any expression generating such value) and accessing an index.
<?php
$x = array(4,5,6);
$y = $x[2] ; // is 6
May be replaced by
$y = array(4,5,6)[2];
$y = [4,5,6][2];
?>
list() May Omit Variables
[Since 0.8.4] - [ -P Structures/ListOmissions ] - [ Online docs ]
Simply omit any unused variable in a list() call.
list() is the only PHP function that accepts to have omitted arguments. If the following code makes no usage of a listed variable, just omit it.
<?php
// No need for '2', so no assignation
list ($a, , $b) = array(1, 2, 3);
// works with PHP 7.1 short syntax
[$a, , $b] = array(1, 2, 3);
// No need for '2', so no assignation
list ($a, $c, $b) = array(1, 2, 3);
?>
See also list.
See also and class
Or Die
[Since 0.8.4] - [ -P Structures/OrDie ] - [ Online docs ]
Classic old style failed error management.
<?php
// In case the connexion fails, this kills the current script
mysql_connect('localhost', $user, $pass) or die();
?>
Interrupting a script will leave the application with a blank page, will make your life miserable for testing. Just don't do that.
See also pg_last_error or
PDO::exec.
Constant Scalar Expressions
[Since 0.8.4] - [ -P Structures/ConstantScalarExpression ] - [ Online docs ]
Define constant with the result of static expressions. This means that constants may be defined with the const keyword, with the help of various operators but without any functioncalls.
This feature was introduced in PHP 5.6. It also supports array(), and expressions in arrays.
Those expressions (using simple operators) may only manipulate other constants, and all values must be known at compile time.
<?php
// simple definition
const A = 1;
// constant scalar expression
const B = A * 3;
// constant scalar expression
const C = [A ** 3, '3' => B];
?>
See also and Constant Scalar Expressions
Written Only Variables
[Since 0.8.4] - [ -P Variables/WrittenOnlyVariable ] - [ Online docs ]
Those variables are being written, but never read. This way, they are useless and should be removed, or read at some point.
<?php
// $a is used multiple times, but never read
$a = 'a';
$a .= 'b';
$b = 3;
//$b is actually read once
$a .= $b + 3;
?>
Must Return Methods
[Since 0.8.4] - [ -P Functions/MustReturn ] - [ Online docs ]
The following methods are expected to return a value that will be used later. Without return, they are useless.
Methods that must return are : __get(), __isset(), __sleep(), __toString(), __set_state(), __invoke(), __debugInfo().
Methods that may not return, but are often expected to : __call(), __callStatic().
<?php
class foo {
public function __isset($a) {
// returning something useful
return isset($this->$var[$a]);
}
public function __get($a) {
$this->$a++;
// not returning...
}
public function __call($name, $args) {
$this->$name(...$args);
// not returning anything, but that's OK
}
}
?>
Empty Instructions
[Since 0.8.4] - [ -P Structures/EmptyLines ] - [ Online docs ]
Empty instructions are part of the code that have no instructions.
This may be trailing semi-colon or empty blocks for if-then structures.
Comments that explains the reason of the situation are not taken into account.
<?php
$condition = 3;;;;
if ($condition) { }
?>
ext/imagick
[Since 0.8.4] - [ -P Extensions/Extimagick ] - [ Online docs ]
Extension Imagick for PHP.
Imagick is a native php extension to create and modify images using the ImageMagick API.
<?php
header('Content-type: image/jpeg');
$image = new Imagick('image.jpg');
// If 0 is provided as a width or height parameter,
// aspect ratio is maintained
$image->thumbnailImage(100, 0);
echo $image;
?>
See also Imagick for PHP and Imagick
ext/oci8
[Since 0.8.4] - [ -P Extensions/Extoci8 ] - [ Online docs ]
Extension ext/oci8.
OCI8 gives access Oracle Database 12c, 11g, 10g, 9i and 8i.
<?php
$conn = oci_connect('hr', 'welcome', 'localhost/XE');
if (!$conn) {
$e = oci_error();
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}
// Prepare the statement
$stid = oci_parse($conn, 'SELECT * FROM departments');
if (!$stid) {
$e = oci_error($conn);
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}
// Perform the logic of the query
$r = oci_execute($stid);
if (!$r) {
$e = oci_error($stid);
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}
// Fetch the results of the query
print '<table border='1'>' . PHP_EOL;
while ($row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS)) {
print '<tr>' . PHP_EOL;
foreach ($row as $item) {
print ' <td>' . ($item !== null ? htmlentities($item, ENT_QUOTES) : ' ') . '</td>' . PHP_EOL;
}
print '</tr>' . PHP_EOL;
}
print '</table>' . PHP_EOL;
oci_free_statement($stid);
oci_close($conn);
?>
See also Oracle OCI8 and Oracle
Overwritten Exceptions
[Since 0.8.4] - [ -P Exceptions/OverwriteException ] - [ Online docs ]
In catch blocks, it is good practice to avoid overwriting the incoming exception, as information about the exception will be lost.
<?php
try {
doSomething();
} catch (SomeException $e) {
// $e is overwritten
$e = new anotherException($e->getMessage());
throw $e;
} catch (SomeOtherException $e) {
// $e is chained with the next exception
$e = new Exception($e->getMessage(), 0, $e);
throw $e;
}
?>
Foreach Reference Is Not Modified
[Since 0.8.4] - [ -P Structures/ForeachReferenceIsNotModified ] - [ Online docs ]
Foreach statement may loop using a reference, especially when the loop has to change values of the array it is looping on.
In the spotted loop, reference are used but never modified. They may be removed.
<?php
$letters = range('a', 'z');
// $letter is not used here
foreach($letters as &$letter) {
$alphabet .= $letter;
}
// $letter is actually used here
foreach($letters as &$letter) {
$letter = strtoupper($letter);
}
?>
ext/imap
[Since 0.8.4] - [ -P Extensions/Extimap ] - [ Online docs ]
Extension ext/imap.
This extension operate with the IMAP protocol, as well as the NNTP, POP3 and local mailbox access methods.
<?php
$mbox = imap_open('{imap.example.org}', 'username', 'password', OP_HALFOPEN)
or die('can't connect: ' . imap_last_error());
$list = imap_list($mbox, '{imap.example.org}', '*');
if (is_array($list)) {
foreach ($list as $val) {
echo imap_utf7_decode($val) . PHP_EOL;
}
} else {
echo 'imap_list failed: ' . imap_last_error() . PHP_EOL;
}
imap_close($mbox);?>
See also and IMAP
Overwritten Class Constants
[Since 0.8.4] - [ -P Classes/OverwrittenConst ] - [ Online docs ]
Those class constants are overwriting a parent class's constant. This may lead to confusion, as the value of the constant may change depending on the way it is called.
<?php
class foo {
const C = 1;
}
class bar extends foo {
const C = 2;
function x() {
// depending on the access to C, value is different.
print self::C.' '.static::C.' '.parent::C;
}
}
?>
Dynamic Class Constant
[Since 0.8.4] - [ -P Classes/DynamicConstantCall ] - [ Online docs ]
Dynamic calls to class constants.
Constant may be dynamically called with the constant() function.
<?php
// Dynamic access to 'E_ALL'
echo constant('E_ALL');
interface i {
const MY_CONSTANT = 1;
}
// Dynamic access to 'E_ALL'
echo constant('i::MY_CONSTANT');
?>
Dynamic Methodcall
[Since 0.8.4] - [ -P Classes/DynamicMethodCall ] - [ Online docs ]
Dynamic calls to class methods.
<?php
class x {
static public function foo() {}
public function bar() {}
}
$staticmethod = 'foo';
// dynamic static method call to x::foo()
x::$staticmethod();
$method = 'bar';
// dynamic method call to bar()
$object = new x();
$object->$method();
?>
Dynamic New
[Since 0.8.4] - [ -P Classes/DynamicNew ] - [ Online docs ]
Dynamic instantiation of classes. It happens when the name of the class is an executable expression, and, as such, only known at execution time.
<?php
$classname = foo();
$object = new $classname();
$object = new (foo());
?>
Dynamic Property
[Since 0.8.4] - [ -P Classes/DynamicPropertyCall ] - [ Online docs ]
Dynamic access to class property. This is when the the name of the property is stored in a variable (or other container), rather than statically provided.
<?php
class x {
static public $foo = 1;
public $bar = 2;
}
$staticproperty = 'foo';
// dynamic static property call to x::$foo
echo x::${$staticproperty};
$property = 'bar';
// dynamic property call to bar()
$object = new x();
$object->$property = 4;
?>
See also and class
Don't Change Incomings
[Since 0.8.4] - [ -P Structures/NoChangeIncomingVariables ] - [ Online docs ]
PHP hands over a lot of information using special variables like $_GET, $_POST, etc... Modifying those variables and those values inside variables means that the original content is lost, while it will still look like raw data, and, as such, will be untrustworthy.
<?php
// filtering and keeping the incoming value.
$_DATA'id'] = (int) $_GET['id'];
// filtering and changing the incoming value.
$_GET['id'] = strtolower($_GET['id']);
?>
It is recommended to put the modified values in another variable, and keep the original one intact.
Dynamic Classes
[Since 0.8.4] - [ -P Classes/DynamicClass ] - [ Online docs ]
Dynamic calls of classes.
<?php
class x {
static function staticMethod() {}
}
$class = 'x';
$class::staticMethod();
?>
Compared Comparison
[Since 0.8.4] - [ -P Structures/ComparedComparison ] - [ Online docs ]
Usually, comparison are sufficient, and it is rare to have to compare the result of comparison. Check if this two-stage comparison is really needed.
<?php
if ($a === strpos($string, $needle) > 2) {}
// the expression above apply precedence :
// it is equivalent to :
if (($a === strpos($string, $needle)) > 2) {}
?>
See also and Operators Precedence
Useless Return
[Since 0.8.4] - [ -P Functions/UselessReturn ] - [ Online docs ]
The spotted functions or methods have a return statement, but this statement is useless. This is the case for constructor and destructors, whose return value are ignored or inaccessible.
When return is void, and the last element in a function, it is also useless.
<?php
class foo {
function __construct() {
// return is not used by PHP
return 2;
}
}
function bar(&$a) {
$a++;
// The last return, when empty, is useless
return;
}
?>
Multiple Classes In One File
[Since 0.8.4] - [ -P Classes/MultipleClassesInFile ] - [ Online docs ]
It is regarded as a bad practice to store several classes in the same file. This is usually done to make life of __autoload() easier.
It is often unexpected to find class foo in the bar.php file. This is also the case for interfaces and traits.
<?php
// three classes in the same file
class foo {}
class bar {}
class foobar{}
?>
One good reason to have multiple classes in one file is to reduce include time by providing everything into one nice include.
See also Is it a bad practice to have multiple classes in the same file?.
File Uploads
[Since 0.8.4] - [ -P Structures/FileUploadUsage ] - [ Online docs ]
This code makes usage of file upload features of PHP.
Upload file feature is detected through the usage of specific functions :
<?php
$uploaddir = '/var/www/uploads/';
$uploadfile = $uploaddir . basename($_FILES['userfile']['name']);
echo '<pre>';
if (move_uploaded_file($_FILES['userfile']['tmp_name'], $uploadfile)) {
echo 'File is valid, and was successfully uploaded.'.PHP_EOL;
} else {
echo 'Possible file upload attack!'.PHP_EOL;
}
echo 'Here is some more debugging info:';
print_r($_FILES);
print '</pre>';
?>
See also and Handling file uploads
Unused Classes
[Since 0.8.4] - [ -P Classes/UnusedClass ] - [ Online docs ]
The following classes are never explicitly used in the code.
Note that this may be valid in case the current code is a library or framework, since it defines classes that are used by other (unprovided) codes.
Also, this analyzer may find classes that are, in fact, dynamically loaded.
<?php
class unusedClasss {}
class usedClass {}
$y = new usedClass();
?>
See also and class
ext/intl
[Since 0.8.4] - [ -P Extensions/Extintl ] - [ Online docs ]
Extension international.
Internationalization extension (further is referred as Intl) is a wrapper for ICU library, enabling PHP programmers to perform various locale-aware operations including but not limited to formatting, transliteration, encoding conversion, calendar operations, UCA-conformant collation, locating text boundaries and working with locale identifiers, timezones and graphemes.
<?php
$coll = new Collator('en_US');
$al = $coll->getLocale(Locale::ACTUAL_LOCALE);
echo Actual locale: $al\n;
$formatter = new NumberFormatter('en_US', NumberFormatter::DECIMAL);
echo $formatter->format(1234567);
?>
See also and Internationalization Functions
Dynamic Code
[Since 0.8.4] - [ -P Structures/DynamicCode ] - [ Online docs ]
List of instructions that were left during analysis, as they rely on dynamic data.
<?php
// Dynamic call to 'method';
$name = 'method';
$object->$name();
// Hard coded call to 'method';
$object->method();
?>
Any further analysis will need to start from here.
See also and Variable functions
Unpreprocessed Values
[Since 0.8.4] - [ -P Structures/Unpreprocessed ] - [ Online docs ]
Preprocessing values is the preparation of values before PHP executes the code.
There is no macro language in PHP, that prepares the code before compilation, bringing some comfort and short syntax. Most of the time, one uses PHP itself to preprocess data.
For example :
<?php
$days_en = 'monday,tuesday,wednesday,thursday,friday,saturday,sunday';
$days_zh = '星期－,星期二,星期三,星期四,星期五,星期六,星期日';
$days = explode(',', $lang === 'en' ? $days_en : $days_zh);
?>
could be written
<?php
if ($lang === 'en') {
$days = ['monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'];
} else {
$days = ['星期－', '星期二', '星期三', '星期四', '星期五', '星期六', '星期日'];
}
?>
and avoid preprocessing the string into an array first.
Preprocessing could be done anytime the script includes all the needed values to process the expression.
This is a micro-optimisation, in particular when the expression is used once.
ext/pspell
[Since 0.8.4] - [ -P Extensions/Extpspell ] - [ Online docs ]
Extension pspell.
These functions allow you to check the spelling of a word and offer suggestions.
<?php
$pspell_link = pspell_new('en');
if (pspell_check($pspell_link, 'testt')) {
echo 'This is a valid spelling';
} else {
echo 'Sorry, wrong spelling';
}
?>
See also Pspell and pspell
No Direct Access
[Since 0.8.4] - [ -P Structures/NoDirectAccess ] - [ Online docs ]
This expression protects files against direct access. It will kill the process if it realizes this is not supposed to be directly accessed.
Those expressions are used in applications and framework, to prevent direct access to definition files.
<?php
// CONSTANT_EXEC is defined in the main file of the application
defined('CONSTANT_EXEC') or die('Access not allowed'); : Constant used!
?>
ext/opcache
[Since 0.8.4] - [ -P Extensions/Extopcache ] - [ Online docs ]
Extension opcache.
OPcache improves PHP performance by storing precompiled script bytecode in shared memory, thereby removing the need for PHP to load and parse scripts on each request.
<?php
echo opcache_compile_file('/var/www/index.php');
print_r(opcache_get_status());
?>
See also and OPcache functions
ext/expect
[Since 0.8.4] - [ -P Extensions/Extexpect ] - [ Online docs ]
Extension Expect.
This extension allows to interact with processes through PTY . You may consider using the expect:// wrapper with the filesystem functions which provide a simpler and more intuitive interface.
<?php
ini_set('expect.loguser', 'Off');
$stream = fopen('expect://ssh root@remotehost uptime', 'r');
$cases = array (
array (0 => 'password:', 1 => PASSWORD)
);
switch (expect_expectl ($stream, $cases)) {
case PASSWORD:
fwrite ($stream, 'password'.PHP_EOL);
break;
default:
die ('Error was occurred while connecting to the remote host!'.PHP_EOL);
}
while ($line = fgets($stream)) {
print $line;
}
fclose ($stream);
?>
See also and expect
Undefined Properties
[Since 0.8.4] - [ -P Classes/UndefinedProperty ] - [ Online docs ]
List of properties that are not explicitly defined in the class, its parents or traits.
<?php
class foo {
// property definition
private bar = 2;
function foofoo() {
// $this->bar is defined in the class
// $this->barbar is NOT defined in the class
return $this->bar + $this->barbar;
}
}
?>
It is possible to spot unidentified properties by using the PHP's magic methods __get and __set . Even if the class doesn't use magic methods, any call to an undefined property will be directed to those methods, and they can be used as a canary, warning that the code is missing a definition.
<?php
trait NoUnefinedProperties {
function __get($name) {
assert(false, "Attempt to read the $name property, on the class ".__CLASS__;
}
function __set($name, $value) {
assert(false, "Attempt to read the $name property, on the class ".__CLASS__;
}
}
?>
In PHP 8.2, undefined properties are reported as deprecated. They will be a Fatal Error in PHP 9.0.
See also and Properties
ext/gettext
[Since 0.8.4] - [ -P Extensions/Extgettext ] - [ Online docs ]
Extension Gettext.
The gettext functions implement an NLS (Native Language Support) API which can be used to internationalize your PHP applications.
<?php
// Set language to German
putenv('LC_ALL=de_DE');
setlocale(LC_ALL, 'de_DE');
// Specify location of translation tables
bindtextdomain('myPHPApp', './locale');
// Choose domain
textdomain('myPHPApp');
// Translation is looking for in ./locale/de_DE/LC_MESSAGES/myPHPApp.mo now
// Print a test message
echo gettext('Welcome to My PHP Application');
// Or use the alias _() for gettext()
echo _('Have a nice day');
?>
See also Gettext and ext/gettext
Short Open Tags
[Since 0.8.4] - [ -P Php/ShortOpenTagRequired ] - [ Online docs ]
Usage of short open tags is discouraged. The following files were found to be impacted by the short open tag directive at compilation time. They must be reviewed to ensure no <? tags are found in the code.
Strict Comparison With Booleans
[Since 0.8.4] - [ -P Structures/BooleanStrictComparison ] - [ Online docs ]
Strict comparisons prevent mistaking an error with a false.
Boolean values may be easily mistaken with other values, especially when the function may return integer or boolean as a normal course of action.
It is encouraged to use strict comparison === or !== when booleans are involved in a comparison.
<?php
// distinguish between : $b isn't in $a, and, $b is at the beginning of $a
if (strpos($a, $b) === 0) {
doSomething();
}
// DOES NOT distinguish between : $b isn't in $a, and, $b is at the beginning of $a
if (strpos($a, $b)) {
doSomething();
}
// will NOT mistake 1 and true
$a = array(0, 1, 2, true);
if (in_array($a, true, true)) {
doSomething();
}
// will mistake 1 and true
$a = array(0, 1, 2, true);
if (in_array($a, true)) {
doSomething();
}
?>
switch() structures always uses `==` comparisons. Since PHP 8.0, it is possible to use match() to have strict comparisons. This is not reported by this analysis, as every switch should be refactored.
Native functions in_array(), array_keys() and array_search() have a third parameter to make it use strict comparisons.
Lone Blocks
[Since 0.8.4] - [ -P Structures/LoneBlock ] - [ Online docs ]
Any grouped code without a commanding structure is useless.
Blocks are compulsory when defining a structure, such as a class or a function. They are most often used with flow control instructions, like if then or switch.
Blocks are also valid syntax that group several instructions together, though they have no effect at all, except confuse the reader. Most often, it is a ruin from a previous flow control instruction, whose condition was removed or commented. They should be removed.
<?php
// Lone block
//foreach($a as $b)
{
$b++;
}
?>
$this Is Not For Static Methods
[Since 0.8.4] - [ -P Classes/ThisIsNotForStatic ] - [ Online docs ]
Static methods shouldn't use $this variable.
$this variable represents an object, the current object. It is not compatible with a static method, which may operate without any object.
While executing a static method, $this is actually set to NULL.
<?php
class foo {
static $staticProperty = 1;
// Static methods should use static properties
static public function `count() <https://www.php.net/count>`_ {
return self::$staticProperty++;
}
// Static methods can't use $this
static public function bar() {
return $this->a; // No $this usage in a static method
}
}
?>
See also Static Keyword.
Super Global Usage
[Since 0.8.4] - [ -P Php/SuperGlobalUsage ] - [ Online docs ]
Spot usage of Super global variables, such as $_GET, $_POST or $_REQUEST.
<?php
echo htmlspecialchars($_GET['name'], UTF-8);
?>
See also and Superglobals
Global Usage
[Since 0.8.4] - [ -P Structures/GlobalUsage ] - [ Online docs ]
List usage of globals variables, with global keywords or direct access to $GLOBALS.
<?php
$a = 1; /* global scope */
function test()
{
echo $a; /* reference to local scope variable */
}
test();
?>
It is recommended to avoid using global variables, at it makes it very difficult to track changes in values across the whole application.
See also and Variable scope
Logical Should Use Symbolic Operators
[Since 0.8.4] - [ -P Php/LogicalInLetters ] - [ Online docs ]
Logical operators come in two flavors : and / &&, || / or, ^ / xor. However, they are not exchangeable, as && and and have different precedence.
<?php
// Avoid lettered operator, as they have lower priority than expected
$a = $b and $c;
// $a === 3 because equivalent to ($a = $b) and $c;
// safe way to write the above :
$a = ($b and $c);
$a = $b && $c;
// $a === 1
?>
It is recommended to use the symbol operators, rather than the letter ones.
See also Logical Operators.
Could Use self
[Since 0.8.4] - [ -P Classes/ShouldUseSelf ] - [ Online docs ]
self keyword refers to the current class, or any of its parents. Using it is just as fast as the full class name, it is as readable and it is will not be changed upon class or namespace change.
It is also routinely used in traits : there, self represents the class in which the trait is used, or the trait itself.
<?php
class x {
const FOO = 1;
public function bar() {
return self::FOO;
// same as return x::FOO;
}
}
?>
See also and Scope Resolution Operator (::)
Catch Overwrite Variable
[Since 0.8.4] - [ -P Structures/CatchShadowsVariable ] - [ Online docs ]
The try/catch structure uses some variables that are also in use in this scope. In case of a caught exception, the exception will be put in the catch variable, and overwrite the current value, loosing some data.
<?php
// variables and caught exceptions are distinct
$argument = 1;
try {
methodThatMayRaiseException($argument);
} (Exception $e) {
// here, $e has been changed to an exception.
}
// variables and caught exceptions are overlapping
$e = 1;
try {
methodThatMayRaiseException();
} (Exception $e) {
// here, $e has been changed to an exception.
}
?>
It is recommended to use another name for these catch variables.
Namespaces
[Since 0.8.4] - [ -P Namespaces/NamespaceUsage ] - [ Online docs ]
Inventory of all namespaces.
<?php
namespace My/Personal/Name;
class Name {}
?>
Deep Definitions
[Since 0.8.4] - [ -P Functions/DeepDefinitions ] - [ Online docs ]
Structures, such as functions, classes, interfaces, traits, enum, etc. may be defined anywhere in the code, including inside functions. This is legit code for PHP.
Since the availability of autoload, with spl_register_autoload(), there is no need for that kind of code. Structures should be defined, and accessible to the autoloading. Inclusions and deep definitions should be avoided, as they compel code to load some definitions, while autoloading will only load them if needed.
<?php
class X {
function init() {
// myFunction is defined when and only if X::init() is called.
if (!function_exists('myFunction'){
function myFunction($a) {
return $a + 1;
}
})
}
}
?>
Functions are excluded from autoload, but shall be gathered in libraries, and not hidden inside other code.
Constants definitions are tolerated inside functions : they may be used for avoiding repeat, or noting the usage of such function.
Definitions inside a if/then statement, that include PHP version check are accepted here.
See also and Autoloading Classes
File Is Not Definitions Only
[Since 0.8.4] - [ -P Files/NotDefinitionsOnly ] - [ Online docs ]
An included file should only provide definitions and declarations, or executable code : not both.
With definitions only files, their inclusion provide new features, and keep the current execution untouched, and in control of the flow.
<?php
// This whole script is a file
// It contains definitions and global code
class foo {
static public $foo = null;
}
//This can be a singleton creation
foo::$foo = new foo();
trait t {}
class bar {}
?>
Within this context, globals, use, and namespaces instructions are not considered a warning.
Repeated print()
[Since 0.8.4] - [ -P Structures/RepeatedPrint ] - [ Online docs ]
Always merge several print or echo in one call.
It is recommended to use echo with multiple arguments, or a concatenation with print, instead of multiple calls to print echo, when outputting several blob of text.
<?php
//Write :
echo 'a', $b, 'c';
print 'a' . $b . 'c';
//Don't write :
print 'a';
print $b;
print 'c';
?>
Avoid Parenthesis With Language Construct
[Since 0.8.4] - [ -P Structures/PrintWithoutParenthesis ] - [ Online docs ]
Avoid Parenthesis for language construct. Languages constructs are a few PHP native elements, that looks like functions but are not.
Among other distinction, those elements cannot be directly used as variable function call, and they may be used with or without parenthesis.
<?php
// normal usage of include
include 'file.php';
// This looks like a function and is not
include('file2.php');
?>
The usage of parenthesis actually give some feeling of comfort, it won't prevent PHP from combining those argument with any later operators, leading to unexpected results.
Even if most of the time, usage of parenthesis is legit, it is recommended to avoid them.
Objects Don't Need References
[Since 0.8.4] - [ -P Structures/ObjectReferences ] - [ Online docs ]
There is no need to add references to parameters for objects, as those are always passed by reference when used as arguments.
Reference operator is needed when the object are replaced inside the method with a new value (or a clone), as whole. Calls to methods or property modifications do not require extra reference.
Reference operator is also needed when one of the types is scalar : this include null, and the hidden null type : that is when the default value is null.
This rule applies to arguments in methods, and to foreach() blind variables.
<?php
$object = new stdClass();
$object->name = 'a';
foo($object);
print $object->name; // Name is 'b'
// No need to make $o a reference
function foo(&$o) {
$o->name = 'b';
}
// $o is assigned inside the function : the parameter must have a &, or the new object won't make it out of the foo3 scope
function foo3(&$o) {
$o = new stdClass;
}
$array = array($object);
foreach($array as &$o) { // No need to make this a reference
$o->name = 'c';
}
?>
See also and Passing by reference
Lost References
[Since 0.8.4] - [ -P Variables/LostReferences ] - [ Online docs ]
Either avoid references, or propagate them correctly.
When assigning a referenced variable with another reference, the initial reference is lost, while the intend was to transfer the content.
<?php
function foo(&$lostReference, &$keptReference)
{
$c = 'c';
// $lostReference was a reference to $bar, but now, it is a reference to $c
$lostReference =& $c;
// $keptReference was a reference to $bar : it is still now, though it contains the actual value of $c now
$keptReference = $c;
}
$bar = 'bar';
$bar2 = 'bar';
foo($bar, $bar2);
//displays bar c, instead of bar bar
print $bar. ' '.$bar2;
?>
Do not reassign a reference with another reference. Assign new content to the reference to change its value.
Constants Created Outside Its Namespace
[Since 0.8.4] - [ -P Constants/CreatedOutsideItsNamespace ] - [ Online docs ]
Constants Created Outside Its Namespace.
Using the define() function, it is possible to create constant outside their namespace, but using the fully qualified namespace.
<?php
namespace A\B {
// define A\B\C as 1
define('C', 1);
}
namespace D\E {
// define A\B\C as 1, while outside the A\B namespace
define('A\B\C', 1);
}
?>
However, this makes the code confusing and difficult to debug. It is recommended to move the constant definition to its namespace.
Fully Qualified Constants
[Since 0.8.4] - [ -P Namespaces/ConstantFullyQualified ] - [ Online docs ]
Constants defined with their namespace.
When defining constants with define() function, it is possible to include the actual namespace :
<?php
define('a\b\c', 1);
?>
However, the name should be fully qualified without the initial \. Here, \a\b\c constant will never be accessible as a namespace constant, though it will be accessible via the constant() function.
Also, the namespace will be absolute, and not a relative namespace of the current one.
Never Used Properties
[Since 0.8.4] - [ -P Classes/PropertyNeverUsed ] - [ Online docs ]
Properties that are never used. They are defined in a class or a trait, but they never actually used.
Properties are considered used when they are used locally, in the same class as their definition, or in a parent class : a parent class is always included with the current class.
On the other hand, properties which are defined in a class, but only used in children classes is considered unused, since children may also avoid using it.
<?php
class foo {
public $usedProperty = 1;
// Never used anywhere
public $unusedProperty = 2;
function bar() {
// Used internally
++$this->usedProperty;
}
}
class foo2 extends foo {
function bar2() {
// Used in child class
++$this->usedProperty;
}
}
// Used externally
++$this->usedProperty;
?>
No Real Comparison
[Since 0.8.4] - [ -P Type/NoRealComparison ] - [ Online docs ]
Avoid comparing decimal numbers with ==, ===, !==, !=. Real numbers have an error margin which is random, and makes it very difficult to match even if the compared value is a literal.
PHP uses an internal representation in base 2 : any number difficult to represent with this base (like 0.1 or 0.7) will have a margin of error.
<?php
$a = 1/7;
$b = 2.0;
// 7 * $a is a real, not an integer
var_dump( 7 * $a === 1);
// rounding error leads to wrong comparison
var_dump( (0.1 + 0.7) * 10 == 8);
// although
var_dump( (0.1 + 0.7) * 10);
// displays 8
// precision formula to use with reals. Adapt 0.0001 to your precision needs
var_dump( abs(((0.1 + 0.7) * 10) - 8) < 0.0001);
?>
Use precision formulas with abs() to approximate values with a given precision, or avoid reals altogether.
See also and Floating point numbers
Should Use Local Class
[Since 0.8.4] - [ -P Classes/ShouldUseThis ] - [ Online docs ]
Methods should use the defining class, or be functions.
Methods should use $this with another method or a property, or call parent:: . Static methods should call another static method, or a static property.
Methods which are overwritten by a child class are omitted : the parent class act as a default value for the children class, and this is correct.
<?php
class foo {
public function __construct() {
// This method should do something locally, or be removed.
}
}
class bar extends foo {
private $a = 1;
public function __construct() {
// Calling parent:: is sufficient
parent::__construct();
}
public function barbar() {
// This is acting on the local object
$this->a++;
}
public function barfoo($b) {
// This has no action on the local object. It could be a function or a closure where needed
return 3 + $b;
}
}
?>
Note that a method using a class constant is not considered as using the local class, for this analyzer.
Usage Of class_alias()
[Since 0.8.4] - [ -P Classes/ClassAliasUsage ] - [ Online docs ]
class_alias creates dynamically an alias for classes.
<?php
class foo { }
class_alias('foo', 'bar');
$a = new foo;
$b = new bar;
// the objects are the same
var_dump($a == $b, $a === $b);
var_dump($a instanceof $b);
// the classes are the same
var_dump($a instanceof foo);
var_dump($a instanceof bar);
var_dump($b instanceof foo);
var_dump($b instanceof bar);
?>
See also and class_alias
ext/apache
[Since 0.8.4] - [ -P Extensions/Extapache ] - [ Online docs ]
Extension Apache.
These functions are only available when running PHP as an Apache module.
<?php
$ret = apache_getenv(SERVER_ADDR);
echo $ret;
?>
See also Extension Apache and Apache server
ext/eaccelerator
[Since 0.8.4] - [ -P Extensions/Exteaccelerator ] - [ Online docs ]
Extension Eaccelerator.
eAccelerator is a free open-source PHP accelerator & optimizer.
DEPRECATED: This project is deprecated and does not work with anything newer than PHP 5.3.
See also Eaccelerator and eaccelerator/eaccelerato
ext/fpm
[Since 0.8.4] - [ -P Extensions/Extfpm ] - [ Online docs ]
Extension FPM, FastCGI Process Manager.
FPM (FastCGI Process Manager) is an alternative PHP FastCGI implementation with some additional features (mostly) useful for heavy-loaded sites.
<?php
echo $text;
fastcgi_finish_request( );
?>
See also and FastCGI Process Manager
No Direct Call To Magic Method
[Since 0.8.4] - [ -P Classes/DirectCallToMagicMethod ] - [ Online docs ]
PHP features magic methods, which are methods related to operators.
Magic methods, such as __get(), related to =, or __clone(), related to clone , are supposed to be used in an object environment, and not with direct call.
It is recommended to use the magic method with its intended usage, and not to call it directly. For example, typecast to string instead of calling the __toString() method.
<?php
// Write
print $x->a;
// instead of
print $x->__get('a');
class Foo {
private $b = secret;
public function __toString() {
return strtoupper($this->b);
}
}
$bar = new Foo();
echo (string) $bar;
?>
Accessing those methods in a static way is also discouraged.
See also and Magical PHP: __call
String May Hold A Variable
[Since 0.8.4] - [ -P Type/StringHoldAVariable ] - [ Online docs ]
Strings that contains a variable, yet are not interpolated.
Single quotes and Nowdoc syntax may include $ signs. They are treated as literals, and not replaced with a variable value.
However, there are some potential variables in those strings, making it possible for an error : the variable was forgotten and will be published as such. It is worth checking the content and make sure those strings are not variables.
<?php
$a = 2;
// Explicit variable, but literal effect is needed
echo '$a is '.$a;
// One of the variable has been forgotten
echo '$a is $a';
// $CAD is not a variable, rather a currency unit
$total = 12;
echo $total.' $CAD';
// $CAD is not a variable, rather a currency unit
$total = 12;
// Here, $total has been forgotten
echo <<<'TEXT'
$total $CAD
TEXT;
?>
Echo With Concat
[Since 0.8.4] - [ -P Structures/EchoWithConcat ] - [ Online docs ]
Optimize your echo 's by avoiding concatenating at echo time, but serving all argument separated. This will save PHP a memory copy.
If values, literals and variables, are small enough, this won't have visible impact. Otherwise, this is less work and less memory waste.
<?php
echo $a, ' b ', $c;
?>
instead of
<?php
echo $a . ' b ' . $c;
echo $a b $c;
?>
It is a micro-optimisation.
Unused Global
[Since 0.8.4] - [ -P Structures/UnusedGlobal ] - [ Online docs ]
A global keyword is used in a method, yet the variable is not actually used. This makes PHP import values for nothing, or may create interference
<?php
function foo() {
global bar;
return 1;
}
?>
Useless Global
[Since 0.8.4] - [ -P Structures/UselessGlobal ] - [ Online docs ]
Global are useless in two cases. First, on super-globals, which are always globals, like $_GET; secondly, on variables that are not used.
<?php
// $_POST is already a global : it is in fact a global everywhere
global $_POST;
// $unused is useless
function foo() {
global $used, $unused;
++$used;
}
?>
Also, PHP has superglobals, a special team of variables that are always available, whatever the context.
They are : $GLOBALS, $_SERVER, $_GET, $_POST, $_FILES, $_COOKIE, $_SESSION, $_REQUEST and $_ENV.
Preprocessable
[Since 0.8.4] - [ -P Structures/ShouldPreprocess ] - [ Online docs ]
The following expressions are made of literals or already known values : they may be fully calculated before running PHP.
<?php
// Building an array from a string
$name = 'PHP'.' '.'7.2';
// Building an array from a string
$list = explode(',', 'a,b,c,d,e,f');
// Calculating a power
$kbytes = $bytes / pow(2, 10);
// This will never change
$name = ucfirst(strtolower('PARIS'));
?>
By doing so, this will reduce the amount of work of PHP. This is a micro-optimisation, when this is used once, or the amount of work is small. It may be kept for readability.
Useless Final
[Since 0.8.4] - [ -P Classes/UselessFinal ] - [ Online docs ]
When a class is declared final, all of its methods are also final by default.
There is no need to declare them individually final.
<?php
final class foo {
// Useless final, as the whole class is final
final function method() { }
}
class bar {
// Useful final, as the whole class is not final
final function method() { }
}
?>
See also Final Keyword and When to declare final
Use Constant Instead Of Function
[Since 0.8.4] - [ -P Structures/UseConstant ] - [ Online docs ]
Some functioncalls have a constant equivalent, that is faster to execute than calling the function.
This applies to the following functions :
- pi() : replace with `M_PI`
- phpversion() : replace with `PHP_VERSION`
- php_sapi_name() : replace with `PHP_SAPI_NAME`
<?php
// recommended way
echo PHP_VERSION;
// slow version
echo php_version();
?>
See also and PHP why `pi() and M_PI
Resources Usage
[Since 0.8.4] - [ -P Structures/ResourcesUsage ] - [ Online docs ]
List of situations that are creating resources.
<?php
// This functioncall creates a resource to use
$fp = fopen('/tmp/file.txt', 'r');
if (!is_resource($fp)){
thrown new RuntimeException('Could not open file.txt');
}
?>
Useless Unset
[Since 0.8.4] - [ -P Structures/UselessUnset ] - [ Online docs ]
There are situations where trying to remove a variable is actually useless.
PHP ignores any command that tries to unset a global variable, a static variable, or a blind variable from a foreach loop.
This is different from the garbage collector, which is run on its own schedule. It is also different from an explicit unset, aimed at freeing memory early : those are useful.
<?php
function foo($a) {
// unsetting arguments is useless
unset($a);
global $b;
// unsetting global variable has no effect
unset($b);
static $c;
// unsetting static variable has no effect
unset($c);
foreach($d as &$e){
// unsetting a blind variable is useless
(unset) $e;
}
// Unsetting a blind variable AFTER the loop is good.
unset($e);
}
?>
See also and unset
Buried Assignation
[Since 0.8.4] - [ -P Structures/BuriedAssignation ] - [ Online docs ]
Those assignations are buried in the code, and placed in unexpected situations.
They are difficult to spot, and may be confusing. It is advised to place them in a more visible place.
<?php
// $b may be assigned before processing $a
$a = $c && ($b = 2);
// Display property p immeiately, but also, keeps the object for later
echo ($o = new x)->p;
// legit syntax, but the double assignation is not obvious.
for($i = 2, $j = 3; $j < 10; $j++) {
}
?>
No array_merge() In Loops
[Since 0.8.4] - [ -P Performances/ArrayMergeInLoops ] - [ Online docs ]
array_merge() is memory intensive : every call will duplicate the arguments in memory, before merging them.
To handle arrays that may be quite big, it is recommended to avoid using array_merge() in a loop. Instead, one should use array_merge() with as many arguments as possible, making the merge a on time call.
<?php
// A large multidimensional array
$source = ['a' => ['a', 'b', /*...*/],
'b' => ['b', 'c', 'd', /*...*/],
/*...*/
];
// Faster way
$b = array();
foreach($source as $key => $values) {
//Collect in an array
$b[] = $values;
}
// One call to array_merge
$b = call_user_func_array('array_merge', $b);
// or with variadic
$b = call_user_func('array_merge', ..$b);
// Fastest way (with above example, without checking nor data pulling)
$b = call_user_func_array('array_merge', array_values($source))
// or
$b = call_user_func('array_merge', ...array_values($source))
// Slow way to merge it all
$b = array();
foreach($source as $key => $values) {
$b = array_merge($b, $values);
}
?>
Note that array_merge_recursive() and file_put_contents() are affected and reported the same way.
See also and Speed up `array_merge()
Useless Parenthesis
[Since 0.8.4] - [ -P Structures/UselessParenthesis ] - [ Online docs ]
Situations where parenthesis are not necessary, and may be removed.
Parenthesis group several elements together, and allows for a more readable expression. They are used with logical and mathematical expressions. They are necessary when the precedence of the operators are not the intended execution order : for example, when an addition must be performed before the multiplication.
Sometimes, the parenthesis provide the same execution order than the default order : they are deemed useless, from the PHP point of view. Yet, they may add readability to the code. In special circumstances, they may also protect the code from evolution in the precedence of operators : for example, 1 + 2 . '.' . 3 + 4; has different results between PHP 8 and PHP 7.
<?php
if ( ($condition) ) {}
while( ($condition) ) {}
do $a++; while ( ($condition) );
switch ( ($a) ) {}
$y = (1);
($y) == (1);
f(($x));
// = has precedence over ==
($a = $b) == $c;
($a++);
// No need for parenthesis in default values
function foo($c = ( 1 + 2) ) {}
?>
See also and Operators Precedence
Shell Usage
[Since 0.8.4] - [ -P Structures/ShellUsage ] - [ Online docs ]
List of shell calls to system.
<?php
// Using backtick operator
$a = `ls -hla`;
// Using one of PHP native or extension functions
$a = shell_exec('ls -hla');
$b = \pcntl_exec('/path/to/command');
?>
See also shell_exec and Execution Operators
File Usage
[Since 0.8.4] - [ -P Structures/FileUsage ] - [ Online docs ]
The application makes usage of files on the system (read, write, delete, etc.).
Files usage is based on the usage of file functions.
<?php
$fp = fopen('/tmp/file.txt', 'w+');
// ....
?>
See also and filesystem
Mail Usage
[Since 0.8.4] - [ -P Structures/MailUsage ] - [ Online docs ]
Report usage of mail from PHP.
The analysis is based on mail() function and various classes used to send mail.
<?php
// The message
$message = Line 1\r\nLine 2\r\nLine 3;
// In case any of our lines are larger than 70 characters, we should use `wordwrap() <https://www.php.net/wordwrap>`_
$message = wordwrap($message, 70, \r\n);
// Send
mail('caffeinated@example.com', 'My Subject', $message);
?>
See also and mail
Dynamic Calls
[Since 0.8.4] - [ -P Structures/DynamicCalls ] - [ Online docs ]
List of dynamic calls. They will probably need to be reviewed manually.
<?php
$a = 'b';
// Dynamic call of a constant
echo constant($a);
// Dynamic variables
$$a = 2;
echo $b;
// Dynamic call of a function
$a('b');
// Dynamic call of a method
$object->$a('b');
// Dynamic call of a static method
A::$a('b');
?>
Unresolved Instanceof
[Since 0.8.4] - [ -P Classes/UnresolvedInstanceof ] - [ Online docs ]
The instanceof operator doesn't confirm if the compared class exists.
It checks if an variable is of a specific class. However, if the referenced class doesn't exist, because of a bug, a missed inclusion or a typo, the operator always fails, without a warning.
<?php
namespace X {
class C {}
// This is OK, as C is defined in X
if ($o instanceof C) { }
// This is not OK, as C is not defined in global
// instanceof respects namespaces and use expressions
if ($o instanceof \C) { }
// This is not OK, as undefinedClass
if ($o instanceof undefinedClass) { }
// This is not OK, as $class is now a full namespace. It actually refers to \c, which doesn't exist
$class = 'C';
if ($o instanceof $class) { }
}
?>
Make sure the following classes are well defined.
See also and Instanceof
Use PHP Object API
[Since 0.8.4] - [ -P Php/UseObjectApi ] - [ Online docs ]
OOP API is the modern version of the PHP API.
When PHP offers the alternative between procedural and OOP api for the same features, it is recommended to use the OOP API.
Often, this least to more compact code, as methods are shorter, and there is no need to bring the resource around. Lots of new extensions are directly written in OOP form too.
OOP / procedural alternatives are available for mysqli, tidy, cairo, finfo, and some others.
<?php
/// OOP version
$mysqli = new mysqli(localhost, my_user, my_password, world);
/* check connection */
if ($mysqli->connect_errno) {
printf(Connect failed: %s\n, $mysqli->connect_error);
exit();
}
/* Create table doesn't return a resultset */
if ($mysqli->query(CREATE TEMPORARY TABLE myCity LIKE City) === TRUE) {
printf(Table myCity successfully created.\n);
}
/* Select queries return a resultset */
if ($result = $mysqli->query(SELECT Name FROM City LIMIT 10)) {
printf(Select returned %d rows.\n, $result->num_rows);
/* free result set */
$result->close();
}
?>
<?php
/// Procedural version
$link = mysqli_connect(localhost, my_user, my_password, world);
/* check connection */
if (mysqli_connect_errno()) {
printf(Connect failed: %s\n, mysqli_connect_error());
exit();
}
/* Create table doesn't return a resultset */
if (mysqli_query($link, CREATE TEMPORARY TABLE myCity LIKE City) === TRUE) {
printf(Table myCity successfully created.\n);
}
?>
Unthrown Exception
[Since 0.8.4] - [ -P Exceptions/Unthrown ] - [ Online docs ]
These exceptions are defined in the code but never thrown. They are probably dead code.
Unused exceptions are code bloat, as they increase the size of the code without any purpose. They are also misleading, as other developers might come to the impression that there is a mechanism to handle the situation that the exception describe, yet they are generating a fatal error.
<?php
//This exception is defined but never used in the code.
class myUnusedException extends \Exception {}
//This exception is defined and used in the code.
class myUsedException extends \Exception {}
throw new myUsedException('I was called');
?>
Old Style __autoload()
[Since 0.8.4] - [ -P Php/oldAutoloadUsage ] - [ Online docs ]
Avoid __autoload(), only use spl_register_autoload().
__autoload() is deprecated since PHP 7.2 and possibly removed in later versions. spl_register_autoload() was introduced in PHP 5.1.0.
__autoload() may only be declared once, and cannot be modified later. This creates potential conflicts between libraries that try to set up their own autoloading schema.
On the other hand, spl_register_autoload() allows registering and unregistering multiple autoloading functions or methods.
<?php
// Modern autoloading.
function myAutoload($class){}
spl_register_autoload('myAutoload');
// Old style autoloading.
function __autoload($class){}
?>
Do not use the old __autoload() function, but rather the new spl_register_autoload() function.
See also and Autoloading Classe
Altering Foreach Without Reference
[Since 0.8.4] - [ -P Structures/AlteringForeachWithoutReference ] - [ Online docs ]
Foreach() loop that could use a reference as value.
When using a foreach loop that modifies the original source, it is recommended to use referenced variables, rather than access the original value with $source[$index].
Using references is then must faster, and easier to read.
<?php
// Using references in foreach
foreach($source as $key => &$value) {
$value = newValue($value, $key);
}
// Avoid foreach : use array_map
$source = array_walk($source, 'newValue');
// Here, $key MUST be the second argument or newValue
// Slow version to update the array
foreach($source as $key => &$value) {
$source[$key] = newValue($value, $key);
}
?>
array_walk() and array_map() are also alternative to prevent the use of foreach(), when $key is not used.
See also foreach.
Test Class
[Since 0.8.4] - [ -P Classes/TestClass ] - [ Online docs ]
Those are test classes, based on popular UT frameworks.
Use Pathinfo
[Since 0.8.4] - [ -P Php/UsePathinfo ] - [ Online docs ]
Use pathinfo() function instead of string manipulations.
pathinfo() is more efficient and readable and string functions.
<?php
$filename = '/path/to/file.php';
// With `pathinfo() <https://www.php.net/pathinfo>`_;
$details = pathinfo($filename);
print $details['extension']; // also capture php
// With string functions (other solutions possible)
$ext = substr($filename, - strpos(strreverse($filename), '.')); // Capture php
?>
When the path contains UTF-8 characters, pathinfo() may strip them. There, string functions are necessary.
Should Use Existing Constants
[Since 0.8.4] - [ -P Functions/ShouldUseConstants ] - [ Online docs ]
The following functions have related constants that should be used as arguments, instead of scalar literals, such as integers or strings.
<?php
// The file is read and new lines are ignored.
$lines = file('file.txt', FILE_IGNORE_NEW_LINES)
// What is this doing, with 2 ?
$lines = file('file.txt', 2);
?>
See also and Bitmask Constant Arguments in PHP
Hash Algorithms
[Since 0.8.4] - [ -P Php/HashAlgos ] - [ Online docs ]
There is a long but limited list of hashing algorithm available to PHP. The one found doesn't seem to be existing.
<?php
// This hash has existed in PHP. Check with hash_algos() if it is available on your system.
echo hash('ripmed160', 'The quick brown fox jumped over the lazy dog.');
// This hash doesn't exist
echo hash('ripemd160', 'The quick brown fox jumped over the lazy dog.');
?>
See also hash_algos.
ext/dio
[Since 0.8.4] - [ -P Extensions/Extdio ] - [ Online docs ]
Extension DIO : Direct Input Output.
PHP supports the direct io functions as described in the Posix Standard (Section 6) for performing I/O functions at a lower level than the C-Language stream I/O functions
<?php
$fd = dio_open('/dev/ttyS0', O_RDWR | O_NOCTTY | O_NONBLOCK);
dio_close($fd);
?>
See also and DIO
No Parenthesis For Language Construct
[Since 0.8.4] - [ -P Structures/NoParenthesisForLanguageConstruct ] - [ Online docs ]
Some PHP language constructs, such are include , require , include_once , require_once , print , echo don't need parenthesis. They accept parenthesis, but it is may lead to strange situations.
<?php
// This is an attempt to load 'foo.inc', or kill the script
include('foo.inc') or die();
// in fact, this is read by PHP as : include 1
// include 'foo.inc' or die();
?>
It it better to avoid using parenthesis with echo , print , return , throw , yield , yield from , include , require , include_once , require_once .
See also ON PHP LANGUAGE CONSTRUCTS AND PARENTHESES and include
No Hardcoded Path
[Since 0.8.4] - [ -P Structures/NoHardcodedPath ] - [ Online docs ]
It is not recommended to use hardcoded literals when designating files. Full paths are usually tied to one file system organization. As soon as the organisation changes or must be adapted to any external constraint, the path is not valid anymore.
Either use __FILE__ and __DIR__ to make the path relative to the current file; use a DOC_ROOT as a configuration constant that will allow the moving of the script to another folder; finally functions like sys_get_temp_dir() produce a viable temporary folder.
Relative paths are relative to the current execution directory, and not the current file. This means they may differ depending on the location of the start of the application, and are sensitive to chdir() and chroot() usage.
<?php
// This depends on the current executed script
file_get_contents('token.txt');
// Exotic protocols are ignored
file_get_contents('jackalope://file.txt');
// Some protocols are ignored : http, https, ftp, ssh2, php (with memory)
file_get_contents('http://www.php.net/');
file_get_contents('php://memory/');
// `glob() <https://www.php.net/glob>`_ with special chars * and ? are not reported
glob('./*/foo/bar?.txt');
// `glob() <https://www.php.net/glob>`_ without special chars * and ? are reported
glob('/foo/bar/');
?>
No Hardcoded Port
[Since 0.8.4] - [ -P Structures/NoHardcodedPort ] - [ Online docs ]
When connecting to a remove server, port is an important information. It is recommended to make this configurable (with constant or configuration), to as to be able to change this value without changing the code.
<?php
// Both configurable IP and hostname
$connection = ssh2_connect($_ENV['SSH_HOST'], $_ENV['SSH_PORT'], $methods, $callbacks);
// Both hardcoded IP and hostname
$connection = ssh2_connect('shell.example.com', 22, $methods, $callbacks);
if (!$connection) die('Connection failed');
?>
ext/phalcon
[Since 0.8.4] - [ -P Extensions/Extphalcon ] - [ Online docs ]
Extension Phalcon : High Performance PHP Framework.
Phalcon's autoload examples from the docs : Tutorial 1: Let’s learn by example
<?php
use Phalcon\Loader;
// ...
$loader = new Loader();
$loader->registerDirs(
[
../app/controllers/,
../app/models/,
]
);
$loader->register();
?>
See also and PhalconPHP
Use Constant As Arguments
[Since 0.8.4] - [ -P Functions/UseConstantAsArguments ] - [ Online docs ]
Some methods and functions are defined to be used with constants as arguments. Those constants are made to be meaningful and readable, keeping the code maintenable. It is recommended to use such constants as soon as they are documented.
<?php
// Turn off all error reporting
// 0 and -1 are accepted
error_reporting(0);
// Report simple running errors
error_reporting(E_ERROR | E_WARNING | E_PARSE);
// The first argument can be one of INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, or INPUT_ENV.
$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
// sort accepts one of SORT_REGULAR, SORT_NUMERIC, SORT_STRING, SORT_LOCALE_STRING, SORT_NATURAL
// SORT_FLAG_CASE may be added, and combined with SORT_STRING or SORT_NATURAL
sort($fruits);
?>
Here is the list of functions that use a unique PHP constant as argument :
+ array_change_key_case()
+ array_multisort()
+ array_unique()
+ count()
+ dns_get_record()
+ easter_days()
+ extract()
+ filter_input()
+ filter_var()
+ fseek()
+ get_html_translation_table()
+ gmp_div_q()
+ gmp_div_qr()
+ gmp_div_r()
+ html_entity_decode()
+ htmlspecialchars_decode()
+ http_build_query()
+ http_parse_cookie()
+ http_parse_params()
+ http_redirect()
+ http_support()
+ parse_ini_file()
+ parse_ini_string()
+ parse_url()
+ pathinfo()
+ pg_select()
+ posix_access()
+ round()
+ scandir()
+ socket_read()
+ str_pad()
+ trigger_error()
Here is the list of functions that use a combination of PHP native constants as argument.
+ arsort()
+ asort()
+ error_reporting()
+ filter_input()
+ filter_var()
+ get_html_translation_table()
+ htmlentities()
+ htmlspecialchars()
+ http_build_url()
+ jdtojewish()
+ krsort()
+ ksort()
+ pg_result_status()
+ phpcredits()
+ phpinfo()
+ preg_grep()
+ preg_match()
+ preg_split()
+ rsort()
+ runkit_import()
+ sort()
+ stream_socket_client()
+ stream_socket_server()
Implied If
[Since 0.8.4] - [ -P Structures/ImpliedIf ] - [ Online docs ]
It is confusing to emulate if/then with boolean operators.
It is possible to emulate a if/then structure by using the operators 'and' and 'or'. Since optimizations will be applied to them :
when the left operand of 'and' is false, the right one is not executed, as its result is useless;
when the left operand of 'or' is true, the right one is not executed, as its result is useless;
However, such structures are confusing. It is easy to misread them as conditions, and ignore an important logic step.
<?php
// Either connect, or die
mysql_connect('localhost', $user, $pass) or die();
// Defines a constant if not found.
defined('SOME_CONSTANT') and define('SOME_CONSTANT', 1);
// Defines a default value if provided is empty-ish
// Warning : this is
$user = $_GET['user'] || 'anonymous';
?>
It is recommended to use a real 'if then' structures, to make the condition readable.
Overwritten Literals
[Since 0.8.4] - [ -P Variables/OverwrittenLiterals ] - [ Online docs ]
The same variable is assigned a literal twice. It is possible that one of the assignation is too many.
This analysis doesn't take into account the distance between two assignations : it may report false positives when the variable is actually used for several purposes, and, as such, assigned twice with different values.
<?php
function foo() {
// Two assignations in a short sequence : one is too many.
$a = 1;
$a = 2;
for($i = 0; $i < 10; $i++) {
$a += $i;
}
$b = $a;
// New assignation. $a is now used as an array.
$a = array(0);
}
?>
Assign Default To Properties
[Since 0.8.4] - [ -P Classes/MakeDefault ] - [ Online docs ]
Properties may be assigned default values at declaration time. Such values may be later modified, if needed.
<?php
class foo {
private $propertyWithDefault = 1;
private $propertyWithoutDefault;
private $propertyThatCantHaveDefault;
public function __construct() {
// Skip this extra line, and give the default value above
$this->propertyWithoutDefault = 1;
// Static expressions are available to set up simple computation at definition time.
$this->propertyWithoutDefault = OtherClass::CONSTANT + 1;
// Arrays, just like scalars, may be set at definition time
$this->propertyWithoutDefault = [1,2,3];
// Objects or resources can't be made default. That is OK.
$this->propertyThatCantHaveDefault = fopen('/path/to/file.txt');
$this->propertyThatCantHaveDefault = new Fileinfo();
}
}
?>
Default values will save some instructions in the constructor, and makes the value obvious in the code.
See also and PHP Default parameters
No Public Access
[Since 0.8.4] - [ -P Classes/NoPublicAccess ] - [ Online docs ]
The properties below are declared with public access, but are never used publicly. They can be made protected or private.
<?php
class foo {
public $bar = 1; // Public, and used in public space
public $neverInPublic = 3; // Public, but never used in outside the class
function bar() {
$neverInPublic++;
}
}
$x = new foo();
$x->bar = 3;
$x->bar();
?>
Composer Usage
[Since 0.8.4] - [ -P Composer/UseComposer ] - [ Online docs ]
Mark the usage of composer, mostly by having a composer.json file.
See also and Composer
Composer's autoload
[Since 0.8.4] - [ -P Composer/Autoload ] - [ Online docs ]
Report if this code is using the autoload from Composer.
Should Chain Exception
[Since 0.8.4] - [ -P Structures/ShouldChainException ] - [ Online docs ]
Chain exception to provide more context.
When catching an exception and rethrowing another one, it is recommended to chain the exception : this means providing the original exception, so that the final recipient has a chance to track the origin of the problem. This doesn't change the thrown message, but provides more information.
Note : Chaining requires PHP > 5.3.0.
<?php
try {
throw new Exception('Exception 1', 1);
} catch (\Exception $e) {
throw new Exception('Exception 2', 2, $e);
// Chaining here.
}
?>
See also Exception::__construct and What are the best practices for catching and re-throwing exceptions?
Useless Interfaces
[Since 0.8.4] - [ -P Interfaces/UselessInterfaces ] - [ Online docs ]
The interfaces below are defined and are implemented by some classes.
However, they are never used to enforce an object's class in the code, using instanceof or in a type.
As they are currently used, those interfaces may be removed without change in behavior.
<?php
// only defined interface but never enforced
interface i {};
class c implements i {}
?>
Interfaces should be used in type or with the instanceof operator.
<?php
interface i {};
function foo(i $arg) {
// Now, $arg is always an 'i'
}
function bar($arg) {
if (!($arg instanceof i)) {
// Now, $arg is always an 'i'
}
}
?>
Undefined Interfaces
[Since 0.8.4] - [ -P Interfaces/UndefinedInterfaces ] - [ Online docs ]
Some typehints or instanceof that are relying on undefined interfaces or classes. They will always return false. Any condition based upon them are dead code.
<?php
class var implements undefinedInterface {
// If undefinedInterface is undefined, this code lints but doesn't run
}
if ($o instanceof undefinedInterface) {
// This is silent dead code
}
function foo(undefinedInterface $a) {
// This is dead code
// it will probably be discovered at execution
}
?>
See also Object interfaces, Type declarations and Instanceof
ext/apcu
[Since 0.8.4] - [ -P Extensions/Extapcu ] - [ Online docs ]
Extension APCU .
APCu is APC stripped of opcode caching. The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.
<?php
$bar = 'BAR';
apcu_add('foo', $bar);
var_dump(apcu_fetch('foo'));
echo \n;
$bar = 'NEVER GETS SET';
apcu_add('foo', $bar);
var_dump(apcu_fetch('foo'));
echo \n;
?>
See also APCU, ext/apcu and krakjoe/apcu
Double Instructions
[Since 0.8.4] - [ -P Structures/DoubleInstruction ] - [ Online docs ]
Twice the same call in a row. This might be a typo, and the second call is useless.
It may also be an non-idempotent method: that is, a method which has a different result when called with the same arguments. For example, rand()
<?php
// repetition of the same command, with the same effect each time.
$a = array_merge($b, $c);
$a = array_merge($b, $c);
// false positive : commands are identical, but the effect is compounded
$a = array_merge($a, $c);
$a = array_merge($a, $c);
?>
Should Use Prepared Statement
[Since 0.8.4] - [ -P Security/ShouldUsePreparedStatement ] - [ Online docs ]
Modern databases provides support for prepared statement : it separates the query from the processed data and raise significantly the security.
Building queries with concatenations is not recommended, though not always avoidable. When possible, use prepared statements.
<?php
/* Execute a prepared statement by passing an array of values */
$sql = 'SELECT name, colour, calories
FROM fruit
WHERE calories < :calories AND colour = :colour';
$sth = $conn->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150, ':colour' => 'red'));
$red = $sth->fetchAll();
?>
Same code, without preparation :
<?php
$sql = 'SELECT name, color, calories FROM fruit WHERE calories < '.$conn-quote(150).' AND colour = '.$conn->quotes('red').' ORDER BY name';
$sth = $conn->query($sql) as $row);
}
?>
See also Prepared Statements, PHP MySQLi Prepared Statements Tutorial to Prevent SQL Injection and The Best Way to Perform MYSQLI Prepared Statements in PHP
Print And Die
[Since 0.8.4] - [ -P Structures/PrintAndDie ] - [ Online docs ]
Die() also prints.
When stopping a script with die(), it is possible to provide a message as first argument, that will be displayed at execution. There is no need to make a specific call to print or echo.
<?php
// die may do both print and die.
echo 'Error message';
die();
// exit may do both print and die.
print 'Error message';
exit;
// exit cannot print integers only : they will be used as status report to the system.
print 'Error message';
exit 1;
?>
Unchecked Resources
[Since 0.8.4] - [ -P Structures/UncheckedResources ] - [ Online docs ]
Resources are created, but never checked before being used. This is not safe.
Always check that resources are correctly created before using them.
<?php
// always check that the resource is created correctly
$fp = fopen($d,'r');
if ($fp === false) {
throw new Exception('File not found');
}
$firstLine = fread($fp);
// This directory is not checked : the path may not exist and return false
$uncheckedDir = opendir($pathToDir);
while(readdir($uncheckedDir)) {
// do something()
}
// This file is not checked : the path may not exist or be unreadable and return false
$fp = fopen($pathToFile);
while($line = freads($fp)) {
$text .= $line;
}
// unsafe one-liner : using bzclose on an unchecked resource
bzclose(bzopen('file'));
?>
See also and resources
ext/trader
[Since 0.8.4] - [ -P Extensions/Exttrader ] - [ Online docs ]
Extension trader.
The trader extension is a free open source stock library based on TA-Lib. It's dedicated to trading software developers requiring to perform technical analysis of financial market data.
<?php
// get_data() reads the data from a source
var_dump(trader_avgprice(
get_data(open, $data0),
get_data(high, $data0),
get_data(low, $data0),
get_data(close, $data0)
));
?>
See also trader (PECL), 'TA-lib
ext/mailparse
[Since 0.8.4] - [ -P Extensions/Extmailparse ] - [ Online docs ]
Extension mailparse.
Mailparse is an extension for parsing and working with email messages. It can deal with RFC 822 (MIME) and RFC 2045 (MIME) compliant messages.
<?php
$mail = mailparse_msg_create();
mailparse_msg_parse($mail, $mailInString);
$parts = mailparse_msg_get_structure($mail);
foreach($parts as $part) {
$section = mailparse_msg_get_part($mail, $part);
$info = mailparse_msg_get_part_data($section);
}
?>
See also and Mailparse
ext/mail
[Since 0.8.4] - [ -P Extensions/Extmail ] - [ Online docs ]
Extension for mail.
The mail() function allows you to send mail.
<?php
// The message
$message = "Line 1\r\nLine 2\r\nLine 3";
// In case any of our lines are larger than 70 characters, we should use `wordwrap() <https://www.php.net/wordwrap>`_
$message = wordwrap($message, 70, "\r\n");
// Send
mail('caffeinated@example.com', 'My Subject', $message);
?>
See also and Mail related functions
No Hardcoded Ip
[Since 0.8.4] - [ -P Structures/NoHardcodedIp ] - [ Online docs ]
Do not leave hard coded IP in your code.
It is recommended to move such configuration in external files or databases, for each update.
This may also come handy when testing.
<?php
// This IPv4 is hardcoded.
$ip = '183.207.224.50';
// This IPv6 is hardcoded.
$ip = '2001:0db8:85a3:0000:0000:8a2e:0370:7334';
// This looks like an IP
$thisIsNotAnIP = '213.187.99.50';
$thisIsNotAnIP = '2133:1387:9393:5330';
?>
127.0.0.1 , ::1 and ::0 are omitted, and not considered as a violation.
See also Use of Hardcoded IPv4 Addresses and Never hard code sensitive information
Else If Versus Elseif
[Since 0.8.4] - [ -P Structures/ElseIfElseif ] - [ Online docs ]
Always use elseif instead of else and if.
"The keyword elseif SHOULD be used instead of else if so that all control keywords look like single words". Quoted from the PHP-FIG documentation
<?php
// Using elseif
if ($a == 1) { doSomething(); }
elseif ($a == 2) { doSomethingElseIf(); }
else { doSomethingElse(); }
// Using else if
if ($a == 1) { doSomething(); }
else if ($a == 2) { doSomethingElseIf(); }
else { doSomethingElse(); }
// Using else if, no {}
if ($a == 1) doSomething();
else if ($a == 2) doSomethingElseIf();
else doSomethingElse();
?>
See also and elseif/else if
Unset In Foreach
[Since 0.8.4] - [ -P Structures/UnsetInForeach ] - [ Online docs ]
Unset applied to the variables of a foreach loop are useless. Those variables are copies and not the actual value. Even if the value is a reference, unsetting it has no effect on the original array : the only effect may be indirect, on elements inside an array, or on properties inside an object.
<?php
// When unset is useless
$array = [1, 2, 3];
foreach($array as $a) {
unset($a);
}
print_r($array); // still [1, 2, 3]
foreach($array as $b => &$a) {
unset($a);
}
print_r($array); // still [1, 2, 3]
// When unset is useful
$array = [ [ 'c' => 1] ]; // Array in array
foreach($array as &$a) {
unset(&$a['c']);
}
print_r($array); // now [ ['c' => null] ]
?>
Could Be Static
[Since 0.8.4] - [ -P Structures/CouldBeStatic ] - [ Online docs ]
This global is only used in one function or method. It may be called 'static', instead of global. This allows you to keep the value between call to the function, but will not be accessible outside this function.
<?php
function foo( ) {
static $variableIsReservedForX; // only accessible within foo( ), even between calls.
global $variableIsGlobal; // accessible everywhere in the application
}
?>
Multiple Class Declarations
[Since 0.8.4] - [ -P Classes/MultipleDeclarations ] - [ Online docs ]
It is possible to declare several times the same class in the code. PHP will not mention it until execution time, since declarations may be conditional.
<?php
$a = 1;
// Conditional declaration
if ($a == 1) {
class foo {
function method() { echo 'class 1';}
}
} else {
class foo {
function method() { echo 'class 2';}
}
}
(new foo())->method();
?>
It is recommended to avoid declaring several times the same class in the code. The best practice is to separate them with namespaces, they are for here for that purpose. In case those two classes are to be used interchangeably, the best is to use an abstract class or an interface.
See also and class
Empty Namespace
[Since 0.8.4] - [ -P Namespaces/EmptyNamespace ] - [ Online docs ]
Declaring a namespace in the code and not using it for structure declarations or global instructions is useless.
Using simple style :
<?php
namespace Y;
class foo {}
namespace X;
// This is useless
?>
Using bracket-style syntax :
<?php
namespace X {
// This is useless
}
namespace Y {
class foo {}
}
?>
Could Use Short Assignation
[Since 0.8.4] - [ -P Structures/CouldUseShortAssignation ] - [ Online docs ]
Use short assignment operator, to speed up code, and keep syntax clear.
Some operators, like * or +, have a compact and fast 'do-and-assign' version. They looks like a compacted version for = and the operator. This syntax is good for readability, and saves some memory in the process.
Depending on the operator, not all permutations of arguments are possible.
Addition and short assignation of addition have a different set of features when applied to arrays. Do not exchange one another in that case.
<?php
$a = 10 + $a;
$a += 10;
$b = $b - 1;
$b -= 1;
$c = $c * 2;
$c *= 2;
$d = $d / 3;
$d /= 3;
$e = $e % 4;
$e %= 4;
$f = $f | 5;
$f |= 5;
$g = $g & 6;
$g &= 6;
$h = $h ^ 7;
$h ^= 7;
$i = $i >> 8;
$i >>= 8;
$j = $j << 9;
$j <<= 9;
// PHP 7.4 and more recent
$l = $l ?? 'value';
$l ??= 'value';
?>
Short operators are faster than the extended version, though it is a micro-optimization.
See also and Assignation Operators
Useless Abstract Class
[Since 0.8.4] - [ -P Classes/UselessAbstract ] - [ Online docs ]
Those classes are marked 'abstract' and they are never extended. This way, they won't be instantiated nor used.
Abstract classes that have only static methods are omitted here : one usage of such classes are Utilities classes, which only offer static methods.
<?php
// Never extended class : this is useless
abstract class foo {}
// Extended class
abstract class bar {
public function barbar() {}
}
class bar2 extends bar {}
// Utility class : omitted here
abstract class bar {
public static function barbar() {}
}
?>
Scalar Typehint Usage
[Since 0.8.4] - [ -P Php/ScalarTypehintUsage ] - [ Online docs ]
Spot usage of scalar type hint : int , float , boolean and string .
Scalar typehint are PHP 7.0 and more recent. Some, like object , is 7.2.
Scalar typehint were not supported in PHP 5 and older. Then, the typehint is treated as a class name.
<?php
function withScalarTypehint(string $x) {}
function withoutScalarTypehint(someClass $x) {}
?>
See also PHP RFC: Scalar Type Hints and Type declarations
Return Typehint Usage
[Since 0.8.4] - [ -P Php/ReturnTypehintUsage ] - [ Online docs ]
Spot usage of return typehint. It is a PHP 7.0 feature.
Return typehint were introduced in PHP 7.0, and are backward incompatible with PHP 5.x.
<?php
function foo($a) : stdClass {
return new \stdClass();
}
?>
See also RFC: Return Type Declarations and Return Type Declarations
ext/ob
[Since 0.8.4] - [ -P Extensions/Extob ] - [ Online docs ]
Extension Output Buffering Control.
The Output Control functions allow you to control when output is sent from the script.
<?php
`ob_start() <https://www.php.net/ob_start>`_;
echo Hello\n;
setcookie(cookiename, cookiedata);
`ob_end_flush() <https://www.php.net/ob_end_flush>`_;
?>
See also and Output Buffering Control
Static Loop
[Since 0.8.4] - [ -P Structures/StaticLoop ] - [ Online docs ]
Static loop may be preprocessed.
It looks like the following loops are static : the same code is executed each time, without taking into account loop variables.
<?php
// Static loop
$total = 0;
for($i = 0; $i < 10; $i++) {
$total += $i;
}
// The above loop may be replaced by (with some math help)
$total = 10 * (10 + 1) / 2;
// Non-Static loop (the loop depends on the size of the array)
$n = count($array);
for($i = 0; $i < $n; $i++) {
$total += $i;
}
?>
It is possible to create loops that don't use any blind variables, though this is fairly rare. In particular, calling a method may update an internal pointer, like next() or SimpleXMLIterator::next() .
It is recommended to turn a static loop into an expression that avoid the loop. For example, replacing the sum of all integers by the function $n * ($n + 1) / 2 , or using array_sum().
This analysis doesn't detect usage of variables with compact .
Pre-increment
[Since 0.8.4] - [ -P Performances/PrePostIncrement ] - [ Online docs ]
When possible, use the pre-increment operator ( ++$i or --$i ) instead of the post-increment operator ( $i++ or $i-- ).
The latter needs an extra memory allocation that costs about 10% of performances.
<?php
// ++$i should be preferred over $i++, as current value is not important
for($i = 0; $i <10; ++$i) {
// do Something
}
// ++$b and $b++ have different impact here, since $a will collect $b + 1 or $b, respectively.
$a = $b++;
?>
This is a micro-optimisation. However, its usage is so widespread, including within loops, that it may eventually have an significant impact on execution time. As such, it is recommended to adopt this rule, and only consider changing legacy code as they are refactored for other reasons.
Only Variable Returned By Reference
[Since 0.8.4] - [ -P Structures/OnlyVariableReturnedByReference ] - [ Online docs ]
Function can't return literals by reference.
When a function returns a reference, it is only possible to return variables, properties or static properties.
Anything else, like literals or static expressions, yield a warning at execution time.
<?php
// Can't return a literal number
function &foo() {
return 3 + `rand() <https://www.php.net/rand>`_;
}
// bar must return values that are stored in a
function &bar() {
$a = 3 + `rand() <https://www.php.net/rand>`_;
return $a;
}
?>
ext/geoip
[Since 0.8.4] - [ -P Extensions/Extgeoip ] - [ Online docs ]
Extension geoip for PHP.
The GeoIP extension allows the localisation of an IP address.
<?php
$org = geoip_org_by_name('www.example.com');
if ($org) {
echo 'This host IP is allocated to: ' . $org;
}
?>
See also and GeoIP
ext/event
[Since 0.8.4] - [ -P Extensions/Extevent ] - [ Online docs ]
Extension event.
This is an extension to efficiently schedule I/O, time and signal based events using the best I/O notification mechanism available for specific platform. This is a port of libevent to the PHP infrastructure.
<?php
// Read callback
function readcb($bev, $base) {
//$input = $bev->input; //$bev->getInput();
//$pos = $input->search('TTP');
$pos = $bev->input->search('TTP');
while (($n = $bev->input->remove($buf, 1024)) > 0) {
echo $buf;
}
}
// Event callback
function eventcb($bev, $events, $base) {
if ($events & EventBufferEvent::CONNECTED) {
echo 'Connected.';
} elseif ($events & (EventBufferEvent::ERROR | EventBufferEvent::EOF)) {
if ($events & EventBufferEvent::ERROR) {
echo 'DNS error: ', $bev->getDnsErrorString(), PHP_EOL;
}
echo 'Closing'.PHP_EOL;
$base->exit();
exit('Done'.PHP_EOL);
}
}
if ($argc != 3) {
echo <<<EOS
Trivial HTTP 0.x client
Syntax: php {$argv[0]} [hostname] [resource]
Example: php {$argv[0]} www.google.com /
EOS;
exit();
}
$base = new EventBase();
$dns_base = new EventDnsBase($base, TRUE); // We'll use async DNS resolving
if (!$dns_base) {
exit('Failed to init DNS Base'.PHP_EOL);
}
$bev = new EventBufferEvent($base, /* use internal socket */ NULL,
EventBufferEvent::OPT_CLOSE_ON_FREE | EventBufferEvent::OPT_DEFER_CALLBACKS,
'readcb', /* writecb */ NULL, 'eventcb'
);
if (!$bev) {
exit('Failed creating bufferevent socket'.PHP_EOL);
}
//$bev->setCallbacks('readcb', /* writecb */ NULL, 'eventcb', $base);
$bev->enable(Event::READ | Event::WRITE);
$output = $bev->output; //$bev->getOutput();
if (!$output->add(
'GET '.$argv[2].' HTTP/1.0'."\r\n".
'Host: '.$argv[1]."\r\n".
'Connection: Close'.\r\n\r\n
)) {
exit('Failed adding request to output buffer\n');
}
if (!$bev->connectHost($dns_base, $argv[1], 80, EventUtil::AF_UNSPEC)) {
exit('Can\'t connect to host '.$argv[1].PHP_EOL);
}
$base->dispatch();
?>
See also Event and libevent
ext/amqp
[Since 0.8.4] - [ -P Extensions/Extamqp ] - [ Online docs ]
Extension amqp .
PHP AMQP Binding Library`. This is an interface with the `RabbitMQ AMQP client library. It is a C language AMQP client library for use with version 2.0 and more recent of the RabbitMQ broker.
<?php
$cnn = new AMQPConnection();
$cnn->connect();
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
$ch = new AMQPChannel($cnn);
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
$ch = new AMQPChannel($cnn);
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
$ch = null;
echo 'Used channels: ', $cnn->getUsedChannels(), PHP_EOL;
?>
See also and PHP AMQP Binding Library
ext/gearman
[Since 0.8.4] - [ -P Extensions/Extgearman ] - [ Online docs ]
Extension Gearman.
Gearman is a generic application framework for farming out work to multiple machines or processes.
<?php
# Create our client object.
$gmclient= new GearmanClient();
# Add default server (localhost).
$gmclient->addServer();
echo 'Sending job'.PHP_EOL;
# Send reverse job
do
{
$result = $gmclient->doNormal('reverse', 'Hello!');
# Check for various return packets and errors.
switch($gmclient->returnCode())
{
case GEARMAN_WORK_DATA:
echo 'Data: '.$result . PHP_EOL;;
break;
case GEARMAN_WORK_STATUS:
list($numerator, $denominator)= $gmclient->doStatus();
echo 'Status: '.$numerator.'/'.$denominator.' complete'. PHP_EOL;
break;
case GEARMAN_WORK_FAIL:
echo 'Failed\n';
exit;
case GEARMAN_SUCCESS:
echo 'Success: $result\n';
break;
default:
echo 'RET: ' . $gmclient->returnCode() . PHP_EOL;
exit;
}
}
while($gmclient->returnCode() != GEARMAN_SUCCESS);
?>
See also Gearman on PHP and Gearman
ext/com
[Since 0.8.4] - [ -P Extensions/Extcom ] - [ Online docs ]
Extension COM and .Net (Windows).
COM is an acronym for 'Component Object Model'; it is an object orientated layer (and associated services) on top of DCE RPC (an open standard) and defines a common calling convention that enables code written in any language to call and interoperate with code written in any other language (provided those languages are COM aware).
<?php
$domainObject = new COM(WinNT://Domain);
foreach ($domainObject as $obj) {
echo $obj->Name . <br />;
}
?>
See also and COM and .Net (Windows)
ext/gmagick
[Since 0.8.4] - [ -P Extensions/Extgmagick ] - [ Online docs ]
Extension gmagick.
Gmagick is a php extension to create, modify and obtain meta information of images using the GraphicsMagick API.
<?php
//Instantiate a new Gmagick object
$image = new Gmagick('example.jpg');
//Make thumbnail from image loaded. 0 for either axes preserves aspect ratio
$image->thumbnailImage(100, 0);
//Create a border around the image, then simulate how the image will look like as an oil painting
//Note the chaining of mutator methods which is supported in gmagick
$image->borderImage(yellow, 8, 8)->oilPaintImage(0.3);
//Write the current image at the current state to a file
$image->write('example_thumbnail.jpg');
?>
See also PHP gmagick and gmagick
ext/ibase
[Since 0.8.4] - [ -P Extensions/Extibase ] - [ Online docs ]
Extensions Interbase and Firebird .
Firebird is a relational database offering many ISO SQL-2003 features that runs on Linux, Windows, and a variety of Unix platforms.
<?php
$host = 'localhost:/path/to/your.gdb';
$dbh = ibase_connect($host, $username, $password);
$stmt = 'SELECT * FROM tblname';
$sth = ibase_query($dbh, $stmt) or die(ibase_errmsg());
?>
See also Firebase / Interbase and Firebird
ext/inotify
[Since 0.8.4] - [ -P Extensions/Extinotify ] - [ Online docs ]
Extension inotify.
The Inotify extension gives access to the Linux kernel subsystem that acts to extend filesystems to notice changes to the filesystem, and report those changes to applications.
<?php
// Open an inotify instance
$fd = inotify_init();
// Watch __FILE__ for metadata changes (e.g. mtime)
$watch_descriptor = inotify_add_watch($fd, __FILE__, IN_ATTRIB);
// generate an event
touch(__FILE__);
// Read events
$events = inotify_read($fd);
print_r($events);
// The following methods allows to use inotify functions without blocking on inotify_read():
// - Using `stream_select() <https://www.php.net/stream_select>`_ on $fd:
$read = array($fd);
$write = null;
$except = null;
stream_select($read,$write,$except,0);
// - Using `stream_set_blocking() <https://www.php.net/stream_set_blocking>`_ on $fd
stream_set_blocking($fd, 0);
inotify_read($fd); // Does no block, and return false if no events are pending
// - Using inotify_queue_len() to check if event queue is not empty
$queue_len = inotify_queue_len($fd); // If > 0, inotify_read() will not block
// Stop watching __FILE__ for metadata changes
inotify_rm_watch($fd, $watch_descriptor);
// Close the inotify instance
// This may have closed all watches if this was not already done
fclose($fd);
?>
See also ext/inotify manual and inotify
ext/xdiff
[Since 0.8.4] - [ -P Extensions/Extxdiff ] - [ Online docs ]
Extension xdiff.
xdiff extension enables you to create and apply patch files containing differences between different revisions of files.
<?php
$old_version = 'my_script-1.0.php';
$patch = 'my_script.patch';
$errors = xdiff_file_patch($old_version, $patch, 'my_script-1.1.php');
if (is_string($errors)) {
echo 'Rejects:'.PHP_EOL;
echo $errors;
}
?>
See also and libxdiff
ext/ev
[Since 0.8.4] - [ -P Extensions/Extev ] - [ Online docs ]
Extension ev.
ext/ev is a high performance full-featured event loop written in C.
<?php
// Create and start timer firing after 2 seconds
$w1 = new EvTimer(2, 0, function () {
echo '2 seconds elapsed'.PHP_EOL;
});
// Create and launch timer firing after 2 seconds repeating each second
// until we manually stop it
$w2 = new EvTimer(2, 1, function ($w) {
echo 'is called every second, is launched after 2 seconds'.PHP_EOL;
echo 'iteration = ', Ev::iteration(), PHP_EOL;
// Stop the watcher after 5 iterations
Ev::iteration() == 5 and $w->stop();
// Stop the watcher if further calls cause more than 10 iterations
Ev::iteration() >= 10 and $w->stop();
});
// Create stopped timer. It will be inactive until we start it ourselves
$w_stopped = EvTimer::createStopped(10, 5, function($w) {
echo 'Callback of a timer created as stopped'.PHP_EOL;
// Stop the watcher after 2 iterations
Ev::iteration() >= 2 and $w->stop();
});
// Loop until Ev::stop() is called or all of watchers stop
Ev::run();
// Start and look if it works
$w_stopped->start();
echo 'Run single iteration'.PHP_EOL;
Ev::run(Ev::RUN_ONCE);
echo 'Restart the second watcher and try to handle the same events, but don\'t block'.PHP_EOL;
$w2->again();
Ev::run(Ev::RUN_NOWAIT);
$w = new EvTimer(10, 0, function() {});
echo 'Running a blocking loop'.PHP_EOL;
Ev::run();
echo 'END'.PHP_EOL;
?>
See also Ev and libev
ext/php-ast
[Since 0.8.4] - [ -P Extensions/Extast ] - [ Online docs ]
PHP-AST extension (PHP 7.0 +).
<?php
$code = <<<'EOC'
<?php
$var = 42;
EOC;
var_dump(ast\parse_code($code, $version=50));
?>
See also ext/ast, Extension exposing PHP 7 abstract syntax tree and Introduction of PHP parse and its application in hyperf
ext/xml
[Since 0.8.4] - [ -P Extensions/Extxml ] - [ Online docs ]
Extension xml (Parser).
This PHP extension implements support for James Clark's expat in PHP. This toolkit lets you parse, but not validate, XML documents.
<?php
$file = data.xml;
$depth = array();
function startElement($parser, $name, $attrs)
{
global $depth;
if (!isset($depth[$parser])) {
$depth[$parser] = 0;
}
for ($i = 0; $i < $depth[$parser]; $i++) {
echo ;
}
echo $name\n;
$depth[$parser]++;
}
function endElement($parser, $name)
{
global $depth;
$depth[$parser]--;
}
$xml_parser = xml_parser_create();
xml_set_element_handler($xml_parser, startElement, endElement);
if (!($fp = fopen($file, r))) {
die(could not open XML input);
}
while ($data = fread($fp, 4096)) {
if (!xml_parse($xml_parser, $data, feof($fp))) {
die(sprintf(XML error: %s at line %d,
xml_error_string(xml_get_error_code($xml_parser)),
xml_get_current_line_number($xml_parser)));
}
}
xml_parser_free($xml_parser);
?>
See also and XML Parser
ext/xhprof
[Since 0.8.4] - [ -P Extensions/Extxhprof ] - [ Online docs ]
Extension xhprof.
XHProf is a light-weight hierarchical and instrumentation based profiler.
<?php
xhprof_enable(XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY);
for ($i = 0; $i <= 1000; $i++) {
$a = $i * $i;
}
$xhprof_data = xhprof_disable();
$XHPROF_ROOT = '/tools/xhprof/';
include_once $XHPROF_ROOT . '/xhprof_lib/utils/xhprof_lib.php';
include_once $XHPROF_ROOT . '/xhprof_lib/utils/xhprof_runs.php';
$xhprof_runs = new XHProfRuns_Default();
$run_id = $xhprof_runs->save_run($xhprof_data, 'xhprof_testing');
echo 'http://localhost/xhprof/xhprof_html/index.php?run={$run_id}&source=xhprof_testing'.PHP_EOL;
?>
See also XHprof Documentation and ext/apcu
Indices Are Int Or String
[Since 0.8.4] - [ -P Structures/IndicesAreIntOrString ] - [ Online docs ]
Indices in an array notation such as $array['indice'] may only be integers or string.
Boolean, Null or float will be converted to their integer or string equivalent.
<?php
$a = [true => 1,
1.0 => 2,
1.2 => 3,
1 => 4,
'1' => 5,
0.8 => 6,
0x1 => 7,
01 => 8,
null => 1,
'' => 2,
false => 1,
0 => 2,
'0.8' => 3,
'01' => 4,
'2a' => 5
];
print_r($a);
/*
The above displays
Array
(
[1] => 8
[0] => 2
[] => 2
[0.8] => 3
[01] => 4
[2a] => 5
)
*/
?>
Decimal numbers are rounded to the closest integer; Null is transtyped to '' (empty string); true is 1 and false is 0; Integers in strings are transtyped, while partial numbers or decimals are not analyzed in strings.
As a general rule of thumb, only use integers or strings that don\'t look like integers.
This analyzer may find constant definitions, when available.
Note also that PHP detects integer inside strings, and silently turn them into integers. Partial and octal numbers are not transformed.
<?php
$a = [1 => 1,
'2' => 2,
'011' => 9, // octal number
'11d' => 11, // partial number
];
var_dump($a);
/*
The above displays
array(4) {
[1]=>
int(1)
[2]=>
int(2)
[011]=>
int(9)
[11d]=>
int(11)
}*/
?>
See also and Arrays syntax
Should Typecast
[Since 0.8.4] - [ -P Type/ShouldTypecast ] - [ Online docs ]
When typecasting, it is better to use the casting operator, such as (int) or (bool) .
Functions such as intval() or settype() are always slower.
<?php
// Fast version
$int = (int) $X;
// Slow version
$int = intval($X);
// Convert to base 8 : can't use (int) for that
$int = intval($X, 8);
?>
This is a micro-optimisation, although such conversion may be use multiple times, leading to a larger performance increase.
Note that intval() may also be used to convert an integer to another base. Intval() called with 2 arguments are skipped by this rule.
No Self Referencing Constant
[Since 0.8.4] - [ -P Classes/NoSelfReferencingConstant ] - [ Online docs ]
It is not possible to use a constant to define itself in a class. It yields a fatal error at runtime.
The PHP error reads : Cannot declare self-referencing constant 'self::C2' . Unlike PHP which is self-referencing, self referencing variables can't have a value : just don't use that.
<?php
class a {
const C1 = 1; // fully defined constant
const C2 = self::C2; // self referencing constant
const C3 = a::C3 + 2; // self referencing constant
}
?>
The code may access an already declared constant with self or with its class name.
<?php
class a {
const C1 = 1;
const C2 = a::C1;
}
?>
This error is not detected by linting. It is only detected at instantiation time : if the class is not used, it won't appear.
No Direct Usage
[Since 0.8.4] - [ -P Structures/NoDirectUsage ] - [ Online docs ]
The results of the following functions shouldn't be used directly, but checked first.
For example, glob() returns an array, unless some error happens, in which case it returns a boolean (false). In such case, however rare it is, plugging glob() directly in a foreach() loops will yield errors.
<?php
// Used without check :
foreach(glob('.') as $file) { /* do Something */ }.
// Used without check :
$files = glob('.');
if (!is_array($files)) {
foreach($files as $file) { /* do Something */ }.
}
?>
Break Outside Loop
[Since 0.8.4] - [ -P Structures/BreakOutsideLoop ] - [ Online docs ]
Starting with PHP 7, break or continue that are outside a loop (for, foreach(), do...while(), while()) or a switch() statement won't compile anymore.
It is not possible anymore to include a piece of code inside a loop that will then break.
<?php
// outside a loop : This won't compile
break 1;
foreach($array as $a) {
break 1; // Compile OK
break 2; // This won't compile, as this break is in one loop, and not 2
}
foreach($array as $a) {
foreach($array2 as $a2) {
break 2; // OK in PHP 5 and 7
}
}
?>
Else Usage
[Since 0.8.4] - [ -P Structures/ElseUsage ] - [ Online docs ]
Else can be avoided by various means.
For example, defaulting values before using a condition; returning early in the method, thus skipping long else blocks; using a ternary operator to assign values conditionnaly.
Else is the equivalent of the default clause in a switch statement. When the if/then structure can be replaced with a switch can (albeit, a 2-case switch seems strange), then else usage is a good solution.
<?php
// $a is always set
$a = 'default';
if ($condition) {
$a = foo($condition);
}
// Don't use else for default : set default before
if ($condition) {
$a = foo($condition);
} else {
$a = 'default';
}
// Use then to exit
if ( ! $condition) {
return;
}
$a = foo($condition);
// don't use else to return
if ($condition) {
$a = foo($condition);
} else {
return;
}
?>
See also Avoid Else, Return Early and Why does clean code forbid else expression
Avoid Substr() One
[Since 0.8.4] - [ -P Structures/NoSubstrOne ] - [ Online docs ]
Use array notation $string[$position] to reach a single byte in a string.
There are two ways to access a byte in a string : substr() and $v[$pos] .
The second style is more readable. It may be up to four times faster, though it is a micro-optimization. It is recommended to use it.
PHP 7.1 also introduces the support of negative offsets as string index : negative offset are also reported.
<?php
$string = 'ab人cde';
echo substr($string, $pos, 1);
echo $string[$pos];
echo mb_substr($string, $pos, 1);
// when $pos = 1
// displays bbb
// when $pos = 2
// displays ??人
?>
Beware that substr() and $v[$pos] are similar, while mb_substr() is not. The first function works on bytes, while the latter works on characters.
Anonymous Classes
[Since 0.8.4] - [ -P Classes/Anonymous ] - [ Online docs ]
Anonymous classes.
<?php
// Anonymous class, available since PHP 7.0
$object = new class { function __construct() { echo __METHOD__; } };
?>
See also and Anonymous classes
Coalesce
[Since 0.8.4] - [ -P Php/Coalesce ] - [ Online docs ]
Usage of coalesce operator.
Note that the coalesce operator is a special case of the ternary operator.
<?php
// Coalesce operator, since PHP 5.3
$a = $b ?: 'default value';
// Equivalent to $a = $b ? $b : 'default value';
?>
See also and Ternary Operator
Double Assignation
[Since 0.8.4] - [ -P Structures/DoubleAssignation ] - [ Online docs ]
This happens when a container (variable, property, array index) is assigned with values twice in a row. One of them is probably a debug instruction, that was forgotten.
<?php
// Normal assignation
$a = 1;
// Double assignation
$b = 2;
$b = 3;
?>
Empty List
[Since 0.8.4] - [ -P Php/EmptyList ] - [ Online docs ]
Empty list() are not allowed anymore in PHP 7. There must be at least one variable in the list call.
<?php
//Not accepted since PHP 7.0
list() = array(1,2,3);
//Still valid PHP code
list(,$x) = array(1,2,3);
?>
Directives Usage
[Since 0.8.4] - [ -P Php/DirectivesUsage ] - [ Online docs ]
List of the directives mentioned in the code.
<?php
//accessing the configuration to change it
ini_set('timelimit', -1);
//accessing the configuration to check it
ini_get('safe_mode');
?>
See also and `ini_set()
Useless Brackets
[Since 0.8.4] - [ -P Structures/UselessBrackets ] - [ Online docs ]
Standalone brackets have no use. Brackets are used to delimit a block of code, and are used by control statements. They may also be used to protect variables in strings.
Standalone brackets may be a left over of an old instruction, or a misunderstanding of the alternative syntax.
<?php
// The following brackets are useless : they are a leftover from an older instruction
// if (DEBUG)
{
$a = 1;
}
// Here, the extra brackets are useless
for($a = 2; $a < 5; $a++) : {
$b++;
} endfor;
?>
preg_replace With Option e
[Since 0.8.4] - [ -P Structures/pregOptionE ] - [ Online docs ]
preg_replace() supported the /e option until PHP 7.0. It allowed the use of eval()'ed expression as replacement. This has been dropped in PHP 7.0, for security reasons.
preg_replace() with /e option may be replaced with preg_replace_callback() and a closure, or preg_replace_callback_array() and an array of closures.
<?php
// preg_replace with /e
$string = 'abcde';
// PHP 5.6 and older usage of /e
$replaced = preg_replace('/c/e', 'strtoupper($0)', $string);
// PHP 7.0 and more recent
// With one replacement
$replaced = preg_replace_callback('/c/', function ($x) { return strtoupper($x[0]); }, $string);
// With several replacements, preventing multiple calls to preg_replace_callback
$replaced = preg_replace_callback_array(array('/c/' => function ($x) { return strtoupper($x[0]); },
'/[a-b]/' => function ($x) { return strtolower($x[0]); }), $string);
?>
eval() Without Try
[Since 0.8.4] - [ -P Structures/EvalWithoutTry ] - [ Online docs ]
eval()
<?php
$code = 'This is no PHP code.';
//PHP 5 style
eval($code);
// Ends up with a Fatal error, at execution time
//PHP 7 style
try {
eval($code);
} catch (ParseError $e) {
cleanUpAfterEval();
}
?>
Note that it will catch situations where eval()
Global In Global
[Since 0.8.4] - [ -P Structures/GlobalInGlobal ] - [ Online docs ]
List of global variables. There are the global variables, defined with the global keyword, and the implicit global variables, defined in the global scope.
<?php
global $explicitGlobal; // in global namespace
$implicitGlobal = 1; // in global namespace, variables are automatically global
function foo() {
global $explicitGlobalInFoo; // in functions, globals must be declared with global
}
?>
See also and Variable Scope
ext/fann
[Since 0.8.4] - [ -P Extensions/Extfann ] - [ Online docs ]
Extension FANN : Fast Artificial Neural Network.
PHP binding for FANN library which implements multi-layer artificial neural networks with support for both fully connected and sparsely connected networks.
<?php
$num_input = 2;
$num_output = 1;
$num_layers = 3;
$num_neurons_hidden = 3;
$desired_error = 0.001;
$max_epochs = 500000;
$epochs_between_reports = 1000;
$ann = fann_create_standard($num_layers, $num_input, $num_neurons_hidden, $num_output);
if ($ann) {
fann_set_activation_function_hidden($ann, FANN_SIGMOID_SYMMETRIC);
fann_set_activation_function_output($ann, FANN_SIGMOID_SYMMETRIC);
$filename = dirname(__FILE__) . '/xor.data';
if (fann_train_on_file($ann, $filename, $max_epochs, $epochs_between_reports, $desired_error))
fann_save($ann, dirname(__FILE__) . '/xor_float.net');
fann_destroy($ann);
}
?>
See also extension FANN, PHP-ML, Rubix ML and lib FANN
Relay Function
[Since 0.8.4] - [ -P Functions/RelayFunction ] - [ Online docs ]
Relay function only delegates workload to another one.
Relay functions and methods are delegating the actual work to another function or method. They do not have any impact on the results, besides exposing another name for the same feature.
<?php
function myStrtolower($string) {
return \strtolower($string);
}
?>
Relay functions are typical of transition API, where an old API have to be preserved until it is fully migrated. Then, they may be removed, so as to reduce confusion, and simplify the API.
func_get_arg() Modified
[Since 0.8.4] - [ -P Functions/funcGetArgModified ] - [ Online docs ]
func_get_arg() and func_get_args() used to report the calling value of the argument until PHP 7.
Since PHP 7, it is reporting the value of the argument at calling time, which may have been modified by a previous instruction.
<?php
function x($a) {
$a++;
print func_get_arg(0);
}
x(0);
?>
This code will display 1 in PHP 7, and 0 in PHP 5.
Use Web
[Since 0.8.4] - [ -P Php/UseWeb ] - [ Online docs ]
The code is used in web environment.
The web usage is identified through the usage of the superglobals.
<?php
// Accessing $_GET is possible when PHP is used in a web server.
$x = filter_validate($_GET['x'], FILTER_EMAIL);
?>
Use Cli
[Since 0.8.4] - [ -P Php/UseCli ] - [ Online docs ]
Signal the usage of code in CLI mode, through the usage of $argv and $argc variables, or the getopt() function.
<?php
// Characteristics of CLI usage
getopt(abcd);
?>
Avoid get_class()
[Since 0.8.4] - [ -P Structures/UseInstanceof ] - [ Online docs ]
get_class() should be replaced with the instanceof operator to check the class of an object.
get_class() only compares the full namespace name of the object's class, while instanceof actually resolves the name, using the local namespace and aliases.
<?php
use Stdclass as baseClass;
function foo($arg) {
// Slow and prone to namespace errors
if (get_class($arg) === 'Stdclass') {
// doSomething()
}
}
function bar($arg) {
// Faster, and uses aliases.
if ($arg instanceof baseClass) {
// doSomething()
}
}
?>
See also get_class and Instanceof
Silently Cast Integer
[Since 0.8.4] - [ -P Type/SilentlyCastInteger ] - [ Online docs ]
Those are integer literals that are cast to a float when running PHP. They are too big for the current PHP version, and PHP resorts to cast them into a float, which has a much larger capacity but a lower precision.
Compare your literals to PHP_MAX_INT (typically 9223372036854775807 ) and PHP_MIN_INT (typically -9223372036854775808 ).
This applies to binary ( 0b10101 ...), octal ( 0123123 ...) and hexadecimal ( 0xfffff ...) too.
<?php
echo 0b1010101101010110101011010101011010101011010101011010101011010111;
//6173123008118052203
echo 0b10101011010101101010110101010110101010110101010110101010110101111;
//1.2346246016236E+19
echo 0123123123123123123123;
//1498121094048818771
echo 01231231231231231231231;
//1.1984968752391E+19
echo 0x12309812311230;
//5119979279159856
echo 0x12309812311230fed;
//2.0971435127439E+19
echo 9223372036854775807; //PHP_MAX_INT
//9223372036854775807
echo 9223372036854775808;
9.2233720368548E+18?>
See also and Integer overflow
Error Messages
[Since 0.8.4] - [ -P Structures/ErrorMessages ] - [ Online docs ]
Error message when an error is reported in the code. Those messages will be read by whoever is triggering the error, and it has to be helpful.
It is a good exercise to read the messages out of context, and try to understand what is about.
<?php
// Not so helpful messages
die('Here be monsters');
exit('An error happened');
throw new Exception('Exception thrown at runtime');
?>
Error messages are spotted via die, exit, trigger_error() or throw.
Timestamp Difference
[Since 0.8.4] - [ -P Structures/TimestampDifference ] - [ Online docs ]
Avoid adding or subtracting quantities of seconds to measure time.
time() , microtime()
Those functions are subject to variations, depending on system clock variations, such as daylight saving time difference (every spring and fall, one hour variation), or leap seconds, happening on June, 30th or December 31th , as announced by IERS.
<?php
// Calculating tomorow, same hour, the wrong way
// tomorrow is not always in 86400s, especially in countries with daylight saving
$tomorrow = time() + 86400;
// Good way to calculate tomorrow
$datetime = new DateTime('tomorrow');
?>
When the difference may be rounded to a larger time unit (rounding the difference to days, or several hours), the variation may be ignored safely.
When the difference is very small, it requires a better way to measure time difference, such as `Ticks
`ext/hrtime
See also PHP DateTime difference – it’s a trap! and PHP Daylight savings bug?
Php7 Relaxed Keyword
[Since 0.8.4] - [ -P Php/Php7RelaxedKeyword ] - [ Online docs ]
Most of the traditional PHP keywords may be used inside classes, trait or interfaces.
<?php
// Compatible with PHP 7.0 +
class foo {
// as is a PHP 5 keyword
public function as() {
}
}
?>
This was not the case in PHP 5, and will yield parse errors.
See also and Loosening Reserved Word Restrictions
ext/pecl_http
[Since 0.8.4] - [ -P Extensions/Exthttp ] - [ Online docs ]
Extension HTTP.
This HTTP extension aims to provide a convenient and powerful set of functionalities for one of PHP major applications.
It eases handling of HTTP URL, headers and messages, provides means for negotiation of a client's preferred content type, language and charset, as well as a convenient way to send any arbitrary data with caching and resuming capabilities.
It provides powerful request functionality with support for parallel requests.
<?php
$client = new http\Client;
$client->setSslOptions(array("verifypeer" => true));
$client->addSslOptions(array("verifyhost" => 2));
$client->enqueue($req = new http\Client\Request("GET", "https://twitter.com/"));
$client->s`end() <https://www.php.net/end>`_;
$ti = (array) $client->getTransferInfo($req);
var_dump($ti);
?>
See also ext-http and pecl_http
Unused Parameter
[Since 0.8.4] - [ -P Functions/UnusedArguments ] - [ Online docs ]
Those parameters are not used in the method or function.
Unused parameters should be removed in functions : they are dead code.
Unused parameters also should be removed from methods, though there may have external reasons for them to stay. In particular, they might be defined in a parent class, or an interface, and cannot be removed.
<?php
// $unused is in the signature, but not used.
function foo($unused, $b, $c) {
return $b + $c;
}
interface i {
function goo($a);
}
class a implements i {
// goo signature comes from the interface
function goo($a) {
return 3;
}
}
?>
Uses Environment
[Since 0.8.4] - [ -P Php/UsesEnv ] - [ Online docs ]
Spot usage of $_ENV and getenv() putenv() functions that will fetch data from the environment.
<?php
// Take some configuration from the environment
$secret_key = getenv('secret_key');
?>
Switch To Switch
[Since 0.8.4] - [ -P Structures/SwitchToSwitch ] - [ Online docs ]
The following structures are based on if / elseif / else. Since they have more than three conditions (not withstanding the final else), it is recommended to use the switch structure, so as to make this more readable.
On the other hand, switch() structures with less than 3 elements should be expressed as a if / else structure.
Note that if condition that uses strict typing (=== or !==) can't be converted to switch() as the latter only performs == or != comparisons.
<?php
if ($a == 1) {
} elseif ($a == 2) {
} elseif ($a == 3) {
} elseif ($a == 4) {
} else {
}
// Better way to write long if/else lists
switch ($a) {
case 1 :
doSomething(1);
break 1;
case 2 :
doSomething(2);
break 1;
case 3 :
doSomething(3);
break 1;
case 4 :
doSomething(4);
break 1;
default :
doSomething();
break 1;
}
?>
Note that simple switch statement, which compare a variable to a literal are optimised in PHP 7.2 and more recent. This gives a nice performance boost, and keep code readable.
See also PHP 7.2's switch optimisations and Is Your Code Readable By Humans? Cognitive Complexity Tells You
Wrong Parameter Type
[Since 0.8.4] - [ -P Php/InternalParameterType ] - [ Online docs ]
The expected parameter is not of the correct type. Check PHP documentation to know which is the right format to be used.
<?php
// `substr() <https://www.php.net/substr>`_ shouldn't work on integers.
// the first argument is first converted to string, and it is 123456.
echo substr(123456, 0, 4); // display 1234
// `substr() <https://www.php.net/substr>`_ shouldn't work on boolean
// the first argument is first converted to string, and it is 1, and not t
echo substr(true, 0, 1); // displays 1
// `substr() <https://www.php.net/substr>`_ works correctly on strings.
echo substr(123456, 0, 4);
?>
Redefined Methods
[Since 0.8.4] - [ -P Classes/RedefinedMethods ] - [ Online docs ]
Redefined methods are overwritten methods. Those methods are defined in different classes that are part of the same classes hierarchy.
Protected and public redefined methods replace each other. Private methods are kept separated, and depends on the caller to be distinguished.
<?php
class foo {
function method() {
return 1;
}
}
class bar extends foo {
function method() {
return 2;
}
}
?>
See also and Object Inheritance
Wrong fopen() Mode
[Since 0.8.4] - [ -P Php/FopenMode ] - [ Online docs ]
Wrong file opening for fopen().
fopen() has a few modes, as described in the documentation : 'r', 'r+', for reading; 'w', 'w+' for writing; 'a', 'a+' for appending; 'x', 'x+' for modifying; 'c', 'c+' for writing and locking, 't' for text files and windows only.
An optional 'b' may be used to make the fopen() call more portable and binary safe. Another optional 't' may be used to make the fopen() call process automatically text input : this one should be avoided.
<?php
// open the file for reading, in binary mode
$fp = fopen('/tmp/php.txt', 'rb');
// New option e in PHP 7.0.16 and 7.1.2 (beware of compatibility)
$fp = fopen('/tmp/php.txt', 'rbe');
// Unknown option x
$fp = fopen('/tmp/php.txt', 'rbx');
?>
Any other values are not understood by PHP.
Is CLI Script
[Since 0.8.4] - [ -P Files/IsCliScript ] - [ Online docs ]
Mark a file as a CLI script, based on the usage of #!.
PHP Bugfixes
[Since 0.8.4] - [ -P Php/MiddleVersion ] - [ Online docs ]
This is the list of features, used in the code, that also received a bug fix in recent PHP versions.
Negative Power
[Since 0.8.4] - [ -P Structures/NegativePow ] - [ Online docs ]
The power operator ** has higher precedence than the sign operators + and -.
This means that -2 ** 2 == -4. It is in fact, -(2 ** 2).
When using negative power, it is clearer to add parenthesis or to use the pow() function, which has no such ambiguity :
<?php
// -2 to the power of 2 (a square)
pow(-2, 2) == 4;
// minus 2 to the power of 2 (a negative square)
-2 ** 2 == -(2 ** 2) == 4;
?>
Already Parents Interface
[Since 0.8.4] - [ -P Interfaces/AlreadyParentsInterface ] - [ Online docs ]
The same interface is implemented by a class and one of its children.
That way, the child doesn't need to implement the interface, nor define its methods to be an instance of the interface.
<?php
interface i {
function i();
}
class A implements i {
function i() {
return __METHOD__;
}
}
// This implements is useless.
class AB extends A implements i {
// No definition for function i()
}
// Implements i is understated
class AB extends A {
// redefinition of the i method
function i() {
return __METHOD__.' ';
}
}
$x = new AB;
var_dump($x instanceof i);
// true
$x = new AC;
var_dump($x instanceof i);
// true
?>
This analysis may report classes which do not explicitly implements any interfaces : the issue is then coming from the parents.
Use random_int()
[Since 0.8.4] - [ -P Php/BetterRand ] - [ Online docs ]
rand() and mt_rand() should be replaced with random_int().
At worse, rand() should be replaced with mt_rand(), which is a drop-in replacement and srand() by mt_srand().
random_int() replaces rand(), and has no seeding function like srand().
Other sources of entropy that should be replaced by random_int() : microtime(), uniqid(), time(). Those a often combined with hashing functions and mixed with other sources of entropy, such as a salt.
<?php
// Avoid using this
$random = rand(0, 10);
// Drop-in replacement
$random = mt_rand(0, 10);
// Even better but different :
// valid with PHP 7.0+
try {
$random = random_int(0, 10);
} catch (\Exception $e) {
// process case of not enoug random values
}
// This is also a source of entropy, based on `srand() <https://www.php.net/srand>`_
// random_int() is a drop-in replacement here
$a = sha256(`uniqid() <https://www.php.net/uniqid>`_);
?>
Since PHP 7, random_int() along with random_bytes(), provides cryptographically secure pseudo-random bytes, which are good to be used
when security is involved. openssl_random_pseudo_bytes() may be used when the OpenSSL extension is available.
See also CSPRNG and OpenSSL
Can't Extend Final
[Since 0.8.4] - [ -P Classes/CantExtendFinal ] - [ Online docs ]
It is not possible to extend final classes.
Since PHP fails with a fatal error, this means that the extending class is probably not used in the rest of the code. Check for dead code.
<?php
// File Foo
final class foo {
public final function bar() {
// doSomething
}
}
?>
In a separate file :
<?php
// File Bar
class bar extends foo {
}
?>
See also and Final Keyword
Ternary In Concat
[Since 0.8.4] - [ -P Structures/TernaryInConcat ] - [ Online docs ]
Ternary and coalesce operator have higher priority than dot '.' for concatenation. This means that :
<?php
// print B0CE as expected
print 'B'.$b.'C'. ($b > 1 ? 'D') : 'E';
// print E, instead of B0CE
print 'B'.$b.'C'. $b > 1 ? 'D' : 'E';
print 'B'.$b.'C'. $b > 1 ? 'D' : 'E';
?>
prints actually 'E' , instead of the awaited 'B0CE' .
To be safe, always add parenthesis when using ternary operator with concatenation.
See also and Operator Precedence
Using $this Outside A Class
[Since 0.8.4] - [ -P Classes/UsingThisOutsideAClass ] - [ Online docs ]
$this is a special variable, that should only be used in a class context.
Until PHP 7.1, $this may be used as an argument in a function or a method, a global, a static : while this is legit, it sounds confusing enough to avoid it.
<?php
function foo($this) {
echo $this;
}
// A closure can be bound to an object at later time. It is valid usage.
$closure = function ($x) {
echo $this->foo($x);
}
?>
Starting with PHP 7.1, the PHP engine check thoroughly that $this is used in an appropriate manner, and raise fatal errors in case it isn't.
Yet, it is possible to find $this outside a class : if the file is included inside a class, then $this will be recognized and validated. If the file is included outside a class context, it will yield a fatal error : Using $this when not in object context .
See also Closure::bind and The Basics
ext/tokyotyrant
[Since 0.8.4] - [ -P Extensions/Exttokyotyrant ] - [ Online docs ]
Extension for Tokyo Tyrant.
tokyo_tyrant extension provides a wrapper for Tokyo Tyrant client libraries.
<?php
$tt = new TokyoTyrant("localhost");
$tt->put("key", "value");
echo $tt->get("key");
?>
See also tokyo_tyrant and Tokyo cabinet
ext/v8js
[Since 0.8.4] - [ -P Extensions/Extv8js ] - [ Online docs ]
Extension v8js.
This extension embeds the V8 Javascript Engine into PHP.
<?php
$v8 = new V8Js();
/* basic.js */
$JS = <<< EOT
len = print('Hello' + ' ' + 'World!' + '\n');
len;
EOT;
try {
var_dump($v8->executeString($JS, 'basic.js'));
} catch (V8JsException $e) {
var_dump($e);
}
?>
See also V8 Javascript Engine Integration, V8 Javascript Engine for PHP and pecl v8js
Yield Usage
[Since 0.8.4] - [ -P Php/YieldUsage ] - [ Online docs ]
Usage of generators, with yield keyword.
Yield was introduced in PHP 5.5, and is backward incompatible.
<?php
function prime() {
$primes = [2, 3, 5, 7, 11, 13, 17, 19];
foreach($primes as $prime) {
yield $prime;
}
}
?>
See also Generator Syntax, Deal with Memory Gently using "Yield" in PHP and Understanding PHP Generators
Yield From Usage
[Since 0.8.4] - [ -P Php/YieldFromUsage ] - [ Online docs ]
Usage of generator delegation, with yield from keyword.
In PHP 7, generator delegation allows you to yield values from another Generator , Traversable object, or array by using the yield from .
Yield from was introduced in PHP 7.1, and is backward incompatible.
<?php
// Yield delegation
function foo() {
yield from bar();
}
function bar() {
yield 1;
}
?>
See also Generator Syntax and Understanding PHP Generators
Pear Usage
[Since 0.8.4] - [ -P Php/PearUsage ] - [ Online docs ]
Pear Usage : list of Pear packages in use.
<?php
require_once('MDB2.php');
$dsn = 'mysql://user:pass@host';
$mdb2 = &MDB2::factory($dsn);
$mdb2->setFetchMode(MDB2_FETCHMODE_ASSOC);
?>
See also and PEAR
Undefined Trait
[Since 0.8.4] - [ -P Traits/UndefinedTrait ] - [ Online docs ]
Those are undefined, traits .
When the using class or trait is instantiated, PHP emits a a fatal error.
<?php
use Composer/Component/someTrait as externalTrait;
trait t {
function foo() {}
}
// This class uses trait that are all known
class hasOnlyDefinedTrait {
use t, externalTrait;
}
// This class uses trait that are unknown
class hasUndefinedTrait {
use unknownTrait, t, externalTrait;
}
?>
Trait which are referenced in a `use` expression are omitted: they are considered part of code that is probably outside the current code, either omitted or in external component.
No Hardcoded Hash
[Since 0.8.4] - [ -P Structures/NoHardcodedHash ] - [ Online docs ]
Hash should never be hardcoded.
Hashes may be MD5, SHA1, SHA512, Bcrypt or any other. Such values must be easily changed, for security reasons, and the source code is not the safest place to hide it.
<?php
// Those strings may be sha512 hashes.
// it is recomemdned to check if they are static or should be put into configuration
$init512 = array( // initial values for SHA512
'6a09e667f3bcc908', 'bb67ae8584caa73b', '3c6ef372fe94f82b', 'a54ff53a5f1d36f1',
);
// strings which are obvious conversion are ignored
$decimal = intval('87878877', 12);
?>
See also Salted Password Hashing - Doing it Right and Hash-Buster
Identical Conditions
[Since 0.8.4] - [ -P Structures/IdenticalConditions ] - [ Online docs ]
These logical expressions contain members that are identical.
This means those expressions may be simplified.
<?php
// twice $a
if ($a || $b || $c || $a) { }
// Hiding in parenthesis is bad
if (($a) ^ ($a)) {}
// expressions may be large
if ($a === 1 && 1 === $a) {}
?>
Unkown Regex Options
[Since 0.8.4] - [ -P Structures/UnknownPregOption ] - [ Online docs ]
Regex support in PHP accepts the following list of options : eimsuxADJSUX .
All other letter used as option are not supported : depending on the situation, they may be ignored or raise an error.
<?php
// all options are available
if (preg_match('/\d+/isA', $string, $results)) { }
// p and h are not regex options, p is double
if (preg_match('/\d+/php', $string, $results)) { }
?>
See also and Pattern Modifiers
No Choice
[Since 0.8.4] - [ -P Structures/NoChoice ] - [ Online docs ]
A conditional structure is being used, but both alternatives are the same, leading to the illusion of choice.
Either the condition is useless, and may be removed, or the alternatives need to be distinguished.
<?php
if ($condition == 2) {
doSomething();
} else {
doSomething();
}
$condition == 2 ? doSomething() : doSomething();
?>
Common Alternatives
[Since 0.8.4] - [ -P Structures/CommonAlternatives ] - [ Online docs ]
In the following conditional structures, expressions were found that are common to both 'then' and 'else'. It may be interesting, though not always possible, to put them both out of the conditional, and reduce line count.
<?php
if ($c == 5) {
$b = strtolower($b[2]);
$a++;
} else {
$b = strtolower($b[2]);
$b++;
}
?>
may be rewritten in :
<?php
$b = strtolower($b[2]);
if ($c == 5) {
$a++;
} else {
$b++;
}
?>
Logical Mistakes
[Since 0.8.4] - [ -P Structures/LogicalMistakes ] - [ Online docs ]
Avoid logical mistakes within long expressions.
Sometimes, the logic is not what it seems. It is important to check the actual impact of every part of the logical expression. Do not hesitate to make a table with all possible cases. If those cases are too numerous, it may be time to rethink the whole expression.
<?php
// Always true
if ($a != 1 || $a != 2) { }
// $a == 1 is useless
if ($a == 1 || $a != 2) {}
// Always false
if ($a == 1 && $a == 2) {}
// $a != 2 is useless
if ($a == 1 && $a != 2) {}
?>
Inspired by an article from Andrey Karpov .
See also and Logical Expressions in C/C++. Mistakes Made by Professionals
ext/lua
[Since 0.8.4] - [ -P Extensions/Extlua ] - [ Online docs ]
Extension Lua.
'Lua is a powerful, fast, light-weight, embeddable scripting language.' This extension embeds the lua interpreter and offers an OO-API to lua variables and functions.
<?php
$lua = new Lua();
$lua->eval(<<<CODE
print(2);
CODE
);
?>
See also ext/lua manual and LUA
Uncaught Exceptions
[Since 0.8.4] - [ -P Exceptions/UncaughtExceptions ] - [ Online docs ]
The following exceptions are thrown in the code, but are never caught.
<?php
// This exception is throw, but not caught. It will lead to a fatal error.
if ($message = check_for_error()) {
throw new My\Exception($message);
}
// This exception is throw, and caught.
try {
if ($message = check_for_error()) {
throw new My\Exception($message);
}
} catch (\Exception $e) {
doSomething();
}
?>
Either they will lead to a Fatal Error, or they have to be caught by an including application. This is a valid behavior for libraries, but is not for a final application.
See also and Structuring PHP Exceptions
Same Conditions In Condition
[Since 0.8.4] - [ -P Structures/SameConditions ] - [ Online docs ]
At least two consecutive if/then structures use identical conditions. The latter will probably be ignored.
This analysis returns false positive when there are attempt to fix a situation, or to call an alternative solution.
Conditions that are shared between if structures, but inside a logical OR expression are also detected.
<?php
if ($a == 1) { doSomething(); }
elseif ($b == 1) { doSomething(); }
elseif ($c == 1) { doSomething(); }
elseif ($a == 1) { doSomething(); }
else {}
// Also works on if then else if chains
if ($a == 1) { doSomething(); }
else if ($b == 1) { doSomething(); }
else if ($c == 1) { doSomething(); }
else if ($a == 1) { doSomething(); }
else {}
// Also works on if then else if chains
// Here, $a is common and sufficient in both conditions
if ($a || $b) { doSomething(); }
elseif ($a || $c) { doSomethingElse(); }
// This sort of situation generate false postive.
$config = load_config_from_commandline();
if (empty($config)) {
$config = load_config_from_`file() <https://www.php.net/file>`_;
if (empty($config)) {
$config = load_default_config();
}
}
?>
Return True False
[Since 0.8.4] - [ -P Structures/ReturnTrueFalse ] - [ Online docs ]
These conditional expressions return true/false, depending on the condition. This may be simplified by dropping the control structure altogether.
<?php
if (version_compare($a, $b) >= 0) {
return true;
} else {
return false;
}
?>
This may be simplified with :
<?php
return version_compare($a, $b) >= 0;
?>
This may be applied to assignations and ternary operators too.
<?php
if (version_compare($a, $b) >= 0) {
$a = true;
} else {
$a = false;
}
$a = version_compare($a, $b) >= 0 ? false : true;
?>
Useless Switch
[Since 0.8.4] - [ -P Structures/UselessSwitch ] - [ Online docs ]
This switch has only one case. It may very well be replaced by a ifthen structure.
<?php
switch($a) {
case 1:
doSomething();
break;
}
// Same as
if ($a == 1) {
doSomething();
}
?>
Could Use __DIR__
[Since 0.8.4] - [ -P Structures/CouldUseDir ] - [ Online docs ]
Use __DIR__ constant to access the current file's parent directory.
Avoid using dirname() on __FILE__.
<?php
// Better way
$fp = fopen(__DIR__.'/myfile.txt', 'r');
// compatible, but slow way
$fp = fopen(dirname(__FILE__).'/myfile.txt', 'r');
// Since PHP 5.3
assert(dirname(__FILE__) == __DIR__);
?>
__DIR__ has been introduced in PHP 5.3.0.
See also and Magic Constants
Should Use Coalesce
[Since 0.8.4] - [ -P Php/ShouldUseCoalesce ] - [ Online docs ]
PHP 7 introduced the ?? operator, that replaces longer structures to set default values when a variable is not set.
<?php
// Fetches the request parameter user and results in 'nobody' if it doesn't exist
$username = $_GET['user'] ?? 'nobody';
// equivalent to: $username = isset($_GET['user']) ? $_GET['user'] : 'nobody';
// Calls a hypothetical model-getting function, and uses the provided default if it fails
$model = Model::get($id) ?? $default_model;
// equivalent to: if (($model = Model::get($id)) === NULL) { $model = $default_model; }
?>
Sample extracted from PHP docs Isset Ternary.
See also and New in PHP 7: null coalesce operator
Make Global A Property
[Since 0.8.4] - [ -P Classes/MakeGlobalAProperty ] - [ Online docs ]
Calling global (or $GLOBALS) in methods is slower and less testable than setting the global to a property, and using this property.
Using properties is slightly faster than calling global or $GLOBALS, though the gain is not important.
Setting the property in the constructor (or in a factory), makes the class easier to test, as there is now a single point of configuration.
<?php
// Wrong way
class fooBad {
function x() {
global $a;
$a->do();
// Or $GLOBALS['a']->do();
}
}
class fooGood {
private $bar = null;
function __construct() {
global $bar;
$this->bar = $bar;
// Even better, do this via arguments
}
function x() {
$this->a->do();
}
}
?>
List With Keys
[Since 0.8.4] - [ -P Php/ListWithKeys ] - [ Online docs ]
Setting keys when using list() is a PHP 7.1 feature.
<?php
// PHP 7.1 and later only
list('a' => $a, 'b' => $b) = ['b' => 1, 'c' => 2, 'a' => 3];
?>
If With Same Conditions
[Since 0.8.4] - [ -P Structures/IfWithSameConditions ] - [ Online docs ]
Successive If / then structures that have the same condition may be either merged or have one of the condition changed.
<?php
if ($a == 1) {
doSomething();
}
if ($a == 1) {
doSomethingElse();
}
// May be replaced by
if ($a == 1) {
doSomething();
doSomethingElse();
}
?>
Note that if the values used in the condition have been modified in the first if/then structure, the two distinct conditions may be needed.
<?php
// May not be merged
if ($a == 1) {
// Check that this is really the situation
$a = checkSomething();
}
if ($a == 1) {
doSomethingElse();
}
?>
ext/suhosin
[Since 0.8.4] - [ -P Extensions/Extsuhosin ] - [ Online docs ]
Suhosin extension.
Suhosin (pronounced 'su-ho-shin') is an advanced protection system for PHP installations. It was designed to protect servers and users from known and unknown flaws in PHP applications and the PHP core.
Suhosin was a PHP 5 extension, and it has been ported to PHP 7 and 8, as a separate but eponymous project.
<?php
// sha256 is a ext/suhosin specific function
$sha256 = sha256($string);
?>
See also Suhosin.org and Suhosin snuffleupagus
Throw Functioncall
[Since 0.8.4] - [ -P Exceptions/ThrowFunctioncall ] - [ Online docs ]
The throw keyword expects to use an exception. Calling a function to prepare that exception before throwing it is possible, but forgetting the new keyword is also possible.
<?php
// Forgotten new
throw \RuntimeException('error!');
// Code is OK, function returns an exception
throw getException(ERROR_TYPE, 'error!');
function getException(ERROR_TYPE, $message) {
return new \RuntimeException($messsage);
}
?>
When the new keyword is forgotten, then the class constructor is used as a function name, and now exception is emitted, but an Undefined function fatal error is emitted.
Can't Disable Function
[Since 0.8.4] - [ -P Security/CantDisableFunction ] - [ Online docs ]
This is the list of potentially dangerous PHP functions being used in the code, such as exec() or fsockopen().
eval() is not reported here, as it is not a PHP function, but a language construct : it can't be disabled.
<?php
// This script uses ftp_connect(), therefore, this function shouldn't be disabled.
$ftp = ftp_connect($host, 21);
// This script doesn't use imap_open(), therefore, this function may be disabled.
?>
This analysis is the base for suggesting values for the disable_functions directive.
Functions Using Reference
[Since 0.8.4] - [ -P Functions/FunctionsUsingReference ] - [ Online docs ]
Functions and methods using references in their signature.
<?php
function usingReferences( &$a) {}
class foo {
public function methodUsingReferences($b, &$c = 1) {}
}
?>
Use Instanceof
[Since 0.8.4] - [ -P Classes/UseInstanceof ] - [ Online docs ]
The instanceof operator is a more precise alternative to is_object()
instanceof checks for an variable to be of a class or its parents or the interfaces it implements.
Once instanceof has been used, the actual attributes available (properties, constants, methods) are known, unlike with is_object()
Last, instanceof may be upgraded to Typehint, by moving it to the method signature.
<?php
class Foo {
// Don't use is_object
public function bar($o) {
if (!is_object($o)) { return false; } // Classic argument check
return $o->method();
}
// use instanceof
public function bar($o) {
if ($o instanceof myClass) { // Now, we know which methods are available
return $o->method();
}
return false; } // Default behavior
}
// use of typehinting
// in case $o is not of the right type, exception is raised automatically
public function bar(myClass $o) {
return $o->method();
}
}
?>
instanceof and is_object()
The instanceof operator is also faster than the is_object()
See also Type Operators and is_object
List Short Syntax
[Since 0.8.4] - [ -P Php/ListShortSyntax ] - [ Online docs ]
Usage of short syntax version of list().
<?php
// PHP 7.1 short list syntax
// PHP 7.1 may also use key => value structures with list
[$a, $b, $c] = ['2', 3, '4'];
// PHP 7.0 list syntax
list($a, $b, $c) = ['2', 3, '4'];
?>
Results May Be Missing
[Since 0.8.4] - [ -P Structures/ResultMayBeMissing ] - [ Online docs ]
preg_match() may return empty values, if the search fails. It is important to check for the existence of results before assigning them to another variable, or using it.
<?php
preg_match('/PHP ([0-9\.]+) /', $res, $r);
$s = $r[1];
// $s may end up null if preg_match fails.
?>
Since PHP 7.2, it is possible to use the PREG_UNMATCHED_AS_NULL constant in the flag parameter to avoid this.
Use Nullable Type
[Since 0.8.4] - [ -P Php/UseNullableType ] - [ Online docs ]
The code uses nullable type, available since PHP 7.1.
Nullable Types are an option to type hint : they allow the passing value to be null, or another type.
According to the authors of the feature : 'It is common in many programming languages including PHP to allow a variable to be of some type or null. This null often indicates an error or lack of something to return.'
<?php
function foo(?string $a = 'abc') : ?string {
return $a.b;
}
?>
See also Type declarations and PHP RFC: Nullable Types
Always Positive Comparison
[Since 0.8.4] - [ -P Structures/NeverNegative ] - [ Online docs ]
Some PHP native functions, such as count(), strlen(), or abs() only returns positive or null values.
When comparing them to 0, the following expressions are always true and should be avoided.
<?php
$a = [1, 2, 3];
var_dump(count($a) >= 0);
var_dump(count($a) < 0);
?>
Multiple Exceptions Catch()
[Since 0.8.4] - [ -P Exceptions/MultipleCatch ] - [ Online docs ]
It is possible to have several distinct exceptions class caught by the same catch, preventing code repetition.
This is a new feature since PHP 7.1.
<?php
// PHP 7.1 and more recent
try {
throw new someException();
} catch (Single $s) {
doSomething();
} catch (oneType | anotherType $s) {
processIdentically();
} finally {
}
// PHP 7.0 and older
try {
throw new someException();
} catch (Single $s) {
doSomething();
} catch (oneType $s) {
processIdentically();
} catch (anotherType $s) {
processIdentically();
} finally {
}
?>
This is a backward incompatible feature of PHP 7.1.
Empty Blocks
[Since 0.8.4] - [ -P Structures/EmptyBlocks ] - [ Online docs ]
Full empty block, part of a control structures.
It is recommended to remove those blocks, so as to reduce confusion in the code.
<?php
foreach($foo as $bar) ; // This block seems erroneous
$foobar++;
if ($a === $b) {
doSomething();
} else {
// Empty block. Remove this
}
// Blocks containing only empty expressions are also detected
for($i = 0; $i < 10; $i++) {
;
}
// Although namespaces are not control structures, they are reported here
namespace A;
namespace B;
?>
Throw In Destruct
[Since 0.8.4] - [ -P Classes/ThrowInDestruct ] - [ Online docs ]
According to the manual, Attempting to throw an exception from a destructor (called in the time of script termination) causes a fatal error.
The destructor may be called during the lifespan of the script, but it is not certain. If the exception is thrown later, the script may end up with a fatal error.
Thus, it is recommended to avoid throwing exceptions within the __destruct method of a class.
<?php
// No exception thrown
class Bar {
function __construct() {
throw new Exception('__construct');
}
function __destruct() {
$this->cleanObject();
}
}
// Potential crash
class Foo {
function __destruct() {
throw new Exception('__destruct');
}
}
?>
See also and Constructors and Destructors
Use System Tmp
[Since 0.8.4] - [ -P Structures/UseSystemTmp ] - [ Online docs ]
It is recommended to avoid hardcoding the temporary file. It is better to rely on the system's temporary folder, which is accessible with sys_get_temp_dir().
<?php
// Where the tmp is :
file_put_contents(`sys_get_temp_dir() <https://www.php.net/sys_get_temp_dir>`_.'/tempFile.txt', $content);
// Avoid hard-coding tmp folder :
// On Linux-like systems
file_put_contents('/tmp/tempFile.txt', $content);
// On Windows systems
file_put_contents('C:\WINDOWS\TEMP\tempFile.txt', $content);
?>
See also and PHP: When is /tmp not /tmp?
Dependant Trait
[Since 0.8.4] - [ -P Traits/DependantTrait ] - [ Online docs ]
Traits should be autonomous. It is recommended to avoid depending on methods or properties that should be in the using class.
The following traits make usage of methods and properties, static or not, that are not defined in the trait. This means the host class must provide those methods and properties, but there is no way to enforce this.
This may also lead to dead code : when the trait is removed, the host class have unused properties and methods.
<?php
// autonomous trait : all it needs is within the trait
trait t {
private $p = 0;
function foo() {
return ++$this->p;
}
}
// dependant trait : the host class needs to provide some properties or methods
trait t2 {
function foo() {
return ++$this->p;
}
}
class x {
use t2;
private $p = 0;
}
?>
See also and Classes/DependantAbstractClass
[Since 0.8.4] - [ -P Namespaces/HiddenUse ] - [ Online docs ]
The use expression for namespaces should always be at the beginning of the namespace block.
It is where everyone expect them, and it is less confusing than having them at various levels.
<?php
// This is visible
use A;
class B {}
// This is hidden
use C as D;
class E extends D {
use traitT; // This is a use for a trait
function foo() {
// This is a use for a closure
return function ($a) use ($b) {}
}
}
?>
Should Make Alias
[Since 0.8.4] - [ -P Namespaces/ShouldMakeAlias ] - [ Online docs ]
Long names should be aliased.
Aliased names are easy to read at the beginning of the script; they may be changed at one point, and update the whole code at the same time.
Finally, short names makes the rest of the code readable.
<?php
namespace x\y\z;
use a\b\c\d\e\f\g as Object;
// long name, difficult to read, prone to change.
new a\b\c\d\e\f\g();
// long name, difficult to read, prone to silent dead code if namespace change.
if ($o instanceof a\b\c\d\e\f\g) {
}
// short names Easy to update all at once.
new Object();
if ($o instanceof Object) {
}
?>
Multiple Identical Trait Or Interface
[Since 0.8.4] - [ -P Classes/MultipleTraitOrInterface ] - [ Online docs ]
There is no need to use the same trait, or implements the same interface more than once.
Up to PHP 7.4, this doesn't raise any warning. Traits are only imported once, and interfaces may be implemented as many times as wanted.
Since PHP 7.4, multiple implementations of the same interface in one class is reported at compilation time. It is possible to repeat the implementation in various levels of a class hierarchy (aka, same implements in a class and a parent).
<?php
class foo {
use aTrait, aTrait, aTrait;
use aTrait;
}
class bar implements anInterface, anInterface, anInterface {
}
?>
See also and Interfaces/AlreadyParentsInterface
Multiple Alias Definitions
[Since 0.8.4] - [ -P Namespaces/MultipleAliasDefinitions ] - [ Online docs ]
Some aliases are representing different classes across the repository. This leads to potential confusion.
Across an application, it is recommended to use the same namespace for one alias. Failing to do this lead to the same keyword to represent different values in different files, with different behavior. Those are hard to find bugs.
<?php
namespace A {
use d\d; // aka D
}
// Those are usually in different files, rather than just different namespaces.
namespace B {
use b\c as D; // also D. This could be named something else
}
?>
Nested Ifthen
[Since 0.8.4] - [ -P Structures/NestedIfthen ] - [ Online docs ]
Three levels of ifthen is too much. The method should be split into smaller functions.
<?php
function foo($a, $b) {
if ($a == 1) {
// Second level, possibly too much already
if ($b == 2) {
}
}
}
function bar($a, $b, $c) {
if ($a == 1) {
// Second level.
if ($b == 2) {
// Third level level.
if ($c == 3) {
// Too much
}
}
}
}
?>
See also and Structures/TooManyIf
Cast To Boolean
[Since 0.8.4] - [ -P Structures/CastToBoolean ] - [ Online docs ]
This expression may be reduced by casting to boolean type.
<?php
$variable = $condition == 'met' ? 1 : 0;
// Same as
$variable = (bool) $condition == 'met';
$variable = $condition == 'met' ? 0 : 1;
// Same as (Note the condition inversion)
$variable = (bool) $condition != 'met';
// also, with an indentical condition
$variable = !(bool) $condition == 'met';
// This also works with straight booleans expressions
$variable = $condition == 'met' ? true : false;
// Same as
$variable = $condition == 'met';
?>
Failed Substr Comparison
[Since 0.8.4] - [ -P Structures/FailingSubstrComparison ] - [ Online docs ]
The extracted string must be of the size of the compared string.
This is also true for negative lengths.
<?php
// Possible comparison : strings and substr results are the same
if (substr($a, 0, 3) === 'abc') { }
if (substr($b, 4, 3) === 'abc') { }
// Always failing : substr will probably provide a longer string
if (substr($a, 0, 3) === 'ab') { }
if (substr($a, 3, -3) === 'ab') { }
// Omitted in this analysis
if (substr($a, 0, 3) !== 'ab') { }
?>
This rule raise a false positive when the variable is already smaller than the expected substr() results.
This rule doesn't apply to mb_substr() and iconv_substr() : those functions use the character size, not the byte size.
Should Use Ternary Operator
[Since 0.8.5] - [ -P Structures/ShouldMakeTernary ] - [ Online docs ]
Ternary operators are the best when assigning values to a variable.
They are less verbose, compatible with assignation and easier to read.
<?php
// verbose if then structure
if ($a == 3) {
$b = 2;
} else {
$b = 3;
}
// compact ternary call
$b = ($a == 3) ? 2 : 3;
// verbose if then structure
// Works with short assignations and simple expressions
if ($a != 3) {
$b += 2 - $a * 4;
} else {
$b += 3;
}
// compact ternary call
$b += ($a != 3) ? 2 - $a * 4 : 3;
?>
See also Ternary Operator and Shorthand comparisons in PHP
Unused Returned Value
[Since 0.8.5] - [ -P Functions/UnusedReturnedValue ] - [ Online docs ]
The function called returns a value, which is ignored.
Usually, this is a sign of dead code, or a missed check on the results of the functioncall. At times, it may be a valid call if the function has voluntarily no return value.
It is recommended to add a check on the return value, or remove the call.
<?php
// simplest form
function foo() {
return 1;
}
foo();
// In case of multiple return, any one that returns something means that return value is meaningful
function bar() {
if (rand(0, 1)) {
return 1;
} else {
return ;
}
}
bar();
?>
Note that this analysis ignores functions that return void (same meaning that PHP 7.1 : return ; or no return in the function body).
Modernize Empty With Expression
[Since 0.8.6] - [ -P Structures/ModernEmpty ] - [ Online docs ]
empty() accepts expressions as argument. This feature was added in PHP 5.5.
There is no need to store the expression in a variable before testing, unless it is reused later.
<?php
// PHP 5.5+ `empty() <https://www.php.net/empty>`_ usage
if (empty(foo($b . $c))) {
doSomethingWithoutA();
}
// Compatible `empty() <https://www.php.net/empty>`_ usage
$a = foo($b . $c);
if (empty($a)) {
doSomethingWithoutA();
}
// $a2 is reused, storage is legit
$a2 = strtolower($b . $c);
if (empty($a2)) {
doSomething();
} else {
echo $a2;
}
?>
See also empty()
Use Positive Condition
[Since 0.8.6] - [ -P Structures/UsePositiveCondition ] - [ Online docs ]
Whenever possible, use a positive condition.
Positive conditions are easier to understand, and lead to less understanding problems.
Negative conditions are not reported when else is not present.
<?php
// This is a positive condition
if ($a == 'b') {
doSomething();
} else {
doSomethingElse();
}
if (!empty($a)) {
doSomething();
} else {
doSomethingElse();
}
// This is a negative condition
if ($a == 'b') {
doSomethingElse();
} else {
doSomething();
}
// No need to force $a == 'b' with empty else
if ($a != 'b') {
doSomethingElse();
}
?>
See also Double negatives should not not be avoided and How To Write Conditional Statements in PHP
Drop Else After Return
[Since 0.8.6] - [ -P Structures/DropElseAfterReturn ] - [ Online docs ]
Avoid else clause when the then clause returns, but not the else. And vice-versa.
This way, the else block disappears, and is now the main sequence of the function.
This is also true if else has a return, and then not. When doing so, don't forget to reverse the condition.
<?php
// drop the else
if ($a) {
return $a;
} else {
doSomething();
}
// drop the then
if ($b) {
doSomething();
} else {
return $a;
}
// return in else and then
if ($a3) {
return $a;
} else {
$b = doSomething();
return $b;
}
?>
Use ::Class Operator
[Since 0.8.7] - [ -P Classes/UseClassOperator ] - [ Online docs ]
Use ::class to hardcode class names, instead of strings.
This is actually faster than strings, which are parsed at execution time, while ::class is compiled, making it faster to execute.
::class operator is also able to handle use expressions, including aliases and local namespace. The code is easier to maintain. For example, the target class's namespace may be renamed, without changing the ::class , while the string must be updated.
::class operator works with self and static keywords.
<?php
namespace foo\bar;
use foo\bar\X as B;
class X {}
$className = '\foo\bar\X';
$className = foo\bar\X::class;
$className = B\X;
$object = new $className;
?>
This is not possible when building the name of the class with concatenation.
This is a micro-optimization. This also helps static analysis, as it gives more information at compile time to analyse.
See also and ::class
ext/rar
[Since 0.8.7] - [ -P Extensions/Extrar ] - [ Online docs ]
Extension RAR.
Rar is a powerful and effective archiver created by Eugene Roshal. This extension gives you possibility to read Rar archives but doesn't support writing Rar archives, because this is not supported by the UnRar library and is directly prohibited by its license.
<?php
$arch = RarArchive::open(example.rar);
if ($arch === FALSE)
die(Cannot open example.rar);
$entries = $arch->getEntries();
if ($entries === FALSE)
die(Cannot retrieve entries);
?>
See also Rar archiving and rarlabs
Don't Echo Error
[Since 0.8.7] - [ -P Security/DontEchoError ] - [ Online docs ]
It is recommended to avoid displaying error messages directly to the browser.
PHP's uses the display_errors directive to control display of errors to the browser. This must be kept to off when in production.
<?php
// Inside a 'or' test
mysql_connect('localhost', $user, $pass) or die(mysql_error());
// Inside a if test
$result = pg_query( $db, $query );
if( !$result )
{
echo Erreur SQL: . pg_error();
exit;
}
// Changing PHP configuration
ini_set('display_errors', 1);
// This is also a security error : 'false' means actually true.
ini_set('display_errors', 'false');
?>
Error messages should be logged, but not displayed.
See also Error reporting and List of php.ini directives
Useless Type Casting
[Since 0.8.7] - [ -P Structures/UselessCasting ] - [ Online docs ]
There is no need to cast already typed values.
<?php
// trim always returns a string : cast is useless
$a = (string) trim($b);
// strpos doesn't always returns an integer : cast is useful
$a = (boolean) strpos($b, $c);
// comparison don't need casting, nor parenthesis
$c = (bool) ($b > 2);
function foo(array $a) {
foreach((array) $a as $b) {
// doSomething
}
}
?>
Typed values, such as properties, do not have to be cast again, as the engine always ensures their type.
Typed arguments are variables : after the initial check at method call time, they might change value and type. Those extra cast may then carry some value, although changing the type of an incoming value is not recommended.
See also Type juggling and Structures/MultipleTypeVariable
No isset() With empty()
[Since 0.8.7] - [ -P Structures/NoIssetWithEmpty ] - [ Online docs ]
empty() actually does the job of isset() too.
From the manual : No warning is generated if the variable does not exist. That means empty() is essentially the concise equivalent to !isset($var) || $var == false. The main difference is that isset() only works with variables, while empty() works with other structures, such as constants.
<?php
// Enough validation
if (!empty($a)) {
doSomething();
}
// Too many tests
if (isset($a) && !empty($a)) {
doSomething();
}
?>
See also Isset and empty
Useless Check
[Since 0.8.9] - [ -P Structures/UselessCheck ] - [ Online docs ]
There is no need to check the size of an array content before using foreach. Foreach() applies a test on the source, and skips the loop if no element is found.
<?php
// Checking for type is good.
if (is_array($array)) {
foreach($array as $a) {
doSomething($a);
}
}
// Foreach on empty arrays doesn't start. Checking is useless
if (!empty($array)) {
foreach($array as $a) {
doSomething($a);
}
}
?>
This analysis checks for conditions with sizeof() and count(). Conditions with isset() and empty() are omitted : they also check for the variable existence, and thus, offer extra coverage.
See also foreach.
Bail Out Early
[Since 0.8.9] - [ -P Structures/BailOutEarly ] - [ Online docs ]
When using conditions, it is recommended to quit in the current context, and avoid the else clause altogether.
The main benefit is to make clear the method applies a condition, and stop immediately when this condition is not satisfied.
The main sequence is then focused on the important code.
This analysis works with the break , continue , throw and goto keywords too, depending on situations.
<?php
// Bailing out early, low level of indentation
function foo1($a) {
if ($a > 0) {
return false;
}
$a++;
return $a;
}
// Works with continue too
foreach($array as $a => $b) {
if ($a > 0) {
continue false;
}
$a++;
return $a;
}
// No need for else
function foo2($a) {
if ($a > 0) {
return false;
} else {
$a++;
}
return $a;
}
// No need for else : return goes into then.
function foo3($a) {
if ($a < 0) {
$a++;
} else {
return false;
}
return $a;
}
// Make a return early, and make the condition visible.
function foo3($a) {
if ($a < 0) {
$a++;
methodcall();
functioncall();
}
}
?>
See also Avoid nesting too deeply and return early (part 1) and Avoid nesting too deeply and return early (part 2)
Dont Change The Blind Var
[Since 0.8.9] - [ -P Structures/DontChangeBlindKey ] - [ Online docs ]
When using a foreach(), the blind variables hold a copy of the original value. It is confusing to modify them, as it seems that the original value may be changed.
When actually changing the original value, use the reference in the foreach definition to make it obvious, and save the final reassignation.
When the value has to be prepared before usage, then save the filtered value in a separate variable. This makes the clean value obvious, and preserve the original value for a future usage.
<?php
// $bar is duplicated and kept
$foo = [1, 2, 3];
foreach($foo as $bar) {
// $bar is updated but its original value is kept
$nextBar = $bar + 1;
print $bar . ' => ' . ($nextBar) . PHP_EOL;
foobar($nextBar);
}
// $bar is updated and lost
$foo = [1, 2, 3];
foreach($foo as $bar) {
// $bar is updated but its final value is lost
print $bar . ' => ' . (++$bar) . PHP_EOL;
// Now that $bar is reused, it is easy to confuse its value
foobar($bar);
}
// $bar is updated and kept
$foo = [1, 2, 3];
foreach($foo as &$bar) {
// $bar is updated and keept
print $bar . ' => ' . (++$bar) . PHP_EOL;
foobar($bar);
}
?>
Avoid Using stdClass
[Since 0.9.1] - [ -P Php/UseStdclass ] - [ Online docs ]
stdClass is the default class for PHP. It is instantiated when PHP needs to return a object, but no class is specifically available.
It is recommended to avoid instantiating this class. Some PHP or frameworks functions, such as json_encode(), do return them : this is fine, although it is reported here.
<?php
$json = '{a:1,b:2,c:3}';
$object = json_decode($json);
// $object is a stdClass, as returned by json_decode
// Fast building of $o
$a = [];
$a['a'] = 1;
$a['b'] = 2;
$a['c'] = 3;
json_encode( (object) $a);
// Slow building of $o
$o = new stdClass();
$o->a = 1;
$o->b = 2;
$o->c = 3;
json_encode($o);
?>
If you need a stdClass object, it is faster to build it as an array, then cast it, than instantiate stdClass . This is a micro-optimisation.
ext/nsapi
[Since 0.9.2] - [ -P Extensions/Extnsapi ] - [ Online docs ]
NSAPI specific functions calls.
These functions are only available when running PHP as a NSAPI module in Netscape/iPlanet/Sun webservers.
<?php
// This scripts depends on ext/nsapi
if (ini_get('nsapi.read_timeout') < 60) {
doSomething();
}
?>
See also and Sun, iPlanet and Netscape servers on Sun Solaris
ext/newt
[Since 0.8.4] - [ -P Extensions/Extnewt ] - [ Online docs ]
Newt PHP CLI extension.
This is a PHP language extension for RedHat Newt library, a terminal-based window and widget library for writing applications with user friendly interface.
<?php
newt_init ();
newt_cls ();
newt_draw_root_text (0, 0, Test Mode Setup Utility 1.12);
newt_push_help_line (null);
newt_get_screen_size ($rows, $cols);
newt_open_window ($rows/2-17, $cols/2-10, 34, 17, Choose a Tool);
$form = newt_form ();
$list = newt_listbox (3, 2, 10);
foreach (array (
Authentication configuration,
Firewall configuration,
Mouse configuration,
Network configuration,
Printer configuration,
System services) as $l_item)
{
newt_listbox_add_entry ($list, $l_item, $l_item);
}
$b1 = newt_button (5, 12, Run Tool);
$b2 = newt_button (21, 12, Quit);
newt_form_add_component ($form, $list);
newt_form_add_components ($form, array($b1, $b2));
newt_refresh ();
newt_run_form ($form);
newt_pop_window ();
newt_pop_help_line ();
newt_finished ();
newt_form_destroy ($form);
?>
See also and Newt
ext/ncurses
[Since 0.8.4] - [ -P Extensions/Extncurses ] - [ Online docs ]
Extension ncurses (CLI).
ncurses (new curses) is a free software emulation of curses in System V Rel 4.0 (and above).
<?php
ncurses_init();
ncurses_start_color();
ncurses_init_pair(1, NCURSES_COLOR_GREEN, NCURSES_COLOR_BLACK);
ncurses_init_pair(2, NCURSES_COLOR_RED, NCURSES_COLOR_BLACK);
ncurses_init_pair(3, NCURSES_COLOR_WHITE, NCURSES_COLOR_BLACK);
ncurses_color_set(1);
ncurses_addstr('OK ');
ncurses_color_set(3);
ncurses_addstr('Success!'.PHP_EOL);
ncurses_color_set(2);
ncurses_addstr('FAIL ');
ncurses_color_set(3);
ncurses_addstr('Success!'.PHP_EOL);
?>
See also Ncurses Terminal Screen Control and Ncurses
Use Composer Lock
[Since 0.9.2] - [ -P Composer/UseComposerLock ] - [ Online docs ]
Reports if the composer.lock was committed to the archive.
See also and Composer
Too Many Local Variables
[Since 0.9.2] - [ -P Functions/TooManyLocalVariables ] - [ Online docs ]
Too many local variables were found in the methods. When over 15 variables are found in such a method, a violation is reported.
Local variables exclude globals (imported with global) and arguments. Local variable include static variables.
When too many variables are used in a function, it is a code smells. The function is trying to do too much and needs extra space for juggling.
Beyond 15 variables, it becomes difficult to keep track of their name and usage, leading to confusion, overwriting or hijacking.
<?php
// This function is OK : 3 vars are arguments, 3 others are globals.
function a20a3g3($a1, $a2, $a3) {
global $a4, $a5, $a6;
$a1 = 1;
$a2 = 2;
$a3 = 3 ;
$a4 = 4 ;
$a5 = 5 ;
$a6 = 6 ;
$a7 = 7 ;
$a8 = 8 ;
$a9 = 9 ;
$a10 = 10;
$a11 = 11;
$a12 = 12;
$a13 = 13 ;
$a14 = 14 ;
$a15 = 15 ;
$a16 = 16 ;
$a17 = 17 ;
$a18 = 18 ;
$a19 = 19 ;
$a20 = 20;
}
// This function has too many variables
function a20() {
$a1 = 1;
$a2 = 2;
$a3 = 3 ;
$a4 = 4 ;
$a5 = 5 ;
$a6 = 6 ;
$a7 = 7 ;
$a8 = 8 ;
$a9 = 9 ;
$a10 = 10;
$a11 = 11;
$a12 = 12;
$a13 = 13 ;
$a14 = 14 ;
$a15 = 15 ;
$a16 = 16 ;
$a17 = 17 ;
$a18 = 18 ;
$a19 = 19 ;
$a20 = 20;
}
?>
Illegal Name For Method
[Since 0.9.2] - [ -P Classes/WrongName ] - [ Online docs ]
PHP has reserved usage of methods starting with __ for magic methods. It is recommended to avoid using this prefix, to prevent confusions.
<?php
class foo{
// Constructor
function __construct() {}
// Constructor's typo
function __constructor() {}
// Illegal function name, even as private
private function __bar() {}
}
?>
See also and Magic Methods
String
[Since 0.9.4] - [ -P Extensions/Extstring ] - [ Online docs ]
Strings in PHP. Strings are part of the core of PHP, and are not a separate extension.
<?php
$str = Mary Had A Little Lamb and She LOVED It So;
$str = strtolower($str);
echo $str; // Prints mary had a little lamb and she loved it so
?>
See also and String functions
ext/mongodb
[Since 0.9.5] - [ -P Extensions/Extmongodb ] - [ Online docs ]
Extension MongoDb.
Do not mistake with extension Mongo, the previous version.
Mongodb driver supports both PHP and HHVM and is developed atop the libmongoc and libbson libraries.
<?php
require 'vendor/autoload.php'; // include Composer's autoloader
$client = new MongoDB\Client(mongodb://localhost:27017);
$collection = $client->demo->beers;
$result = $collection->insertOne( [ 'name' => 'Hinterland', 'brewery' => 'BrewDog' ] );
echo Inserted with Object ID {$result->getInsertedId()};
?>
See also MongoDB driver and MongdDb
Long Arguments
[Since 0.9.7] - [ -P Structures/LongArguments ] - [ Online docs ]
Long arguments should be put in variable, to preserve readability.
When literal arguments are too long, they break the hosting structure by moving the next argument too far on the right. Whenever possible, long arguments should be set in a local variable to keep the readability.
<?php
// Now the call to foo() is easier to read.
$reallyBigNumber = <<<BIGNUMBER
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
BIGNUMBER
foo($reallyBigNumber, 2, '12345678901234567890123456789012345678901234567890');
// where are the next arguments ?
foo('123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890', 2, '123456789012345678901234567890123456789012345678901234567890');
// This is still difficult to read
foo(<<<BIGNUMBER
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
BIGNUMBER
, 2, '123456789012345678901234567890123456789012345678901234567890');
?>
Literal strings and heredoc strings, including variables, that are over 50 chars longs are reported here.
Assigned Twice
[Since 0.9.8] - [ -P Variables/AssignedTwiceOrMore ] - [ Online docs ]
The same variable is assigned twice in the same function.
While this is possible and quite common, it is also a good practice to avoid changing a value from one literal to another. It is far better to assign the new value to
Incremental changes to a variables are not reported here.
<?php
function foo() {
// incremental changes of $a;
$a = 'a';
$a++;
$a = uppercase($a);
$b = 1;
$c = bar($b);
// B changed its purpose. Why not call it $d?
$b = array(1,2,3);
// This is some forgotten debug
$e = $config->getSomeList();
$e = array('OneElement');
}
?>
Error_Log() Usage
[Since 0.10.0] - [ -P Php/ErrorLogUsage ] - [ Online docs ]
Usage of error_log() function. This leads to checking the configuration of error_log in the PHP configuration directives.
<?php
error_log(logging message\n);
?>
No Boolean As Default
[Since 0.10.0] - [ -P Functions/NoBooleanAsDefault ] - [ Online docs ]
Default values should always be set up with a constant name.
Class constants and constants improve readability when calling the methods or comparing values and statuses.
<?php
const CASE_INSENSITIVE = true;
const CASE_SENSITIVE = false;
function foo($case_insensitive = true) {
// doSomething()
}
// Readable code
foo(CASE_INSENSITIVE);
foo(CASE_SENSITIVE);
// unreadable code : is true case insensitive or case sensitive ?
foo(true);
foo(false);
?>
See also FlagArgument and Clean code: The curse of a boolean parameter
SQL queries
[Since 0.10.1] - [ -P Type/Sql ] - [ Online docs ]
SQL queries, detected in literal strings.
SQL queries are detected with keywords, inside literals or concatenations.
<?php
// SQL in a string
$query = 'SELECT name FROM users WHERE id = 1';
// SQL in a concatenation
$query = 'SELECT name FROM '.$table_users.' WHERE id = 1';
// SQL in a Heredoc
$query = <<<SQL
SELECT name FROM $table_users WHERE id = 1
SQL;
?>
ext/libsodium
[Since 0.10.2] - [ -P Extensions/Extlibsodium ] - [ Online docs ]
Extension for libsodium : in PECL until PHP 7.2, and in core ever since.
The Sodium crypto library (libsodium) is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more.
Sodium supports a variety of compilers and operating systems, including Windows (with MinGW or Visual Studio, x86 and x64), iOS and Android.
The design choices emphasize security, and "magic constants" have clear rationales.
<?php
// Example from the docs : https://paragonie.com/book/pecl-libsodium/read/06-hashing.md#crypto-generichash
// Fast, unkeyed hash function.
// Can be used as a secure replacement for MD5
$h = \Sodium\crypto_generichash('msg');
// Fast, keyed hash function.
// The key can be of any length between \Sodium\CRYPTO_GENERICHASH_KEYBYTES_MIN
// and \Sodium\CRYPTO_GENERICHASH_KEYBYTES_MAX, in bytes.
// \Sodium\CRYPTO_GENERICHASH_KEYBYTES is the recommended length.
$h = \Sodium\crypto_generichash('msg', $key);
// Fast, keyed hash function, with user-chosen output length, in bytes.
// Output length can be between \Sodium\CRYPTO_GENERICHASH_BYTES_MIN and
// \Sodium\CRYPTO_GENERICHASH_BYTES_MAX.
// \Sodium\CRYPTO_GENERICHASH_BYTES is the default length.
$h = \Sodium\crypto_generichash('msg', $key, 64);
?>
See also PHP extension for libsodium and Using Libsodium in PHP Projects
Forgotten Thrown
[Since 0.10.2] - [ -P Exceptions/ForgottenThrown ] - [ Online docs ]
An exception is instantiated, but not thrown.
<?php
class MyException extends \Exception { }
if ($error !== false) {
// This looks like 'throw' was omitted
new MyException();
}
?>
Multiple Alias Definitions Per File
[Since 0.10.3] - [ -P Namespaces/MultipleAliasDefinitionPerFile ] - [ Online docs ]
Avoid aliasing the same name with different aliases. This leads to confusion.
<?php
// first occurrence
use name\space\ClasseName;
// when this happens, several other uses are mentioned
// name\space\ClasseName has now two names
use name\space\ClasseName as anotherName;
?>
See also and `Namespaces/MultipleAliasDefinition`_
__DIR__ Then Slash
[Since 0.10.3] - [ -P Structures/DirThenSlash ] - [ Online docs ]
__DIR__ must be concatenated with a string starting with /.
The magic constant __DIR__ holds the name of the current directory, without final /. When it is used to build path, then the following path fragment must start with /. Otherwise, two directories names will be merged together.
<?php
// __DIR__ = /a/b/c
// $filePath = /a/b/c/g.php
// /a/b/c/d/e/f.txt : correct path
echo __DIR__.'/d/e/f.txt';
echo dirname($filePath).'/d/e/f.txt';
// /a/b/cd/e/f.txt : most probably incorrect path
echo __DIR__.'d/e/f.txt';
echo dirname($filePath).'d/e/f.txt';
?>
self, parent, static Outside Class
[Since 0.10.3] - [ -P Classes/NoPSSOutsideClass ] - [ Online docs ]
self, parent and static should be called inside a class or trait. PHP lint won't report those situations.
self, parent and static may be used in a trait : their actual value will be only known at execution time, when the trait is used.
<?php
// In the examples, self, parent and static may be used interchangeably
// This raises a Fatal error
//Fatal error: Uncaught Error: Cannot access static:: when no class scope is active
new static();
// static calls
echo self::CONSTANTE;
echo self::$property;
echo self::method();
// as a type hint
function foo(static $x) {
doSomething();
}
// as a instanceof
if ($x instanceof static) {
doSomething();
}
?>
Such syntax problem is only revealed at execution time : PHP raises a Fatal error.
The origin of the problem is usually a method that was moved outside a class, at least temporarily.
Closures and arrow functions are reported here, though they might be rebound with a valid context before execution.
See also and Scope Resolution Operator (::)
Used Once Property
[Since 0.10.3] - [ -P Classes/UsedOnceProperty ] - [ Online docs ]
Property used once in their defining class.
Properties used in one method only may be used several times, and read only. This may be a class constant. Such properties are meant to be overwritten by an extending class, and that's possible with class constants.
Setting properties with default values is a good way to avoid littering the code with literal values, and provide a single point of update (by extension, or by hardcoding) for all those situations. A constant is definitely better suited for this task.
<?php
class foo {
private $defaultCols = '*';
cont DEFAULT_COLUMNS = '*';
// $this->defaultCols holds a default value. Should be a constant.
function bar($table, $cols) {
// This is necessary to activate usage of default values
if (empty($cols)) {
$cols = $this->defaultCols;
}
$res = $this->query('SELECT '.$cols.' FROM '.$table);
// ....
}
// Upgraded version of bar, with default values
function bar2($table, $cols = self::DEFAULT_COLUMNS) {
$res = $this->query('SELECT '.$cols.' FROM '.$table);
// .....
}
}
?>
Property Used In One Method Only
[Since 0.10.3] - [ -P Classes/PropertyUsedInOneMethodOnly ] - [ Online docs ]
Properties should be used in several methods. When a property is used in only one method, this should have be of another shape.
Properties used in one method only may be used several times, and read only. This may be a class constant. Such properties are meant to be overwritten by an extending class, and that's possible with class constants.
Properties that read and written may be converted into a variable, static to the method. This way, they are kept close to the method, and do not pollute the object's properties.
<?php
class foo {
private $once = 1;
const ONCE = 1;
private $counter = 0;
function bar() {
// $this->once is never used anywhere else.
someFunction($this->once);
someFunction(self::ONCE); // Make clear that it is a
}
function bar2() {
static $localCounter = 0;
$this->counter++;
// $this->once is only used here, for distinguising calls to someFunction2
if ($this->counter > 10) { // $this->counter is used only in bar2, but it may be used several times
return false;
}
someFunction2($this->counter);
// $localCounter keeps track for all the calls
if ($localCounter > 10) {
return false;
}
someFunction2($localCounter);
}
}
?>
This analysis consider that using the current object with a cast or with the get_object_vars() function is also a usage, and skip those properties.
Note : properties used only once are not returned by this analysis. They are omitted, and are available in the analysis `Used Once Property`_.
ext/ds
[Since 0.10.4] - [ -P Extensions/Extds ] - [ Online docs ]
Extension Data Structures : Data structures.
<?php
$vector = new \Ds\Vector();
$vector->push('a');
$vector->push('b', 'c');
$vector[] = 'd';
print_r($vector);
?>
See also and Efficient data structures for PHP 7
No Need For Else
[Since 0.10.4] - [ -P Structures/NoNeedForElse ] - [ Online docs ]
Else is not needed when the Then ends with a break. A break may be the following keywords : break, continue, return, goto. Any of these send the execution somewhere in the code. The else block is then executed as the main sequence, only if the condition fails.
<?php
function foo() {
// Else may be in the main sequence.
if ($a1) {
return $a1;
} else {
$a++;
}
// Same as above, but negate the condition : if (!$a2) { return $a2; }
if ($a2) {
$a++;
} else {
return $a2;
}
// This is OK
if ($a3) {
return;
}
// This has no break
if ($a4) {
$a++;
} else {
$b++;
}
// This has no else
if ($a5) {
$a++;
}
}
?>
See also and Object Calisthenics, rule # 2
Strange Name For Constants
[Since 0.10.5] - [ -P Constants/StrangeName ] - [ Online docs ]
Those constants looks like a typo from other names.
<?php
// This code looks OK : DIRECTORY_SEPARATOR is a native PHP constant
$path = $path . DIRECTORY_SEPARATOR . $file;
// Strange name DIRECOTRY_SEPARATOR
$path = $path . DIRECOTRY_SEPARATOR . $file;
?>
Too Many Finds
[Since 0.10.5] - [ -P Classes/TooManyFinds ] - [ Online docs ]
Too many methods called 'find*' in this class. It is may be time to consider the Specification pattern.
<?php
// quite a fishy interface
interface UserInterface {
public function findByEmail($email);
public function findByUsername($username);
public function findByFirstName($firstname);
public function findByLastName($lastname);
public function findByName($name);
public function findById($id);
public function insert($user);
public function update($user);
}
?>
See also On Taming Repository Classes in Doctrine and specifications
Use Cookies
[Since 0.10.6] - [ -P Php/UseCookies ] - [ Online docs ]
This code source uses cookies.
Cookie usage is spotted with the usage of setcookie(), setrawcookie() and header() with the 'Set-Cookie' header.
<?php
header('Set-Cookie: '.$name.'='.$value.'; EXPIRES'.$date.';');
// From the PHP Manual :
setcookie('TestCookie3', $value, time()+3600, '/~rasmus/', 'example.com', 1);
?>
See also and Cookies
Should Use SetCookie()
[Since 0.10.6] - [ -P Php/UseSetCookie ] - [ Online docs ]
Use setcookie() or setrawcookie(). Avoid using header() to do so, as the PHP native functions are more convenient and easier to spot during a refactoring.
setcookie() applies some encoding internally, for the value of the cookie and the date of expiration. Rarely, this encoding has to be skipped : then, use setrawencoding().
Both functions help by giving a checklist of important attributes to be used with the cookie.
<?php
// same as below
setcookie(myCookie, 'chocolate', time()+3600, /, , true, true);
// same as above. Slots for path and domain are omitted, but should be used whenever possible
header('Set-Cookie: myCookie=chocolate; Expires='.date('r', (time()+3600)).'; Secure; HttpOnly');
?>
See also Set-Cookie and setcookie
Check All Types
[Since 0.10.6] - [ -P Structures/CheckAllTypes ] - [ Online docs ]
When checking for type, avoid using else. Mention explicitly all tested types, and raise an exception when all available options have been exhausted : after all, this is when the code doesn't know how to handle the datatype.
PHP has a short list of scalar types : null, boolean, integer, real, strings, object, resource and array. When a variable is not holding one the the type, then it may be of any other type.
Most of the time, when using a simple is_string() / else test, this is relying on the conception of the code. By construction, the arguments may be one of two types : array or string.
What happens often is that in case of failure in the code (database not working, another class not checking its results), a third type is pushed to the structure, and it ends up breaking the execution.
The safe way is to check the various types all the time, and use the default case (here, the else) to throw exception() or test an assertion and handle the special case.
<?php
// hasty version
if (is_array($argument)) {
$out = $argument;
} else {
// Here, $argument is NOT an array. What if it is an object ? or a NULL ?
$out = array($argument);
}
// Safe type checking : do not assume that 'not an array' means that it is the other expected type.
if (is_array($argument)) {
$out = $argument;
} elseif (is_string($argument)) {
$out = array($argument);
} else {
assert(false, '$argument is not an array nor a string, as expected!');
}
?>
Using is_callable(), is_iterable() with this structure is fine : when variable is callable or not, while a variable is an integer or else.
Using a type test without else is also accepted here. This is a special treatment for this test, and all others are ignored. This aspect may vary depending on situations and projects.
Missing Cases In Switch
[Since 0.10.7] - [ -P Structures/MissingCases ] - [ Online docs ]
It seems that some cases are missing in this switch structure.
When comparing two different switch() structures, it appears that some cases are missing in one of them. The set of cases are almost identical, but one of the values are missing.
Switch() structures using strings as literals are compared in this analysis. When the discrepancy between two lists is below 25%, both switches are reported.
<?php
// This switch operates on a, b, c, d and default
switch($a) {
case 'a': doSomethingA(); break 1;
case 'b': doSomethingB(); break 1;
case 'c': doSomethingC(); break 1;
case 'd': doSomethingD(); break 1;
default: doNothing();
}
// This switch operates on a, b, d and default
switch($o->p) {
case 'a': doSomethingA(); break 1;
case 'b': doSomethingB(); break 1;
case 'd': doSomethingD(); break 1;
default: doNothing();
}
?>
In the example, one may argue that the 'c' case is actually handled by the 'default' case. Otherwise, business logic may request that omission.
Group Use Declaration
[Since 0.10.7] - [ -P Php/GroupUseDeclaration ] - [ Online docs ]
The group use declaration is used in the code.
<?php
// Adapted from the RFC documentation
// Pre PHP 7 code
use some\name_space\ClassA;
use some\name_space\ClassB;
use some\name_space\ClassC as C;
use function some\name_space\fn_a;
use function some\name_space\fn_b;
use function some\name_space\fn_c;
use const some\name_space\ConstA;
use const some\name_space\ConstB;
use const some\name_space\ConstC;
// PHP 7+ code
use some\name_space\{ClassA, ClassB, ClassC as C};
use function some\name_space\{fn_a, fn_b, fn_c};
use const some\name_space\{ConstA, ConstB, ConstC};
?>
See also Group Use Declaration RFC and Using namespaces: Aliasing/Importing
Repeated Regex
[Since 0.10.9] - [ -P Structures/RepeatedRegex ] - [ Online docs ]
Repeated regex should be centralized.
When a regex is repeatedly used in the code, it is getting harder to update.
<?php
// Regex used several times, at least twice.
preg_match('/^abc_|^square$/i', $_GET['x']);
//.......
preg_match('/^abc_|^square$/i', $row['name']);
// This regex is dynamically built, so it is not reported.
preg_match('/^circle|^'.$x.'$/i', $string);
// This regex is used once, so it is not reported.
preg_match('/^circle|^square$/i', $string);
?>
Regex that are repeated at least once (aka, used twice or more) are reported. Regex that are dynamically build are not reported.
No Class In Global
[Since 0.10.9] - [ -P Php/NoClassInGlobal ] - [ Online docs ]
Avoid defining structures in Global namespace. Always prefer using a namespace. This will come handy later, either when publishing the code, or when importing a library, or even if PHP reclaims that name.
<?php
// Code prepared for later
namespace Foo {
class Bar {}
}
// Code that may conflict with other names.
namespace {
class Bar {}
}
?>
Crc32() Might Be Negative
[Since 0.11.0] - [ -P Php/Crc32MightBeNegative ] - [ Online docs ]
crc32() may return a negative number, on 32 bits platforms.
According to the manual : Because PHP\'s integer type is signed many CRC32 checksums will result in negative integers on 32 bits platforms. On 64 bits installations, all crc32() results will be positive integers though.
<?php
// display the checksum with %u, to make it unsigned
echo sprintf('%u', crc32($str));
// turn the checksum into an unsigned hexadecimal
echo dechex(crc32($str));
// avoid concatenating crc32 to a string, as it may be negative on 32bits platforms
echo 'prefix'.crc32($str);
?>
See also and `crc32()
Could Use str_repeat()
[Since 0.11.0] - [ -P Structures/CouldUseStrrepeat ] - [ Online docs ]
Use str_repeat() or str_pad() instead of making a loop.
Making a loop to repeat the same concatenation is actually much longer than using str_repeat(). As soon as the loop repeats more than twice, str_repeat() is much faster. With arrays of 30, the difference is significant, though the whole operation is short by itself.
<?php
// This adds 7 'e' to $x
$x .= str_repeat('e', 7);
// This is the same as above,
for($a = 3; $a < 10; ++$a) {
$x .= 'e';
}
// here, $default must contains 7 elements to be equivalent to the previous code
foreach($default as $c) {
$x .= 'e';
}
?>
Suspicious Comparison
[Since 0.11.0] - [ -P Structures/SuspiciousComparison ] - [ Online docs ]
The comparison seems to be misplaced.
A comparison happens in the last argument, while the actual function expect another type : this may be the case of a badly placed parenthesis.
<?php
// trim expect a string, a boolean is given.
if (trim($str === '')){
}
// Just move the first closing parenthesis to give back its actual meaning
if (trim($str) === ''){
}
?>
Original idea by Vladimir Reznichenko.
Strings With Strange Space
[Since 0.11.0] - [ -P Type/StringWithStrangeSpace ] - [ Online docs ]
An invisible space may be mistaken for a normal space.
However, PHP does straight comparisons, and may fail at recognizing. This analysis reports when it finds such strange spaces inside strings.
PHP doesn't mistake space and tables for whitespace when tokenizing the code.
This analysis doesn't report Unicode Codepoint Notation : those are visible in the code.
<?php
// PHP 7 notation,
$a = \u{3000};
$b = ;
// Displays false
var_dump($a === $b);
?>
See also Unicode spaces and disallow irregular whitespace (no-irregular-whitespace)
No Empty Regex
[Since 0.11.1] - [ -P Structures/NoEmptyRegex ] - [ Online docs ]
PHP regex don't accept empty regex, nor regex with alphanumeric delimiter.
Most of those errors happen at execution time, when the regex is build dynamically, but still may end empty. At compile time, such error are made when the code is not tested before commit.
<?php
// No empty regex
preg_match('', $string, $r);
// Delimiter must be non-alphanumerical
preg_replace('1abc1', $string, $r);
// Delimiter must be non-alphanumerical
preg_replace('1'.$regex.'1', $string, $r);
?>
See also PCRE and Delimiters.
Alternative Syntax Consistence
[Since 0.11.2] - [ -P Structures/AlternativeConsistenceByFile ] - [ Online docs ]
PHP allows for two syntax : the alternative syntax, and the classic syntax.
The classic syntax is almost always used. When used, the alternative syntax is used in templates.
This analysis reports files that are using both syntax at the same time. This is confusing.
<?php
// Mixing both syntax is confusing.
foreach($array as $item) :
if ($item > 1) {
print $item elements\n;
} else {
print $item element\n;
}
endforeach;
?>
Randomly Sorted Arrays
[Since 0.11.2] - [ -P Arrays/RandomlySortedLiterals ] - [ Online docs ]
Those literal arrays are written in several places, but their items are in various orders.
This may reduce the reading and proofing of the arrays, and induce confusion. The random order may also be a residue of development : both arrays started with different values, but they grew overtime to handle the same items. The way they were written lead to the current order.
Unless order is important, it is recommended to always use the same order when defining literal arrays. This makes it easier to match different part of the code by recognizing one of its literal.
<?php
// an array
$set = [1,3,5,9,10];
function foo() {
// an array, with the same values but different order, in a different context
$list = [1,3,5,10,9,];
}
// an array, with the same order than the initial one
$inits = [1,3,5,9,10];
?>
ext/sphinx
[Since 0.11.3] - [ -P Extensions/Extsphinx ] - [ Online docs ]
Extension for the Sphinx search server.
This extension provides bindings for Sphinx search client library.
<?php
$s = new SphinxClient;
$s->setServer(localhost, 6712);
$s->setMatchMode(SPH_MATCH_ANY);
$s->setMaxQueryTime(3);
$result = $s->query(test);
var_dump($result);
?>
See also Sphinx Client and Sphinx Search
Try With Multiple Catch
[Since 0.11.3] - [ -P Php/TryMultipleCatch ] - [ Online docs ]
Try may be used with multiple catch clauses.
<?php
try {
OneCatch();
} catch (FirstException $e) {
}
try {
TwoCatches();
} catch (FirstException $e) {
} catch (SecondException $e) {
}
?>
See also and Exceptions
ext/grpc
[Since 0.11.3] - [ -P Extensions/Extgrpc ] - [ Online docs ]
Extension for GRPC : A high performance, open-source universal RPC framework.
<?php
//https://github.com/grpc/grpc/blob/master/examples/php/greeter_client.php
require dirname(__FILE__).'/vendor/autoload.php';
// The following includes are needed when using protobuf 3.1.0
// and will suppress warnings when using protobuf 3.2.0+
@include_once dirname(__FILE__).'/helloworld.pb.php';
@include_once dirname(__FILE__).'/helloworld_grpc_pb.php';
function greet($name)
{
$client = new Helloworld\GreeterClient('localhost:50051', [
'credentials' => Grpc\ChannelCredentials::createInsecure(),
]);
$request = new Helloworld\HelloRequest();
$request->setName($name);
list($reply, $status) = $client->SayHello($request)->wait();
$message = $reply->getMessage();
return $message;
}
$name = !empty($argv[1]) ? $argv[1] : 'world';
echo greet($name).\n;
?>
See also GRPC and GRPC on PECL
Only Variable Passed By Reference
[Since 0.11.3] - [ -P Functions/OnlyVariablePassedByReference ] - [ Online docs ]
When an argument is expected by reference, it is compulsory to provide a container. A container may be a variable, an array, a property or a static property.
This may be linted by PHP, when the function definition is in the same file as the function usage. This is silently linted if definition and usage are separated, if the call is dynamical or made as a method.
<?php
function foo(&$bar) { /**/ }
function &bar() { /**/ }
// This is not possible : `strtolower() <https://www.php.net/strtolower>`_ returns a value
foo(strtolower($string));
// This is valid : bar() returns a reference
foo(bar($string));
?>
This analysis currently covers functioncalls and static methodcalls, but omits methodcalls.
See also and Passing arguments by reference
No Return Used
[Since 0.11.3] - [ -P Functions/NoReturnUsed ] - [ Online docs ]
The return value of the following methods are never used. The return argument may be dropped from the code, as it is dead code.
This analysis supports functions and static methods, when a definition may be found. It doesn't support method calls.
<?php
function foo($a = 1) { return 1; }
foo();
foo();
foo();
foo();
foo();
foo();
// This function doesn't return anything.
function foo2() { }
// The following function are used in an expression, thus the return is important
function foo3() { return 1;}
function foo4() { return 1;}
function foo5() { return 1;}
foo3() + 1;
$a = foo4();
foo(foo5());
?>
Use Browscap
[Since 0.11.4] - [ -P Php/UseBrowscap ] - [ Online docs ]
Browscap is a browser database, accessible via get_browser().
Browscap is the 'Browser Capabilities Project'.
<?php
echo $_SERVER['HTTP_USER_AGENT'] . \n\n;
$browser = get_browser(null, true);
print_r($browser);
?>
See also and browscap
Use Debug
[Since 0.11.4] - [ -P Structures/UseDebug ] - [ Online docs ]
The code source includes calls to debug functions.
The following debug functions and libraries are reported :
- Aronduby Dump
- Cakephp Debug Toolbar
- Kint
- Krumo
- Nette tracy
- php-debugbar
- PHP native functions : print_r(), var_dump(), debug_backtrace(), debug_print_backtrace(), debug_zval_dump()
- Symfony debug
- Wordpress debug
- Xdebug
- Zend debug
<?php
// Example with Zend Debug
Zend\Debug\Debug::dump($var, $label = null, $echo = true);
?>
No Reference On Left Side
[Since 0.11.5] - [ -P Structures/NoReferenceOnLeft ] - [ Online docs ]
Do not use references as the right element in an assignation.
<?php
$b = 2;
$c = 3;
$a = &$b + $c;
// $a === 2 === $b;
$a = $b + $c;
// $a === 5
?>
This is the case for most situations : addition, multiplication, bitshift, logical, power, concatenation.
Note that PHP won't compile the code if the operator is a short operator (+=, .=, etc.), nor if the & is on the right side of the operator.
See also References Explained and Operator Precedence
Implemented Methods Must Be Public
[Since 0.11.5] - [ -P Classes/ImplementedMethodsArePublic ] - [ Online docs ]
Class methods that are defined in an interface must be public. They cannot be either private, nor protected.
<?php
interface i {
function foo();
}
class X {
// This method is defined in the interface : it must be public
protected function foo() {}
// other methods may be private
private function bar() {}
}
?>
This error is not reported by lint, and is reported at execution time.
See also Interfaces and Interfaces - the next level of abstraction
PSR-16 Usage
[Since 0.11.6] - [ -P Psr/Psr16Usage ] - [ Online docs ]
PSR-16 describes a simple yet extensible interface for a cache item and a cache driver. It is supported by an set of interfaces, that one may use in the code.
<?php
namespace My\SimpleCache;
// MyCache implements the PSR-16 Simple cache.
// MyCache is more of a black hole than a real cache.
class MyCache implements Psr\SimpleCache\CacheInterface {
public function get($key, $default = null) {}
public function set($key, $value, $ttl = null) {}
public function delete($key) {}
public function clear() {}
public function getMultiple($keys, $default = null) {}
public function setMultiple($values, $ttl = null) {}
public function deleteMultiple($keys) {}
public function has($key) {}
}
?>
See also and PSR-16 : Common Interface for Caching Libraries
PSR-7 Usage
[Since 0.11.6] - [ -P Psr/Psr7Usage ] - [ Online docs ]
PSR-7 describes common interfaces for representing HTTP messages as described in RFC 7230 and RFC 7231, and URI for use with HTTP messages as described in RFC 3986.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyServerRequest implements the PSR-7 ServerRequestInterface.
// MyServerRequest is more of a black hole than a real Server.
class MyServerRequest extends \Psr\Http\Message\ServerRequestInterface {
public function getServerParams() {}
public function getCookieParams() {}
public function withCookieParams(array $cookies) {}
public function getQueryParams() {}
public function withQueryParams(array $query) {}
public function getUploadedFiles() {}
public function withUploadedFiles(array $uploadedFiles) {}
public function getParsedBody() {}
public function withParsedBody($data) {}
public function getAttributes() {}
public function getAttribute($name, $default = null) {}
public function withAttribute($name, $value) {}
public function withoutAttribute($name) {}
}
?>
See also and PSR-7 : HTTP message interfaces
PSR-6 Usage
[Since 0.11.6] - [ -P Psr/Psr6Usage ] - [ Online docs ]
PSR-6 is the cache standard for PHP.
The goal of PSR-6 is to allow developers to create cache-aware libraries that can be integrated into existing frameworks and systems without the need for custom development.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyCacheItem implements the PSR-7 CacheItemInterface.
// This MyCacheItem is more of a black hole than a real CacheItem.
class MyCacheItem implements \Psr\Cache\CacheItemInterface {
public function getKey() {}
public function get() {}
public function isHit() {}
public function set($value) {}
public function expiresAt($expiration) {}
public function expiresAfter($time) {}
}
?>
See also and PSR-6 : Caching
PSR-3 Usage
[Since 0.11.6] - [ -P Psr/Psr3Usage ] - [ Online docs ]
PSR-3 describes a common interface for logging libraries.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyLog implements the PSR-3 LoggerInterface.
// MyLog is more of a black hole than a real Log.
namespace ;
class MyLog implements \Psr\Log\LoggerInterface {
public function emergency($message, array $context = array()) {}
public function alert($message, array $context = array()) {}
public function critical($message, array $context = array()) {}
public function error($message, array $context = array()) {}
public function warning($message, array $context = array()) {}
public function notice($message, array $context = array()) {}
public function info($message, array $context = array()) {}
public function debug($message, array $context = array()) {}
public function log($level, $message, array $context = array()) {}
}
?>
See also and PSR-3 : Logger Interface
PSR-11 Usage
[Since 0.11.5] - [ -P Psr/Psr11Usage ] - [ Online docs ]
PSR-11 describes a common interface for dependency injection containers.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyContainerInterface implements the PSR-7 ServerRequestInterface.
// MyContainerInterface is more of a black hole than a real Container.
class MyContainerInterface implements \Psr\Container\ContainerInterface {
public function get($id) {}
public function has($id) {}
}
?>
See also and PSR-11 : Dependency injection container
PSR-13 Usage
[Since 0.11.6] - [ -P Psr/Psr13Usage ] - [ Online docs ]
PSR-13 describes a common interface for dependency injection containers.
It is supported by an set of interfaces, that one may use in the code.
<?php
namespace MyNamespace;
// MyLink implements the PSR-13 LinkInterface.
// MyLink is more of a black hole than a real Container.
class MyLink implements LinkInterface {
public function getHref() {}
public function isTemplated() {}
public function getRels() {}
public function getAttributes() {}
}
?>
See also and PSR-13 : Link definition interface
Mixed Concat And Interpolation
[Since 0.11.5] - [ -P Structures/MixedConcatInterpolation ] - [ Online docs ]
Mixed usage of concatenation and string interpolation is error prone. It is harder to read, and leads to overlooking the concatenation or the interpolation.
<?php
// Concatenation string
$a = $b . 'c' . $d;
// Interpolation strings
$a = {$b}c{$d}; // regular form
$a = {$b}c$d; // irregular form
// Mixed Concatenation and Interpolation string
$a = {$b}c . $d;
$a = $b . c$d;
$a = $b . c{$d};
// Mixed Concatenation and Interpolation string with constant
$a = {$b}c . CONSTANT;
?>
Fixing this issue has no impact on the output. It makes code less error prone.
There are some situations where using concatenation are compulsory : when using a constant, calling a function, running a complex expression or make use of the escape sequence. You may also consider pushing the storing of such expression in a local variable.
ext/stats
[Since 0.11.5] - [ -P Extensions/Extstats ] - [ Online docs ]
Statistics extension.
This extension contains few dozens of functions useful for statistical computations. It is a wrapper around 2 scientific libraries, namely DCDFLIB (Library of C routines for Cumulative Distributions Functions, Inverses, and Other parameters) by B. Brown & J. Lavato and RANDLIB by Barry Brown, James Lavato & Kathy Russell.
<?php
$x = [ 15, 16, 8, 6, 15, 12, 12, 18, 12, 20, 12, 14, ];
$y = [ 17.24, 15, 14.91, 4.5, 18, 6.29, 19.23, 18.69, 7.21, 42.06, 7.5, 8,];
sprintf(%2.9f, stats_covariance($a_1, $a_2));
?>
See also Statistics and ext/stats
Too Many Injections
[Since 0.11.6] - [ -P Classes/TooManyInjections ] - [ Online docs ]
When a class is constructed with more than four dependencies, it should be split into smaller classes.
<?php
// This class relies on 5 other instances.
// It is probably doing too much.
class Foo {
public function __construct(
A $a,
B $b,
C $c,
D $d
E $e ) {
$this->a = $a;
$this->b = $b;
$this->d = $d;
$this->d = $d;
$this->e = $e;
}
}
?>
See also and Dependency Injection Smells
Dependency Injection
[Since 0.11.6] - [ -P Patterns/DependencyInjection ] - [ Online docs ]
A dependency injection is a typehinted argument, that is stored in a property by the constructor.
<?php
// Classic dependency injection
class foo {
private $bar;
public function __construct(Bar $bar) {
$this->bar = $bar;
}
public function doSomething($args) {
return $this->bar->barbar($args);
}
}
// Without typehint, this is not a dependency injection
class foo {
private $bar;
public function __construct($bar) {
$this->bar = $bar;
}
}
?>
See also and Understanding Dependency Injection
Courier Anti-Pattern
[Since 0.11.6] - [ -P Patterns/CourrierAntiPattern ] - [ Online docs ]
The courier anti-pattern is the storage of a dependency by a class, in order to create an instance that requires this dependency.
The class itself doesn't actually need this dependency, but has a dependency to a class that requires it.
<?php
// The foo class requires bar
class Foo {
public function __construct(Bar $b) {
}
}
// Class A doesn't depends on Bar, but depends on Foo
// Class A never uses Bar, but only uses Foo.
class A {
private $courier;
public function __construct(Bar $courier) {
$this->courier = $courier;
}
public function Afoo() {
$b = new Foo($this->courier);
}
}
?>
The alternative here is to inject Foo instead of Bar.
See also and Courier Anti-pattern
ext/gender
[Since 0.11.6] - [ -P Extensions/Extgender ] - [ Online docs ]
Gender extension.
The Gender PHP extension is a port of the gender.c program originally written by Joerg Michael. Its main purpose is to find out the gender of firstnames, based on a database of over 40000 firstnames from 54 countries.
<?php
namespace Gender;
$gender = new Gender;
$name = 'Milene';
$country = Gender::FRANCE;
$result = $gender->get($name, $country);
$data = $gender->country($country);
switch($result) {
case Gender::IS_FEMALE:
printf('The name %s is female in %s\n', $name, $data['country']);
break;
case Gender::IS_MOSTLY_FEMALE:
printf('The name %s is mostly female in %s\n', $name, $data['country']);
break;
case Gender::IS_MALE:
printf('The name %s is male in %s\n', $name, $data['country']);
break;
case Gender::IS_MOSTLY_MALE:
printf('The name %s is mostly male in %s\n', $name, $data['country']);
break;
case Gender::IS_UNISEX_NAME:
printf('The name %s is unisex in %s\n', $name, $data['country']);
break;
case Gender::IS_A_COUPLE:
printf('The name %s is both male and female in %s\n', $name, $data['country']);
break;
case Gender::NAME_NOT_FOUND:
printf('The name %s was not found for %s\n', $name, $data['country']);
break;
case Gender::ERROR_IN_NAME:
echo 'There is an error in the given name!'.PHP_EOL;
break;
default:
echo 'An error occurred!'.PHP_EOL;
break;
}
?>
See also ext/gender manual and genderReader
ext/judy
[Since 0.11.6] - [ -P Extensions/Extjudy ] - [ Online docs ]
The Judy extension.
PHP Judy is a PECL extension for the Judy C library implementing dynamic sparse arrays.
<?php
$judy = new Judy(Judy::BITSET);
if ($judy->getType() === judy_type($judy) &&
$judy->getType() === Judy::BITSET) {
echo 'Judy BITSET type OK'.PHP_EOL;
} else {
echo 'Judy BITSET type check fail'.PHP_EOL;
}
unset($judy);
?>
See also and php-judy
Could Make A Function
[Since 0.11.6] - [ -P Functions/CouldCentralize ] - [ Online docs ]
When a function is called across the code with the same arguments often enough, it should be turned into a local API.
This approach is similar to turning literals into constants : it centralize the value, it helps refactoring by updating it. It also makes the code more readable. Moreover, it often highlight common grounds between remote code locations.
The analysis looks for functions calls, and checks the arguments. When the calls occurs more than 4 times, it is reported.
<?php
// str_replace is used to clean '&' from strings.
// It should be upgraded to a central function
function foo($arg ) {
$arg = str_replace('&', '', $arg);
// do something with $arg
}
class y {
function bar($database ) {
$value = $database->queryName();
$value = str_replace('&', '', $value);
// $value = removeAmpersand($value);
// do something with $arg2
}
}
// helper function
function removeAmpersand($string) {
return str_replace('&', '', $string);
}
?>
See also and Don't repeat yourself (DRY)
Forgotten Interface
[Since 0.11.7] - [ -P Interfaces/CouldUseInterface ] - [ Online docs ]
The following classes have been found implementing an interface's methods, though it doesn't explicitly implements this interface. This may have been forgotten.
<?php
interface i {
function i();
}
// i is not implemented and declared
class foo {
function i() {}
function j() {}
}
// i is implemented and declared
class foo implements i {
function i() {}
function j() {}
}
?>
See also and Traits/CouldUseTrait
Yii usage
[Since 0.11.8] - [ -P Vendors/Yii ] - [ Online docs ]
This analysis reports usage of the Yii 2 framework.
This analysis targets Yii 2, not Yii 1.
<?php
// A Yii controller
class SiteController extends \Yii\Web\Controller
{
public function actionIndex()
{
// ...
}
public function actionContact()
{
// ...
}
}
?>
See also and Yii
Codeigniter usage
[Since 0.11.8] - [ -P Vendors/Codeigniter ] - [ Online docs ]
This analysis reports usage of the Codeigniter 4 framework.
Note : Code igniter 3 and older are not reported.
<?php
// A code igniter controller
class Blog extends \App\Controllers\Home {
public function index()
{
echo 'Hello World!';
}
}
?>
See also and Codeigniter
Laravel usage
[Since 0.11.8] - [ -P Vendors/Laravel ] - [ Online docs ]
This analysis reports usage of the Laravel framework.
<?php
namespace App\Http\Controllers;
use App\User;
use App\Http\Controllers\Controller;
class UserController extends Controller
{
/**
* Show the profile for the given user.
*
* @param int $id
* @return Response
*/
public function show($id)
{
return view('user.profile', ['user' => User::findOrFail($id)]);
}
}
?>
See also and Laravel
Symfony usage
[Since 0.11.8] - [ -P Vendors/Symfony ] - [ Online docs ]
This analysis reports usage of the Symfony framework.
<?php
// src/AppBundle/Controller/LuckyController.php
namespace AppBundle\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Component\HttpFoundation\Response;
class LuckyController
{
/**
* @Route(/lucky/number)
*/
public function numberAction()
{
$number = mt_rand(0, 100);
return new Response(
'<html><body>Lucky number: '.$number.'</body></html>'
);
}
}
?>
See also and Symfony
Wordpress usage
[Since 0.11.8] - [ -P Vendors/Wordpress ] - [ Online docs ]
This analysis reports usage of the Wordpress platform.
The current supported version is Wordpress 5.8.
<?php
//Usage of the WP_http class from Wordpress
$rags = array(
'x' => '1',
'y' => '2'
);
$url = 'http://www.example.com/';
$request = new WP_Http();
$result = $request->request( $url, array( 'method' => 'POST', 'body' => $body) );
?>
See also and Wordpress
Ez cms usage
[Since 0.11.8] - [ -P Vendors/Ez ] - [ Online docs ]
This analysis reports usage of the Ez CMS.
<?php
namespace My\Bundle\With\Controller;
use eZ\Bundle\EzPublishCoreBundle\Controller;
use Symfony\Component\HttpFoundation\Request;
class DemoController extends Controller {
public function demoCreateContentAction(Request $request) {
//
}
}
?>
See also and Ez
Joomla usage
[Since 0.11.8] - [ -P Vendors/Joomla ] - [ Online docs ]
This analysis reports usage of the Joomla CMS.
<?php
// no direct access
defined('_JEXEC') or die('Restricted access');
jimport('joomla.application.component.controller');
JLoader::import('KBIntegrator', JPATH_PLUGINS . DS . 'kbi');
class MyController extends JController {
function display($message) {
echo $message;
}
}
?>
See also and Joomla
Non Breakable Space In Names
[Since 0.12.0] - [ -P Structures/NonBreakableSpaceInNames ] - [ Online docs ]
PHP allows non-breakable spaces in structures names, such as class, interfaces, traits, and variables.
This may be a nice trick to make names more readable outside code context, like long-named methods for tests.
<?php
class class with non breakable spaces {}
class ClassWithoutNonBreakableSpaces {}
?>
Original post by Matthieu Napoli .
.
See also Using non-breakable spaces in test method names and PHP Variable Names
Multiple Functions Declarations
[Since 0.12.0] - [ -P Functions/MultipleDeclarations ] - [ Online docs ]
Some functions are declared multiple times in the code.
PHP accepts multiple definitions for the same functions, as long as they are not in the same file (linting error), or not included simultaneously during the execution.
This creates to several situations in which the same functions are defined multiple times : the function may be compatible with various PHP version, but their implementation may not. Or the function is part of a larger library, and sometimes only need without the rest of the library.
It is recommended to avoid having several functions with the same name in one repository. Turn those functions into methods and load them when needed.
<?php
namespace a {
function foo() {}
}
// Other file
namespace a {
function foo() {}
function bar() {}
}
?>
Avoid Optional Properties
[Since 0.12.0] - [ -P Classes/AvoidOptionalProperties ] - [ Online docs ]
Avoid optional properties, to prevent littering the code with existence checks.
When a property has to be checked once for existence, it is safer to check it each time. This leads to a decrease in readability and a lot of checks added to the code.
Either make sure the property is set with an actual object rather than with null, or use a null object. A null object offers the same interface than the expected object, but does nothing. It allows calling its methods, without running into a Fatal error, nor testing it.
<?php
// Example is courtesy 'The Coding Machine' : it has been adapted from its original form. See link below.
class MyMailer {
private $logger;
public function __construct(LoggerInterface $logger = null) {
$this->logger = $logger;
}
private function sendMail(Mail $mail) {
// Since $this->logger may be null, it must be tested anytime it is used.
if ($this->logger) {
$this->logger->info('Mail successfully sent.');
}
}
}
?>
See also Avoid optional services as much as possible, The Null Object Pattern – Polymorphism in Domain Models and Practical PHP Refactoring: Introduce Null Object
Swoole
[Since 0.12.0] - [ -P Extensions/Extswoole ] - [ Online docs ]
Swoole : Production-Grade Async programming Framework for PHP.
Swoole is an event-driven asynchronous & concurrent networking communication framework with high performance written only in C for PHP.
<?php
for($i = 0; $i < 100; $i++) {
Swoole\Coroutine::create(function() use ($i) {
$redis = new Swoole\Coroutine\Redis();
$res = $redis->connect('127.0.0.1', 6379);
$ret = $redis->incr('coroutine');
$redis->close();
if ($i == 50) {
Swoole\Coroutine::create(function() use ($i) {
$redis = new Swoole\Coroutine\Redis();
$res = $redis->connect('127.0.0.1', 6379);
$ret = $redis->set('coroutine_i', 50);
$redis->close();
});
}
});
}
?>
See also Swoole and Swoole src
Manipulates NaN
[Since 0.10.6] - [ -P Php/IsNAN ] - [ Online docs ]
This code handles Not-a-Number situations. Not-a-Number , also called NaN , happens when a calculation can't return an actual float.
<?php
// acos returns a float, unless it is not possible.
$a = acos(8);
var_dump(is_nan($a));
?>
See also and Floats
Manipulates INF
[Since 0.10.6] - [ -P Php/IsINF ] - [ Online docs ]
This code handles INF situations. INF represents the infinity, when used in a float context. It happens when a calculation returns a number that is much larger than the maximum allowed float (not integer), or a number that is not a Division by 0.
<?php
// pow returns INF, as it is equivalent to 1 / 0 ^ 2
$a = pow(0,-2); //
// exp returns an actual value, but won't be able to represent it as a float
$a = exp(PHP_INT_MAX);
// 0 ^ -1 is like 1 / 0 but returns INF.
$a = pow(0, -1);
var_dump(is_infinite($a));
// This yields a Division by zero exception
$a = 1 / 0;
?>
See also and Math predefined constants
Const Or Define
[Since 0.12.1] - [ -P Structures/ConstDefineFavorite ] - [ Online docs ]
const and define()
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
They are almost interchangeable, though not totally : define()
<?php
// be consistent
const A1 = 1 ;
const A2 = 2 ;
const A3 = 3 ;
const A4 = 4 ;
const A5 = 5 ;
const A6 = 6 ;
const A7 = 7 ;
const A8 = 8 ;
const A9 = 9 ;
const A10 = 10;
const A11 = 11;
define('A12', 12); // Be consistent, always use the same.
?>
See also define and const
strict_types Preference
[Since 0.12.2] - [ -P Php/DeclareStrict ] - [ Online docs ]
strict_types is a PHP mode where typehint are enforced strictly or weakly. By default, it is weak typing, allowing backward compatibility with previous versions.
This analysis reports if strict_types are used systematically or not. strict_types affects the calling file, not the definition file.
<?php
// define strict_types
declare(strict_types = 1);
foo(1);
?>
See also and Strict typing
Declare strict_types Usage
[Since 0.12.1] - [ -P Php/DeclareStrictType ] - [ Online docs ]
Usage of strict_types . By default, PHP attempts to change the original type to match the type specified by the type-declaration. With an explicit strict_types declaration, PHP ensures that the incoming argument has the exact type.
strict_types were introduced in PHP 7.0.
<?php
// Setting strict_types;
declare(strict_types = 1);
function foo(int $i) {
echo $i;
}
// Always valid : displays 1
foo(1);
// with strict types, this emits an error
// without strict types, this displays 1
foo(1.7);
?>
See also and declare
Encoding Usage
[Since 0.12.1] - [ -P Php/DeclareEncoding ] - [ Online docs ]
Usage of declare(encoding = );.
<?php
// Setting encoding for the file;
declare(encoding = 'UTF-8');
?>
See also and declare
Ticks Usage
[Since 0.12.1] - [ -P Php/DeclareTicks ] - [ Online docs ]
Usage of declare() with ticks . When ticks are declared, a related handler must be registered with register_tick_function().
See also and declare
Mismatched Ternary Alternatives
[Since 0.12.1] - [ -P Structures/MismatchedTernary ] - [ Online docs ]
A ternary operator should yield the same type on both branches.
Ternary operator applies a condition, and yield two different results. Those results will then be processed by code that expects the same types. It is recommended to match the types on both branches of the ternary operator.
<?php
// $object may end up in a very unstable state
$object = ($type == 'Type') ? new $type() : null;
//same result are provided by both alternative, though process is very different
$result = ($type == 'Addition') ? $a + $b : $a * $b;
//Currently, this is omitted
$a = 1;
$result = empty($condition) ? $a : 'default value';
$result = empty($condition) ? $a : getDefaultValue();
?>
Mismatched Default Arguments
[Since 0.12.3] - [ -P Functions/MismatchedDefaultArguments ] - [ Online docs ]
Arguments are relayed from one method to the other, and the arguments have different default values.
Although it is possible to have different default values, it is worth checking why this is actually the case.
<?php
function foo($a = null, $b = array() ) {
// foo method calls directly bar.
// When argument are provided, it's OK
// When argument are omited, the default value is not the same as the next method
bar($a, $b);
}
function bar($c = 1, $d = array() ) {
}
?>
This analysis reports the original arguments. Starting from it, follow the usage of the argument in its method, and find calls to other methods.
This analysis omits reporting argument when one of them does not have a default value.
Mismatched Typehint
[Since 0.12.3] - [ -P Functions/MismatchedTypehint ] - [ Online docs ]
Relayed arguments don't have the same typehint.
Typehint acts as a filter method. When an object is checked with a first class, and then checked again with a second distinct class, the whole process is always false : $a can't be of two different classes at the same time.
<?php
// Foo() calls bar()
function foo(A $a, B $b) {
bar($a, $b);
}
// $a is of A typehint in both methods, but
// $b is of B then BB typehing
function bar(A $a, BB $b) {
}
?>
Note : This analysis currently doesn't check generalisation of classes : for example, when B is a child of BB, it is still reported as a mismatch.
Scalar Or Object Property
[Since 0.12.3] - [ -P Classes/ScalarOrObjectProperty ] - [ Online docs ]
Property shouldn't use both object and scalar syntaxes. When a property may be an object, it is recommended to implement the Null Object pattern : instead of checking if the property is scalar, make it always object.
<?php
class x {
public $display = 'echo';
function foo($string) {
if (is_string($this->display)) {
echo $this->string;
} elseif ($this->display instanceof myDisplayInterface) {
$display->display();
} else {
print Error when displaying\n;
}
}
}
interface myDisplayInterface {
public function display($string); // does the display in its own way
}
class nullDisplay implements myDisplayInterface {
// implements myDisplayInterface but does nothing
public function display($string) {}
}
class x2 {
public $display = null;
public function __construct() {
$this->display = new nullDisplay();
}
function foo($string) {
// Keep the check, as $display is public, and may get wrong values
if ($this->display instanceof myDisplayInterface) {
$display->display();
} else {
print Error when displaying\n;
}
}
}
// Simple class for echo
class echoDisplay implements myDisplayInterface {
// implements myDisplayInterface but does nothing
public function display($string) {
echo $string;
}
}
?>
See also Null Object Pattern and The Null Object Pattern
Assign With And Precedence
[Since 0.12.4] - [ -P Php/AssignAnd ] - [ Online docs ]
The lettered logical operators yield to assignation. It may collect less information than expected.
It is recommended to use the &&, ^ and || operators, instead of and, or and xor, to prevent confusion.
<?php
// The expected behavior is
// The following are equivalent
$a = $b && $c;
$a = ($b && $c);
// The unexpected behavior is
// The following are equivalent
$a = $b and $c;
($a = $b) and $c;
?>
See also and Operator Precedence
No Magic Method With Array
[Since 0.12.4] - [ -P Classes/NoMagicWithArray ] - [ Online docs ]
Magic method __set() doesn't work for array syntax.
When overloading properties, they can only be used for scalar values, excluding arrays. Under the hood, PHP uses __get() to reach for the name of the property, and doesn't recognize the following index as an array. It yields an error : Indirect modification of overloaded property.
<?php
class c {
private $a;
private $o = array();
function __get($name) {
return $this->o[$name];
}
function foo() {
// property b doesn't exists
$this->b['a'] = 3;
print_r($this);
}
// This method has no impact on the issue
function __set($name, $value) {
$this->o[$name] = $value;
}
}
$c = new c();
$c->foo();
?>
It is possible to use the array syntax with a magic property : by making the __get returns an array, the syntax will actually extract the expected item in the array.
This is not reported by linting.
In this analysis, only properties that are found to be magic are reported. For example, using the b property outside the class scope is not reported, as it would yield too many false-positives.
See also Overload.
ext/xattr
[Since 0.12.4] - [ -P Extensions/Extxattr ] - [ Online docs ]
Extensions xattr.
The xattr extension allows for the manipulation of extended attributes on a filesystem.
<?php
$file = 'my_favourite_song.wav';
xattr_set($file, 'Artist', 'Someone');
xattr_set($file, 'My ranking', 'Good');
xattr_set($file, 'Listen count', '34');
/* ... other code ... */
printf('You\'ve played this song %d times', xattr_get($file, 'Listen count'));
?>
See also xattr and Extended attributres
Logical To in_array
[Since 0.12.5] - [ -P Performances/LogicalToInArray ] - [ Online docs ]
Multiple exclusive comparisons with or may be replaced by faster alternative.
+ isset() and an array which keys are the target comparisons
+ array_key_exists() and an array which keys are the target comparisons
+ strpos() call, with all the target values merged into a string
+ str_contains() call, with all the target values merged into a string
+ switch() call, with each case being an assignation
+ match() call
+ in_array() call, with each values in an array
While each alternative has its performance gain, they make the code more readable by bringing the alternative values into one simple list.
As little as three or comparisons are slower than using an alternative. The more calls, the slower is as string of or . Also, the further the target value is in the or list, the slower it is to find it. Although, it is not easy to control that value.
This analysis also reports in_array() calls with arrays of a single element : those should be turned into a or call, or have more values in the array, or have the array published as a constant.
<?php
$targetValues = array('a', 'b', 'c', 'd');
$needle = 'd'; // for example
// isset() & `array_key_exists() <https://www.php.net/array_key_exists>`_
$targets = array_flip($targetValues); // This might be a slow operation
isset($targs[$a]);
array_key_exists($a, $targs);
// `strpos() <https://www.php.net/strpos>`_ & str_contains
$targets = implode('', $targeValues);
strpos($targets, $needle) !== 0
str_contains($targets, $needle) !== 0
// switch()
switch($needle) {
case 'a': // Lots of typing to do
case 'b':
case 'c':
case 'd':
$result = true;
break;
default:
$result = false;
break;
}
// match()
// surprisingly, slitghly slower than switch()
$result = match($needle) {
'a', 'b', 'c', 'd' => true,
default => false
};
// `in_array() <https://www.php.net/in_array>`_
// Set the list of alternative in a variable, property or constant.
$result = in_array($a, $valid_values, true); // use third argument when you can
// slowest and hard to read
$result = $a == 'a' || $a == 'b' || $a == 'c' || $a == 'd');
?>
This is a micro-optimisation : speed gain is low, and marginal. Code centralisation is a more significant advantage.
Thanks to Frederic Bouchery for extending the alternatives of that analysis.
See also in_array()
ext/rdkafka
[Since 0.12.8] - [ -P Extensions/Extrdkafka ] - [ Online docs ]
Extension for RDkafka.
PHP-rdkafka is a thin librdkafka binding providing a working PHP 5 / PHP 7 Kafka 0.8 / 0.9 / 0.10 client.
<?php
$rk = new RdKafka\Producer();
$rk->setLogLevel(LOG_DEBUG);
$rk->addBrokers(10.0.0.1,10.0.0.2);
?>
See also Kafka client for PHP and librdkafka
ext/fam
[Since 0.12.8] - [ -P Extensions/Extfam ] - [ Online docs ]
File Alteration Monitor extension.
FAM monitors files and directories, notifying interested applications of changes.
ext/FAM is not available for Windows
<?php
$fam = fam_open('myApplication');
fam_monitor_directory($fam, '/tmp');
fam_close($fam);
?>
See also and File Alteration Monitor
Pathinfo() Returns May Vary
[Since 0.12.11] - [ -P Php/PathinfoReturns ] - [ Online docs ]
pathinfo() function returns an array whose content may vary. It is recommended to collect the values after check, rather than directly.
<?php
$file = '/a/b/.c';
//$extension may be missing, leading to empty $filename and filename in $extension
list( $dirname, $basename, $extension, $filename ) = array_values( pathinfo($file) );
//Use PHP 7.1 list() syntax to assign correctly the values, and skip `array_values() <https://www.php.net/array_values>`_
//This emits a warning in case of missing index
['dirname' => $dirname,
'basename' => $basename,
'extension' => $extension,
'filename' => $filename ] = pathinfo($file);
//This works without warning
$details = pathinfo($file);
$dirname = $details['dirname'] ?? getpwd();
$basename = $details['basename'] ?? '';
$extension = $details['extension'] ?? '';
$filename = $details['filename'] ?? '';
?>
The same applies to parse_url(), which returns an array with various index.
ext/parle
[Since 0.12.12] - [ -P Extensions/Extparle ] - [ Online docs ]
Extension Parser and Lexer.
The parle extension provides lexing and parsing facilities. The implementation is based on » Ben Hanson's libraries and requires a » C++14 capable compiler.
<?php
use Parle\{Token, Lexer, LexerException};
/* name => id */
$token = array(
'EOI' => 0,
'COMMA' => 1,
'CRLF' => 2,
'DECIMAL' => 3,
);
/* id => name */
$token_rev = array_flip($token);
$lex = new Lexer;
$lex->push("[\x2c]", $token['COMMA']);
$lex->push("[\r][\n]", $token['CRLF']);
$lex->push("[\d]+", $token['DECIMAL']);
$lex->build();
$in = 0,1,2\r\n3,42,5\r\n6,77,8\r\n;
$lex->consume($in);
do {
$lex->advance();
$tok = $lex->getToken();
if (Token::UNKNOWN == $tok->id) {
throw new LexerException('Unknown token "'.$tok->value.'" at offset '.$tok->offset.'.');
}
echo 'TOKEN: ', $token_rev[$tok->id], PHP_EOL;
} while (Token::EOI != $tok->id);
?>
See also and Parsing and Lexing
Regex Inventory
[Since 0.12.14] - [ -P Type/Regex ] - [ Online docs ]
All regular expressions used in the code. PHP relies on the PCRE extension to process them, with the functions preg_match(), preg_replace(), etc.
<?php
// PCRE regex used with preg_match
preg_match('/[abc]+/', $string);
// Mbstring regex, in the arabic range
if(mb_ereg('[\x{0600}-\x{06FF}]', $text))
?>
mbstring regular expressions are also collected. POSIX regex are not listed : they were deprecated in PHP 7.0.
See also preg_match(), `ext/mbstring
Multiple Type Variable
[Since 0.12.15] - [ -P Structures/MultipleTypeVariable ] - [ Online docs ]
Avoid using the same variable with different types of data.
It is recommended to use different names for differently typed data, while processing them. This prevents errors where one believe the variable holds the former type, while it has already been cast to the later.
Incrementing variables, with math operations or concatenation, is OK : the content changes, but not the type. And casting the variable without storing it in itself is OK.
<?php
// $x is an array
$x = range('a', 'z');
// $x is now a string
$x = join('', $x);
$c = count($x); // $x is not an array anymore
// $letters is an array
$letters = range('a', 'z');
// $alphabet is a string
$alphabet = join('', $letters);
// Here, $letters is cast by PHP, but the variable is changed.
if ($letters) {
$count = count($letters); // $letters is still an array
}
?>
Is Actually Zero
[Since 0.12.15] - [ -P Structures/IsZero ] - [ Online docs ]
This addition actually may be simplified because one term is actually negated by another.
This kind of error happens when the expression is very large : the more terms are included, the more chances are that some auto-annihilation happens.
This error may also be a simple typo : for example, calculating the difference between two consecutive terms.
<?php
// This is quite obvious
$a = 2 - 2;
// This is obvious too. This may be a typo-ed difference between two consecutive terms.
// Could have been $c = $fx[3][4] - $fx[3][3] or $c = $fx[3][5] - $fx[3][4];
$c = $fx[3][4] - $fx[3][4];
// This is less obvious
$a = $b[3] - $c + $d->foo(1,2,3) + $c + $b[3];
?>
Unconditional Break In Loop
[Since 0.12.16] - [ -P Structures/UnconditionLoopBreak ] - [ Online docs ]
An unconditional break in a loop creates dead code. Since the break is directly in the body of the loop, it is always executed, creating a strange loop that can only run once.
Here, break may also be a return, a goto or a continue. They all branch out of the loop. Such statement are valid, but should be moderated with a condition.
<?php
// return in loop should be in
function summAll($array) {
$sum = 0;
foreach($array as $a) {
// Stop at the first error
if (is_string($a)) {
return $sum;
}
$sum += $a;
}
return $sum;
}
// foreach loop used to collect first element in array
function getFirst($array) {
foreach($array as $a) {
return $a;
}
}
?>
Too Complex Expression
[Since 0.12.16] - [ -P Structures/ComplexExpression ] - [ Online docs ]
Long expressions should be broken in small chunks, to limit complexity.
Really long expressions tends to be error prone : either by typo, or by missing details. They are even harder to review, once the initially build of the expression is gone.
As a general rule, it is recommended to keep expressions short. The analysis include any expression that is more than 15 tokens large : variable and operators counts as one, properties, arrays count as two. Parenthesis are also counted.
PHP has no specific limit to expression size, so long expression are legal and valid. It is possible that the business logic requires a complex equation.
<?php
// Why not calculate wordwrap size separatedly ?
$a = explode("\n", wordwrap($this->message, floor($this->width / imagefontwidth($this->fontsize)), "\n"));
// Longer but easier to read
$width = floor($this->width / imagefontwidth($this->fontsize)), "\n");
$a = explode("\n", wordwrap($this->message, $width);
// Here, some string building, including error management with @, is making the data quite complex.
fwrite($fp, 'HEAD ' . @$url['path'] . @$url['query'] . ' HTTP/1.0' . "\r\n" . 'Host: ' . @$url['host'] . "\r\n\r\n")
// Better validation of data.
$http_header = 'HEAD ';
if (isset($url['path'])) {
$http_header .= $url['path'];
}
if (isset($url['query'])) {
$http_header .= $url['query'];
}
$http_header .= "\r\n";
if (isset($url['host'])) {
$http_header .= 'Host: ' . $url['host'] . "\r\n\r\n";
}
fwrite($fp, $http_header);
?>
Could Be Else
[Since 1.0.1] - [ -P Structures/CouldBeElse ] - [ Online docs ]
Merge opposite conditions into one if/then structure.
When two if/then structures follow each other, using a condition and its opposite, they may be merged into one.
<?php
// Short version
if ($a == 1) {
$b = 2;
} else {
$b = 1;
}
// Long version
if ($a == 1) {
$b = 2;
}
if ($a != 1) {
$b = 3;
}
?>
Next Month Trap
[Since 1.0.1] - [ -P Structures/NextMonthTrap ] - [ Online docs ]
Avoid using +1 month with strtotime().
strtotime() calculates the next month by incrementing the month number. For day number that do not exist from one month to the next, strtotime() fixes them by setting them in the next-next month.
This happens to January, March, May, July, August and October. January is also vulnerable for 29 (not every year), 30 and 31.
To use '+1 month', rely on 'first day of next month' or 'last day of next month' to extract the next month's name. For longer interfaces, start from 'first day of next month'.
<?php
// Base date is October 31 => 10/31
// +1 month adds +1 to 10 => 11/31
// Since November 31rst doesn't exists, it is corrected to 12/01.
echo date('F', strtotime('+1 month',mktime(0,0,0,$i,31,2017))).PHP_EOL;
// Base date is October 31 => 10/31
echo date('F', strtotime('first day of next month',mktime(0,0,0,$i,31,2017))).PHP_EOL;
?>
Note that Datetime and DatetimeImmutable are also subject to the same trap.
See also and It is the 31st again
Printf Number Of Arguments
[Since 1.0.1] - [ -P Structures/PrintfArguments ] - [ Online docs ]
The number of arguments provided to printf(), vprintf() and vsprintf() doesn't match the format string.
Extra arguments are ignored, and are dead code as such. Missing arguments are reported with a warning, and nothing is displayed.
Omitted arguments produce an error.
See also printf, sprintf and vsprintf
Drupal Usage
[Since 1.0.3] - [ -P Vendors/Drupal ] - [ Online docs ]
This analysis reports usage of the Drupal CMS. The report is based on the usage of Drupal namespace.
<?php
namespace Drupal\example\Controller;
use Drupal\Core\Controller\ControllerBase;
/**
* An example controller.
*/
class ExampleController extends ControllerBase {
/**
* {@inheritdoc}
*/
public function content() {
$build = array(
'#type' => 'markup',
'#markup' => t('Hello World!'),
);
return $build;
}
}
?>
See also and Drupal
Ambiguous Static
[Since 1.0.3] - [ -P Classes/AmbiguousStatic ] - [ Online docs ]
Methods or properties with the same name, are defined static in one class, and not static in another. This is error prone, as it requires a good knowledge of the code to make it static or not.
Try to keep the methods simple and unique. Consider renaming the methods and properties to distinguish them easily. A method and a static method have probably different responsibilities.
<?php
class a {
function mixedStaticMethod() {}
}
class b {
static function mixedStaticMethod() {}
}
/... a lot more code later .../
$c->mixedStaticMethod();
// or
$c::mixedStaticMethod();
?>
Phalcon Usage
[Since 1.0.3] - [ -P Vendors/Phalcon ] - [ Online docs ]
This analysis reports usage of the Phalcon Framework. The report is based on the usage of Phalcon namespace, which may be provided by PHP code inclusion or the PHP extension.
<?php
use Phalcon\Mvc\Application;
// Register autoloaders
// Register services
// Handle the request
$application = new Application($di);
try {
$response = $application->handle();
$response->s`end() <https://www.php.net/end>`_;
} catch (\Exception $e) {
echo 'Exception: ', $e->getMessage();
}
?>
See also and Phalcon
Fuel PHP Usage
[Since 1.0.3] - [ -P Vendors/Fuel ] - [ Online docs ]
This analysis reports usage of the Fuel PHP Framework.
<?php
// file located in APPPATH/classes/presenter.php
class Presenter extends \Fuel\Core\Presenter
{
// namespace prefix
protected static $ns_prefix = 'Presenter\';
}?>
Do not confuse fuelPHP and fuelCMS
See also and FuelPHP
Don't Send $this In Constructor
[Since 1.0.4] - [ -P Classes/DontSendThisInConstructor ] - [ Online docs ]
Don't use $this as an argument while in the __construct(). Until the constructor is finished, the object is not finished, and may be in an unstable state. Providing it to another code may lead to error.
This is true when the receiving structure puts the incoming object immediately to work, and don't store it for later use.
<?php
// $this is only provided when Foo is constructed
class Foo {
private $bar = null;
private $data = array();
static public function build($data) {
$foo = new Foo($data);
// Can't build in one call. Must make it separate.
$foo->finalize();
}
private function __construct($data) {
// $this is provided too early
$this->data = $data;
}
function finalize() {
$this->bar = new Bar($this);
}
}
// $this is provided too early, leading to error in Bar
class Foo2 extends Foo {
private $bar = null;
private $data = array();
function __construct($data) {
// $this is provided too early
$this->bar = new Bar($this);
$this->data = $data;
}
}
class Bar {
function __construct(Foo $foo) {
// the cache is now initialized with a wrong
$this->cache = $foo->getIt();
}
}
?>
See also and Don't pass this out of a constructor
Argon2 Usage
[Since 1.0.4] - [ -P Php/Argon2Usage ] - [ Online docs ]
Argon2 is an optionally compiled password hashing API.
Argon2 has been added to the password hashing API in PHP 7.2.
It is not available in older version. It also requires PHP to be compiled with the --with-password-argon2 option.
<?php
// Hashing a password with argon2
$hash = password_hash('password', PASSWORD_ARGON2I, ['memory_cost' => 1<<17,
'time_cost' => PASSWORD_ARGON2_DEFAULT_TIME_COST,
'threads' => PASSWORD_ARGON2_DEFAULT_THREADS]);
?>
See also and Argon2 Password Hash
Crypto Usage
[Since 1.0.4] - [ -P Php/CryptoUsage ] - [ Online docs ]
Usage of cryptography and hashes functions.
The functions listed are the native PHP functions, and do not belong to a specific extension, like OpenSSL , mcrypt or mhash .
Cryptography and hashes are mainly used for storing sensitive data, such as passwords, or to verify authenticity of data. They may also be used for name-randomization with cache.
<?php
if (md5($_POST['password']) === $row['password_hash']) {
user_login($user);
} else {
error('Wrong password');
}
?>
See also and Cryptography Extensions
No get_class() With Null
[Since 1.0.4] - [ -P Structures/NoGetClassNull ] - [ Online docs ]
It is not possible to pass explicitly null to get_class() to get the current's class name. Since PHP 7.2, one must call get_class() without arguments to achieve that result.
<?php
class A {
public function f() {
// Gets the classname
$classname = get_class();
// Gets the classname and a warning
$classname = get_class(null);
}
}
$a = new A();
$a->f('get_class');
?>
Maybe Missing New
[Since 1.0.4] - [ -P Structures/MissingNew ] - [ Online docs ]
This functioncall looks like a class instantiation that is missing the new keyword.
Any function definition was found for that function, but a class with that name was. New is probably missing.
<?php
// Functioncall
$a = foo();
// Class definition
class foo {}
// Function definition
function foo {}
// Functioncall
$a = BAR;
// Function definition
class bar {}
// Constant definition
const BAR = 1;
?>
Unknown Pcre2 Option
[Since 1.0.4] - [ -P Php/UnknownPcre2Option ] - [ Online docs ]
PCRE2 supports different options, compared to PCRE1 . PCRE2 was adopted with PHP 7.3.
The S modifier : it used to tell PCRE to spend more time studying the regex, so as to be faster at execution. This is now the default behavior, and may be dropped from the regex.
The X modifier : X is still existing with PCRE2 , though it is now the default for PCRE2 , and not for PHP as time of writing. In particular, Any backslash in a pattern that is followed by a letter that has no special meaning causes an error, thus reserving these combinations for future expansion. . It is recommended to avoid using useless sequence \s in regex to get ready for that change. All the following letters gijkmoqyFIJMOTY . Note that clLpPuU are valid PRCE sequences, and are probably failing for other reasons.
<?php
// \y has no meaning. With X option, this leads to a regex compilation error, and a failed test.
preg_match('/ye\y/', $string);
preg_match('/ye\y/X', $string);
?>
See also Pattern Modifiers and PHP RFC: PCRE2 migration
Type Array Index
[Since 1.0.4] - [ -P Type/ArrayIndex ] - [ Online docs ]
All literal index used in the code.
<?php
// index is an index. it is read
$array['index'] = 1;
// another_index and second_level are read
$array[] = $array['another_index']['second_level'];
// variables index are not reported
$array[$variable] = 1;
?>
Incoming Variable Index Inventory
[Since 1.0.4] - [ -P Type/GPCIndex ] - [ Online docs ]
This collects all the index used in incoming variables : $_GET, $_POST, $_REQUEST, $_COOKIE.
<?php
// x is collected
echo $_GET['x'];
// y is collected, but no z.
echo $_POST['y']['z'];
// a is not collected
echo $_ENV['s'];
?>
ext/vips
[Since 1.0.4] - [ -P Extensions/Extvips ] - [ Online docs ]
Extension VIPS.
The VIPS image processing system is a very fast, multi-threaded image processing library with low memory needs.
<?php
dl('vips.' . PHP_SHLIB_SUFFIX);
$x = vips_image_new_from_file($argv[1])[out];
vips_image_write_to_file($x, $argv[2]);
?>
See also php-vips-ext, libvips and libvips adapter for PHP Imagine
Dl() Usage
[Since 1.0.4] - [ -P Php/DlUsage ] - [ Online docs ]
Dynamically load PHP extensions with dl().
<?php
// dynamically loading ext/vips
dl('vips.' . PHP_SHLIB_SUFFIX);
?>
See also and dl
Parent First
[Since 1.0.5] - [ -P Classes/ParentFirst ] - [ Online docs ]
When calling parent constructor, always put it first in the __construct method.
It ensures the parent is correctly build before the child start using values.
<?php
class father {
protected $name = null;
function __construct() {
$this->name = init();
}
}
class goodSon {
function __construct() {
// parent is build immediately,
parent::__construct();
echo my name is.$this->name;
}
}
class badSon {
function __construct() {
// This will fail.
echo my name is.$this->name;
// parent is build later,
parent::__construct();
}
}
?>
This analysis doesn't apply to Exceptions.
Environment Variables
[Since 1.0.5] - [ -P Variables/UncommonEnvVar ] - [ Online docs ]
Environment variables are used to interact with the hosting system.
They often provides configuration parameter that are set by the host of the application to be used.
That way, information is not hardcoded in the application, and may be changed at production.
<?php
//ENVIRONMENT set the production context
if (getenv('ENVIRONMENT') === 'Production') {
$sshKey = getenv('HOST_KEY');
} elseif (getenv('ENVIRONMENT') === 'Developper') {
$sshKey = 'NO KEY';
} else {
header('No website here.');
die();
}
?>
See also and $_ENV
Invalid Regex
[Since 1.0.5] - [ -P Structures/InvalidRegex ] - [ Online docs ]
The PCRE regex doesn't compile. It isn't a valid regex.
Several reasons may lead to this situation : syntax error, Unknown modifier, missing parenthesis or reference.
<?php
// valid regex
preg_match('/[abc]/', $string);
// invalid regex (missing terminating ] for character class
preg_match('/[abc/', $string);
?>
Regex are check with the Exakat version of PHP.
Dynamic regex are only checked for simple values. Dynamic values may eventually generate a compilation error.
Use Named Boolean In Argument Definition
[Since 1.0.6] - [ -P Functions/AvoidBooleanArgument ] - [ Online docs ]
Boolean values in argument definition are confusing.
It is recommended to use explicit constant names or enumerations, instead. They are more readable. They also allow for easy replacement when the code evolve and has to replace those booleans by strings. This works even also with classes, and class constants.
<?php
function flipImage($im, $horizontal = NO_HORIZONTAL_FLIP, $vertical = NO_VERTICAL_FLIP) { }
// with constants
const HORIZONTAL_FLIP = true;
const NO_HORIZONTAL_FLIP = true;
const VERTICAL_FLIP = true;
const NO_VERTICAL_FLIP = true;
rotateImage($im, HORIZONTAL_FLIP, NO_VERTICAL_FLIP);
// without constants
function flipImage($im, $horizontal = false, $vertical = false) { }
rotateImage($im, true, false);
?>
See also Improve Passing Booleans in PHP , Flag Argument and Improve Passing Booleans in PHP
Same Variable Foreach
[Since 1.0.5] - [ -P Structures/AutoUnsetForeach ] - [ Online docs ]
A foreach which uses its own source as a blind variable is actually broken.
Actually, PHP makes a copy of the source before it starts the loop. As such, the same variable may be used for both source and blind value.
Of course, this is very confusing, to see the same variables used in very different ways.
The source will also be destroyed immediately after the blind variable has been turned into a reference.
<?php
$array = range(0, 10);
foreach($array as $array) {
print $array.PHP_EOL;
}
print_r($array); // display number from 0 to 10.
$array = range(0, 10);
foreach($array as &$array) {
print $array.PHP_EOL;
}
print_r($array); // display 10
?>
Never Called Parameter
[Since 1.0.6] - [ -P Functions/NeverUsedParameter ] - [ Online docs ]
When a parameter is never used at calltime. It always falls back to its default value : then, it may be turned into a local variable.
Parameter without a default value are reported by PHP, and are usually always filled.
<?php
// $b may be turned into a local var, it is unused
function foo($a, $b = 1) {
return $a + $b;
}
// whenever foo is called, the 2nd arg is not mentioned
foo($a);
foo(3);
foo('a');
foo($c);
?>
This analysis checks for actual usage of the parameter, from the outside of the method. This is different from checking if the parameter is used inside the method.
ext/igbinary
[Since 1.0.6] - [ -P Extensions/Extigbinary ] - [ Online docs ]
Extension igbinary.
igbinary is a drop in replacement for the standard php serializer. Instead of time and space consuming textual representation, igbinary stores php data structures in compact binary form.
<?php
$serialized = igbinary_serialize($variable);
$unserialized = igbinary_unserialize($serialized);
?>
See also and igbinary
Identical On Both Sides
[Since 1.0.8] - [ -P Structures/IdenticalOnBothSides ] - [ Online docs ]
Operands should be different when comparing or making a logical combination. Of course, the value each operand holds may be identical. When the same operand appears on both sides of the expression, the result is know before execution.
<?php
// Trying to confirm consistency
if ($login == $login) {
doSomething();
}
// Works with every operators
if ($object->login( ) !== $object->login()) {
doSomething();
}
if ($sum >= $sum) {
doSomething();
}
//
if ($mask && $mask) {
doSomething();
}
if ($mask || $mask) {
doSomething();
}
?>
Identical Consecutive Expression
[Since 1.0.8] - [ -P Structures/IdenticalConsecutive ] - [ Online docs ]
Identical consecutive expressions might be double code. They are worth being checked.
They may be a copy/paste with unmodified content. When the content has to be duplicated, it is recommended to avoid executing the expression again, and just access the cached result.
<?php
$current = $array[$i];
$next = $array[$i + 1];
$nextnext = $array[$i + 1]; // OOps, nextnext is wrong.
// Initialization
$previous = foo($array[1]); // previous is initialized with the first value on purpose
$next = foo($array[1]); // the second call to foo() with the same arguments should be avoided
// the above can be rewritten as :
$next = $previous; // save the processing.
for($i = 1; $i < 200; ++$i) {
$next = doSomething();
}
?>
No Reference For Ternary
[Since 1.0.8] - [ -P Php/NoReferenceForTernary ] - [ Online docs ]
The ternary operator and the null coalescing operator are both expressions that only return values, and not a variable.
This means that any provided reference will be turned into its value. While this is usually invisible, it will raise a warning when a reference is expected. This is the case with methods returning a reference.
A PHP notice is generated when using a ternary operator or the null coalesce operator : Only variable references should be returned by reference . The notice is also emitted when returning objects.
This applies to methods, functions and closures.
<?php
// This works
function &foo($a, $b) {
if ($a === 1) {
return $b;
} else {
return $a;
}
}
// This raises a warning, as the operator returns a value
function &foo($a, $b) { return $a === 1 ? $b : $a; }
?>
See also Null Coalescing Operator and Ternary Operator
Unused Inherited Variable In Closure
[Since 1.0.11] - [ -P Functions/UnusedInheritedVariable ] - [ Online docs ]
Some closures forgot to make usage of inherited variables.
Closure have two separate set of incoming variables : the arguments (between parenthesis) and the inherited variables, in the 'use' clause. Inherited variables are extracted from the local environment at creation time, and keep their value until execution.
The reported closures are requesting some local variables, but do not make any usage of them. They may be considered as dead code.
<?php
// In this closure, $y is forgotten, but $u is used.
$a = function ($y) use ($u) { return $u; };
// In this closure, $u is forgotten
$a = function ($y, $z) use ($u) { return $u; };
?>
See also and Anonymous functions
Inclusion Wrong Case
[Since 1.1.1] - [ -P Files/InclusionWrongCase ] - [ Online docs ]
Inclusion should follow exactly the case of included files and path. This prevents the infamous case-sensitive filesystem bug, where files are correctly included in a case-insensitive system, and failed to be when moved to production.
<?php
// There must exist a path called path/to and a file library.php with this case
include path/to/library.php;
// Error on the case, while the file does exist
include path/to/LIBRARY.php;
// Error on the case, on the PATH
include path/TO/library.php;
?>
See also and include_once
Missing Include
[Since 1.1.2] - [ -P Files/MissingInclude ] - [ Online docs ]
The included files doesn't exists in the repository. The inclusions target a files that doesn't exist.
The analysis works with every type of inclusion : include(), require(), include_once() and require_once(). It also works with parenthesis when used as parameter delimiter.
The analysis doesn't take into account include_path . This may yield false positives.
<?php
include 'non_existent.php';
// variables are not resolved. This won't be reported.
require ($path.'non_existent.php');
?>
Missing included files may lead to a fatal error, a warning or other error later in the execution.
Useless Referenced Argument
[Since 1.1.3] - [ -P Functions/UselessReferenceArgument ] - [ Online docs ]
The argument has a reference, but is only used for reading.
This is probably a development artefact that was forgotten. It is better to remove it.
This analysis also applies to foreach() loops, that declare the blind variable as reference, then use the variable as an object, accessing properties and methods. When a variable contains an object, there is no need to declare a reference : it is a reference automatically.
<?php
function foo($a, &$b, &$c) {
// $c is passed by reference, but only read. The reference is useless.
$b = $c + $a;
// The reference is useful for $b
}
foreach ($array as &$element) {
$element->method();
}
?>
See also and Objects and references
Fallback Function
[Since 1.1.4] - [ -P Functions/FallbackFunction ] - [ Online docs ]
A function that is called with its name alone, and whose definition is in the global scope.
<?php
namespace {
// global definition
function foo() {}
}
namespace Bar {
// local definition
function foo2() {}
foo(); // definition is in the global namespace
foo2(); // definition is in the Bar namespace
}
?>
See also and Using namespaces: fallback to global function/constant
Useless Catch
[Since 1.1.4] - [ -P Exceptions/UselessCatch ] - [ Online docs ]
A catch clause should handle the exception by doing something.
Among the task of a catch clause : log the exception, clean any mess that was introduced, fail graciously.
<?php
function foo($a) {
try {
$b = doSomething($a);
} catch (Throwable $e) {
// No log of the exception : no one knows it happened.
// return immediately ?
return false;
}
$b->complete();
return $b;
}
?>
See also Exceptions and Best practices for PHP exception handling
Possible Infinite Loop
[Since 1.1.5] - [ -P Structures/PossibleInfiniteLoop ] - [ Online docs ]
Loops on files that can't be open results in infinite loop.
fgets(), and functions like fgetss(), fgetcsv(), fread(), return false when they finish reading, or can't access the file.
In case the file is not accessible, comparing the result of the reading to something that is falsy, leads to a permanent valid condition. The execution will only finish when the max_execution_time is reached.
<?php
$file = fopen('/path/to/file.txt', 'r');
// when `fopen() <https://www.php.net/fopen>`_ fails, the next loops is infinite
// `fgets() <https://www.php.net/fgets>`_ will always return false, and while will always be true.
while($line = fgets($file) != 'a') {
doSomething();
}
?>
It is recommended to check the file resources when they are opened, and always use === or !== to compare readings. feof() is also a reliable function here.
ext/hrtime
[Since 1.1.5] - [ -P Extensions/Exthrtime ] - [ Online docs ]
High resolution timing Extension.
The HRTime extension implements a high resolution `StopWatch` class. It uses the best possible API on different platforms which brings resolution up to nanoseconds. It also makes possible to implement a custom stopwatch using low level ticks delivered by the underlaying system.
<?php
$c = new HRTime\StopWatch;
$c->start();
/* measure this code block execution */
for ($i = 0; $i < 1024*1024; $i++);
$c->stop();
$elapsed0 = $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);
/* measurement is not running here*/
for ($i = 0; $i < 1024*1024; $i++);
$c->start();
/* measure this code block execution */
for ($i = 0; $i < 1024*1024; $i++);
$c->stop();
$elapsed1 = $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);
$elapsed_total = $c->getElapsedTime(HRTime\Unit::NANOSECOND);
?>
See also and ext/hrtime manual
Test Then Cast
[Since 1.1.6] - [ -P Structures/TestThenCast ] - [ Online docs ]
A test is run on a value without a cast, and later the cast value is later used.
The cast may introduce a distortion to the value, and still lead to the unwanted situation. For example, comparing to 0, then later casting to an int. The comparison to 0 is done without casting, and as such, 0.1 is different from 0. Yet, (int) 0.1 is actually 0, leading to a Division by 0 error.
<?php
// Here. $x may be different from 0, but (int) $x may be 0
$x = 0.1;
if ($x != 0) {
$y = 4 / (int) $x;
}
// Safe solution : check the cast value.
if ( (int) $x != 0) {
$y = 4 / (int) $x;
}
?>
Foreach On Object
[Since 1.1.6] - [ -P Php/ForeachObject ] - [ Online docs ]
Foreach on object looks like a typo. This is particularly true when both object and member are variables.
Foreach on an object member is a legit PHP syntax, though it is very rare : blind variables rarely have to be securing in an object to be processed.
<?php
// This is the real thing
foreach($array as $o => $b) {
doSomething();
}
// Looks suspicious
foreach($array as $o -> $b) {
doSomething();
}
?>
ext/xxtea
[Since 1.1.7] - [ -P Extensions/Extxxtea ] - [ Online docs ]
Extension xxtea : XXTEA encryption algorithm extension for PHP.
XXTEA is a fast and secure encryption algorithm. This is a XXTEA extension for PHP.
It is different from the original XXTEA encryption algorithm. It encrypts and decrypts string instead of uint32 array, and the key is also string.
<?php
// Example is extracted from the xxtea repository on github : tests/xxtea.phpt
$str = 'Hello World! 你好，中国🇨🇳！';
$key = '1234567890';
$base64 = 'D4t0rVXUDl3bnWdERhqJmFIanfn/6zAxAY9jD6n9MSMQNoD8TOS4rHHcGuE=';
$encrypt_data = xxtea_encrypt($str, $key);
$decrypt_data = xxtea_decrypt($encrypt_data, $key);
if ($str == $decrypt_data && base64_encode($encrypt_data) == $base64) {
echo 'success!';
} else {
echo base64_encode($encrypt_data);
echo 'fail!';
}
?>
See also PECL ext/xxtea and ext/xxtea on Github
ext/uopz
[Since 1.1.7] - [ -P Extensions/Extuopz ] - [ Online docs ]
Extension UOPZ : User Operations for Zend.
The uopz extension is focused on providing utilities to aid with unit testing PHP code.
It supports the following activities: Intercepting function execution, Intercepting object creation, Hooking into function execution, Manipulation of function statics, Manipulation of function flags, Redefinition of constants, Deletion of constants, Runtime creation of functions and methods,
<?php
// The example is extracted from the UOPZ extension test suite : tests/001.phpt
class Foo {
public function bar(int $arg) : int {
return $arg;
}
}
var_dump(uopz_set_return(Foo::class, 'bar', true));
$foo = new Foo();
var_dump($foo->bar(1));
uopz_set_return(Foo::class, 'bar', function(int $arg) : int {
return $arg * 2;
}, true);
var_dump($foo->bar(2));
try {
uopz_set_return(Foo::class, 'nope', 1);
} catch(Throwable $t) {
var_dump($t->getMessage());
}
class Bar extends Foo {}
try {
uopz_set_return(Bar::class, 'bar', null);
} catch (Throwable $t) {
var_dump($t->getMessage());
}
uopz_set_something(Bar::class, 'bar', null);
?>
See also ext/uopz and User Operations for Zend
ext/varnish
[Since 1.1.7] - [ -P Extensions/Extvarnish ] - [ Online docs ]
Extension PHP for varnish.
Varnish Cache is an open source, state of the art web application accelerator. The extension makes it possible to interact with a running varnish instance through TCP socket or shared memory.
<?php
$args = array(
VARNISH_CONFIG_HOST => '::1',
VARNISH_CONFIG_PORT => 6082,
VARNISH_CONFIG_SECRET => '5174826b-8595-4958-aa7a-0609632ad7ca',
VARNISH_CONFIG_TIMEOUT => 300,
);
$va = new VarnishAdmin($args);
?>
See also ext/varnish and pecl/Varnish
ext/opencensus
[Since 1.1.7] - [ -P Extensions/Extopencensus ] - [ Online docs ]
Extension PHP for OpenCensus.
A stats collection and distributed tracing framework.
<?php
opencensus_trace_begin('root', ['spanId' => '1234']);
opencensus_trace_add_annotation('foo');
opencensus_trace_begin('inner', []);
opencensus_trace_add_annotation('asdf', ['spanId' => '1234']);
opencensus_trace_add_annotation('abc');
opencensus_trace_finish();
opencensus_trace_finish();
$traces = opencensus_trace_list();
echo Number of traces: . count($traces) . \n;
$span = $traces[0];
print_r($span->timeEvents());
$span2 = $traces[1];
print_r($span2->timeEvents());
?>
See also and opencensus
ext/leveldb
[Since 1.1.7] - [ -P Extensions/Extleveldb ] - [ Online docs ]
PHP Binding for LevelDB.
LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.
<?php
$db = new LevelDB($leveldb_path);
$batch = new LevelDBWriteBatch();
$batch->set('batch_foo', 'batch_bar');
$batch->put('batch_foo2', 'batch_bar2');
$batch->delete('batch_foo');
$db->write($batch);
$batch->clear();
$batch->delete('batch_foo2');
$batch->set('batch_foo', 'batch again');
?>
See also ext/leveldb on Github and Leveldb
Property Could Be Local
[Since 1.1.7] - [ -P Classes/PropertyCouldBeLocal ] - [ Online docs ]
A property only used in one method may be turned into a local variable.
Public an protected properties are omitted here : they may be modified somewhere else, in the code. This analysis may be upgraded to support those properties, when tracking of such properties becomes available.
Classes where only one non-magic method is available are omitted.
Traits with private properties are processed the same way.
<?php
class x {
private $foo = 1;
// Magic method, and constructor in particular, are omitted.
function __construct($foo) {
$this->foo = $foo;
}
function bar() {
$this->foo++;
return $this->foo;
}
function barbar() {}
}
?>
ext/db2
[Since 1.1.8] - [ -P Extensions/Extdb2 ] - [ Online docs ]
Extension for IBM DB2, Cloudscape and Apache Derby.
This extension gives access to IBM DB2 Universal Database, IBM Cloudscape, and Apache Derby databases using the DB2 Call Level Interface (DB2 CLI).
<?php
$conn = db2_connect($database, $user, $password);
if ($conn) {
$stmt = db2_exec($conn, 'SELECT count(*) FROM animals');
$res = db2_fetch_array( $stmt );
echo $res[0] . PHP_EOL;
// Turn AUTOCOMMIT off
db2_autocommit($conn, DB2_AUTOCOMMIT_OFF);
// Delete all rows from ANIMALS
db2_exec($conn, 'DELETE FROM animals');
$stmt = db2_exec($conn, 'SELECT count(*) FROM animals');
$res = db2_fetch_array( $stmt );
echo $res[0] . PHP_EOL;
// Roll back the DELETE statement
db2_rollback( $conn );
$stmt = db2_exec( $conn, 'SELECT count(*) FROM animals' );
$res = db2_fetch_array( $stmt );
echo $res[0] . PHP_EOL;
db2_close($conn);
}
?>
See also and IBM Db2
Too Many Native Calls
[Since 1.1.10] - [ -P Php/TooManyNativeCalls ] - [ Online docs ]
Avoid stuffing too many PHP native call inside another functioncall.
For readability reasons, or, more often, for edge case handling, it is recommended to avoid nesting too many PHP native calls.
This analysis reports any situation where more than 3 PHP native calls are nested.
<?php
// Too many nested functions
$cleanArray = array_unique(array_keys(array_count_values(array_column($source, 'x'))));
// Avoid warning when source is empty
$extract = array_column($source, 'x');
if (empty($extract)) {
$cleanArray = array();
} else {
$cleanArray = array_unique(array_keys(array_count_values($extract)));
}
// This is not readable, although it is short.
// It may easily get out of hand.
echo chr(80), chr(72), chr(80), chr(32), ' is great!';
?>
Don't Unset Properties
[Since 1.2.3] - [ -P Classes/DontUnsetProperties ] - [ Online docs ]
Don't unset properties. They would go undefined, and raise warnings of undefined properties, even though the property is explicitly defined in the original class.
When getting rid of a property, assign it to `null`. This keeps the property defined in the object, yet allows existence check without errors.
<?php
class Foo {
public $a = 1;
}
$a = new Foo();
var_dump((array) $a) ;
// la propriété est reportée, et null
// ['a' => null]
unset($a->a);
var_dump((array) $a) ;
//Empty []
// Check if a property exists
var_dump($a->b === null);
// Same result as above, but with a warning
var_dump($a->c === null);
?>
This analysis works on properties and static properties. It also reports magic properties being unset.
Thanks for Benoit Burnichon for the original idea.
Strtr Arguments
[Since 1.2.3] - [ -P Php/StrtrArguments ] - [ Online docs ]
Strtr() replaces characters by others in a string. When using strings, strtr() replaces characters as long as they have a replacement. All others are ignored.
In particular, strtr() works on strings of the same size, and cannot be used to remove chars.
<?php
$string = 'abcde';
echo strtr($string, 'abc', 'AB');
echo strtr($string, 'ab', 'ABC');
// displays ABcde
// c is ignored each time
// strtr can't remove a char
echo strtr($string, 'a', '');
// displays a
?>
See also and strtr
Missing Parenthesis
[Since 1.2.6] - [ -P Structures/MissingParenthesis ] - [ Online docs ]
Add parenthesis to those expression to prevent bugs.
<?php
// Missing some parenthesis!!
if (!$a instanceof Stdclass) {
print Not\n;
} else {
print Is\n;
}
// Could this addition be actually
$c = -$a + $b;
// This one ?
$c = -($a + $b);
?>
See also and Operators Precedence
Callback Function Needs Return
[Since 1.2.6] - [ -P Functions/CallbackNeedsReturn ] - [ Online docs ]
When used with array_map() functions, the callback must return something. This return may be in the form of a return statement, a global variable or a parameter with a reference. All those solutions extract information from the callback.
<?php
// This filters each element
$filtered = array_filter($array, function ($x) {return $x == 2; });
// This return void for every element
$filtered = array_filter($array, function ($x) {return ; });
// costly `array_sum() <https://www.php.net/array_sum>`_
$sum = 0;
$filtered = array_filter($array, function ($x) use (&$sum) {$sum += $x; });
// costly `array_sum() <https://www.php.net/array_sum>`_
global $sum = 0;
$filtered = array_filter($array, function () {global $sum; $sum += $x; });
// register_shutown_function() doesn't require any return
register_shutown_function(my_shutdown);
?>
The following functions are omitted, as they don't require the return :
+ forward_static_call_array()
+ forward_static_call()
+ register_shutdown_function()
+ register_tick_function()
Wrong Range Check
[Since 1.2.5] - [ -P Structures/WrongRange ] - [ Online docs ]
The interval check should use && and not ||.
<?php
//interval correctly checked a is between 2 and 999
if ($a > 1 && $a < 1000) {}
//interval incorrectly checked : a is 2 or more ($a < 1000 is never checked)
if ($a > 1 || $a < 1000) {}
?>
ext/zookeeper
[Since 1.2.5] - [ -P Extensions/Extzookeeper ] - [ Online docs ]
Extension for Apache Zookeeper.
ZooKeeper is an Apache project that enables centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.
<?php
$zookeeper = new Zookeeper('locahost:2181');
$path = '/path/to/node';
$value = 'nodevalue';
$zookeeper->set($path, $value);
$r = $zookeeper->get($path);
if ($r)
echo $r;
else
echo 'ERR';
?>
See also ext/zookeeper, Install Zookeeper PHP Extension and Zookeeper
ext/cmark
[Since 1.2.7] - [ -P Extensions/Extcmark ] - [ Online docs ]
Extension Cmark, for Common Mark.
cmark provides access to the reference implementation of CommonMark, a rationalized version of Markdown syntax with a specification.
<?php
$text = new CommonMark\Node\Text;
$text->literal = 'Hello World';
$document = new CommonMark\Node\Document;
$document->appendChild(
(new CommonMark\Node\Paragraph)
->appendChild($text));
echo CommonMark\Render\HTML($document);
?>
See also Cmark and ext/cmark
Can't Instantiate Class
[Since 1.2.8] - [ -P Classes/CantInstantiateClass ] - [ Online docs ]
When constructor is not public, it is not possible to instantiate such a class. Either this is a conception choice, or there are factories to handle that. Either way, it is not possible to call new on such class.
<?php
//This is the way to go
$x = X::factory();
//This is not possible
$x = new X();
class X {
//This is also the case with proctected __construct
private function __construct() {}
static public function factory() {
return new X();
}
}
?>
See also In a PHP5 class, when does a private constructor get called?, Named Constructors in PHP and PHP Constructor Best Practices And The Prototype Pattern
strpos() Too Much
[Since 1.2.8] - [ -P Performances/StrposTooMuch ] - [ Online docs ]
strpos() covers the whole string before reporting 0. If the expected string is expected be at the beginning, or a fixed place, it is more stable to use substr() for comparison.
The longer the haystack (the searched string), the more efficient is that trick. The string has to be 10k or more to have impact, unless it is in a loop.
<?php
// This always reads the same amount of string
if (substr($html, 0, 6) === '<html>') {
}
// When searching for a single character, checking with a known position ($string[$position]) is even faster
if ($html[0] === '<') {
}
// With `strpos() <https://www.php.net/strpos>`_, the best way is to search for something that exist, and use absence as worst case scenario
if (strpos($html, '<html>') > 0) {
} else {
//
}
// When the search fails, the whole string has been read
if (strpos($html, '<html>') === 0) {
}
?>
This applies to stripos() too.
Typehinted References
[Since 1.2.8] - [ -P Functions/TypehintedReferences ] - [ Online docs ]
Typehinted arguments have no need for references. Since they are only an object, they are already a reference.
In fact, adding the & on the argument definition may lead to error like Only variables should be passed by reference .
This applies to the object type hint, but not the the others, such as int or bool .
<?php
// a class
class X {
public $a = 3;
}
// typehinted reference
//function foo(object &$x) works too
function foo(X &$x) {
$x->a = 1;
return $x;
}
// Send an object
$y = foo(new X);
// This prints 1;
print $y->a;
?>
See also Passing by reference and Objects and references
Weak Typing
[Since 1.2.8] - [ -P Classes/WeakType ] - [ Online docs ]
The variable's validation is not enough to allow for a sophisticated usage. For example, the variable is checked for null, then used as an object or an array.
<?php
if ($a !== null) {
echo $a->b;
}
?>
See also and From assumptions to assertions
Method Signature Must Be Compatible
[Since 1.2.9] - [ -P Classes/MethodSignatureMustBeCompatible ] - [ Online docs ]
Make sure methods signature are compatible.
PHP generates the infamous Fatal error at execution : Declaration of FooParent::Bar() must be compatible with FooChildren::Bar()
<?php
class x {
function xa() {}
}
class xxx extends xx {
function xa($a) {}
}
?>
Mismatch Type And Default
[Since 1.2.9] - [ -P Functions/MismatchTypeAndDefault ] - [ Online docs ]
The argument typehint and its default value don't match.
The code may lint and load, and even work when the arguments are provided. Though, PHP won't eventually execute it.
Most of the mismatch problems are caught by PHP at linting time. It displays the following error message : 'Argument 1 passed to foo() must be of the type integer, string given'.
The default value may be a constant (normal or class constant) : as such, PHP might find its value only at execution time, from another include. As such, PHP doesn't report anything about the situation at compile time.
The default value may also be a constant scalar expression : since PHP 7, some of the simple operators such as +, -, *, %, **, etc. are available to build default values. Among them, the ternary operator and Coalesce. Again, those expression may be only evaluated at execution time, when the value of the constants are known.
<?php
// bad definition : the string is actually an integer
const STRING = 3;
function foo(string $s = STRING) {
echo $s;
}
// works without problem
foo('string');
// Fatal error at compile time
foo();
// Fail only at execution time (missing D), and when default is needed
function foo2(string $s = D ? null : array()) {
echo $s;
}
?>
PHP reports typehint and default mismatch at compilation time, unless there is a static expression that can't be resolved within the compiled file : then it is checked only at runtime, leading to a Fatal error.
See also Type declarations, Functions/WrongReturnedType, Functions/MismatchTypeAndDefault and Classes/WrongTypedPropertyInit
Check JSON
[Since 1.3.0] - [ -P Structures/CheckJson ] - [ Online docs ]
Check errors whenever JSON is encoded or decoded.
In particular, NULL is a valid decoded JSON response. If you want to avoid mistaking NULL for an error, it is recommended to call json_last_error .
<?php
$encoded = json_encode($incoming);
// Unless JSON must contains some non-null data, this mistakes NULL and error
if(json_last_error() != JSON_ERROR_NONE) {
die('Error when encoding JSON');
}
$decoded = json_decode($incoming);
// Unless JSON must contains some non-null data, this mistakes NULL and error
if($decoded === null) {
die('ERROR');
}
?>
See also Option to make json_encode and json_decode throw exceptions on errors,
json_last_error.
Const Visibility Usage
[Since 1.3.0] - [ -P Classes/ConstVisibilityUsage ] - [ Online docs ]
Visibility for class constant controls the accessibility to class constant.
A public constant may be used anywhere in the code; a protected constant usage is restricted to the class and its relatives; a private constant is restricted to itself.
This feature was introduced in PHP 7.1. It is recommended to use explicit visibility, and, whenever possible, make the visibility private.
<?php
class x {
public const a = 1;
protected const b = 2;
private const c = 3;
const d = 4;
}
interface i {
public const a = 1;
const d = 4;
}
?>
See also Class Constants and PHP RFC: Support Class Constant Visibility
Dont Mix ++
[Since 1.3.2] - [ -P Structures/DontMixPlusPlus ] - [ Online docs ]
++ operators, pre and post, have two distinct behaviors, and should be used separately.
When mixed in a larger expression, they are difficult to read, and may lead to unwanted behaviors.
<?php
// Clear and defined behavior
$i++;
$a[$i] = $i;
// The index is also incremented, as it is used AFTP the incrementation
// With $i = 2; $a is array(3 => 3)
$a[$i] = ++$i;
// $i is actually modified twice
$i = --$i + 1;
?>
See also and EXP30-C. Do not depend on the order of evaluation for side effects
Can't Throw Throwable
[Since 1.3.3] - [ -P Exceptions/CantThrow ] - [ Online docs ]
Classes extending Throwable can't be thrown, unless they also extend Exception . The same applies to interfaces that extends Throwable .
Although such code lints, PHP throws a Fatal error when executing or including it : Class fooThrowable cannot implement interface Throwable, extend Exception or Error instead .
<?php
// This is the way to go
class fooException extends \Exception { }
// This is not possible and a lot of work
class fooThrowable implements \throwable { }
?>
See also Throwable, Exception and Error
Abstract Or Implements
[Since 1.3.3] - [ -P Classes/AbstractOrImplements ] - [ Online docs ]
A class must implements all abstract methods of it parent, or be abstract too.
While PHP lints this code, it won't execute it and stop with a Fatal Error : Class BA contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (A::aFoo) .
<?php
abstract class Foo {
abstract function FooBar();
}
// This is in another file : php -l would detect it right away
class FooFoo extends Foo {
// The method is not defined.
// The class must be abstract, just like Foo
}
?>
See also and Class Abstraction
ext/eio
[Since 1.3.3] - [ -P Extensions/Exteio ] - [ Online docs ]
Extension EIO.
This is a PHP extension wrapping functions of the libeio library written by Marc Lehmann.
Libeio is a an asynchronous I/O library. Features basically include asynchronous versions of POSIX API(read, write, open, close, stat, unlink, fdatasync, mknod, readdir etc.); sendfile (native on Solaris, Linux, HP-UX, FreeBSD); readahead. libeio itself emulates the system calls, if they are not available on specific(UNIX-like) platform.
<?php
$str = str_repeat('1', 20);
$filename = '/tmp/tmp_file' .`uniqid() <https://www.php.net/uniqid>`_;
@unlink($filename);
touch($filename);
eio_open($filename, EIO_O_RDWR, NULL, EIO_PRI_DEFAULT, function($filename, $fd) use ($str) {
eio_write($fd, $str, strlen($str), 0, null, function($fd, $written) use ($str, $filename) {
var_dump([
'written' => $written,
'strlen' => strlen($str),
'filesize' => filesize($filename),
'count' => substr_count(file_get_contents($filename), '1')
]);
}, $fd);
}, $filename);
eio_event_loop();
?>
See also libeio and PHP extension for libeio
Incompatible Signature Methods
[Since 1.3.3] - [ -P Classes/IncompatibleSignature ] - [ Online docs ]
Methods should have the same signature when being overwritten.
The same signatures means the children class must have :
+ the same name
+ the same visibility or less restrictive
+ the same typehint or removed
+ the same default value or removed
+ a reference like its parent
This problem emits a fatal error, for abstract methods, or a warning error, for normal methods. Yet, it is difficult to lint, because classes are often stored in different files. As such, PHP do lint each file independently, as unknown parent classes are not checked if not present. Yet, when executing the code, PHP lint the actual code and may encounter a fatal error.
<?php
class a {
public function foo($a = 1) {}
}
class ab extends a {
// foo is overloaded and now includes a default value for $a
public function foo($a) {}
}
?>
See also and Object Inheritance
Ambiguous Visibilities
[Since 1.3.4] - [ -P Classes/AmbiguousVisibilities ] - [ Online docs ]
The properties have the same name, but have different visibilities, across different classes.
While it is legit to have a property with the same name in different classes, it may easily lead to confusion. As soon as the context is need to understand if the property is accessible or not, the readability suffers.
It is recommended to handle the same properties in the same way across classes, even when the classes are not related.
<?php
class person {
public $name;
private $address;
}
class gangster {
private $name;
public $nickname;
private $address;
}
$someone = Human::load(123);
echo 'Hello, '.$someone->name;
?>
Undefined ::class
[Since 1.3.5] - [ -P Classes/UndefinedStaticclass ] - [ Online docs ]
::class doesn't check if a corresponding class exists.
::class must be checked with a call to class_exists(). Otherwise, it may lead to a Class 'foo' not found or even silent dead code : this happens also with Catch and instanceof commands with undefined classes. PHP doesn't raise an error in that case.
<?php
class foo() {}
// prints foo
echo foo::class;
// prints bar though bar doesn't exist.
echo bar::class;
?>
See also and Class Constants
ext/lzf
[Since 1.3.5] - [ -P Extensions/Extlzf ] - [ Online docs ]
Extension LZF.
LZF is a very fast compression algorithm, ideal for saving space with only slight speed cost. It can be optimized for speed or space at the time of compilation.
<?php
$compressed = lzf_compress(This is test of LZF extension);
echo base64_encode($compressed);
?>
See also lzf and liblzf
ext/msgpack
[Since 1.3.5] - [ -P Extensions/Extmsgpack ] - [ Online docs ]
Extension msgPack.
This extension provide API for handling MessagePack serialization, both encoding and decoding.
<?php
$serialized = msgpack_serialize(array('a' => true, 'b' => 4));
$unserialized = msgpack_unserialize($serialized);
?>
See also msgpack for PHP and MessagePack
Case Insensitive Constants
[Since 1.3.9] - [ -P Constants/CaseInsensitiveConstants ] - [ Online docs ]
PHP constants used to be able to be case insensitive, when defined with define() and the third argument.
This feature is deprecated since PHP 7.3 and is removed since PHP 8.0.
<?php
// case sensitive
define('A', 1);
// case insensitive
define('B', 1, true);
echo A;
// This is not possible
//echo a;
// both possible
echo B;
echo b;
?>
See also and define
Handle Arrays With Callback
[Since 1.3.7] - [ -P Arrays/WithCallback ] - [ Online docs ]
Use functions like array_map().
<?php
// Handles arrays with callback
$uppercase = array_map('strtoupper', $source);
// Handles arrays with foreach
foreach($source as &$s) {
$s = uppercase($s);
}
?>
See also and array_map
Assert Function Is Reserved
[Since 1.3.9] - [ -P Php/AssertFunctionIsReserved ] - [ Online docs ]
Avoid defining an assert function in namespaces.
While they work fine when the assertions are active ( zend.assertions=1 ), calls to unqualified assert are optimized away when assertions are not active.
Since PHP 7.3, a fatal error is emitted : Defining a custom assert() function is deprecated, as the function has special semantics .
<?php
// Run this with zend.assertions=1 and
// Then run this with zend.assertions=0
namespace Test {
function `assert() <https://www.php.net/assert>`_ {
global $foo;
$foo = true;
}
}
namespace Test {
`assert() <https://www.php.net/assert>`_;
var_dump(isset($foo));
}
?>
See also assert and User-defined assert function is optimized away with zend.assertions=-1
Could Be Abstract Class
[Since 1.3.9] - [ -P Classes/CouldBeAbstractClass ] - [ Online docs ]
An abstract class is never instantiated, and has children class that are. As such, a 'parent' class that is never instantiated by itself, but has its own children instantiated could be marked as abstract.
That will prevent new code to try to instantiate it.
<?php
// Example code would actually be split over multiple files.
// That class could be abstract
class motherClass {}
// Those classes shouldn't be abstract
class firstChildren extends motherClass {}
class secondChildren extends motherClass {}
class thirdChildren extends motherClass {}
new firstChildren();
new secondChildren();
new thirdChildren();
//Not a single : new motherClass()
?>
See also Class Abstraction and Abstract classes and methods
Continue Is For Loop
[Since 1.3.9] - [ -P Structures/ContinueIsForLoop ] - [ Online docs ]
break and continue are very similar in PHP : they both break out of loop or switch. Yet, continue should be reserved for loops.
Since PHP 7.3, the execution emits a warning when finding a continue inside a switch : '"continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"?'
<?php
while ($foo) {
switch ($bar) {
case 'baz':
continue; // In PHP: Behaves like 'break;'
// In C: Behaves like 'continue 2;'
}
}
?>
See also and Deprecate and remove continue targeting switch
Trailing Comma In Calls
[Since 1.4.0] - [ -P Php/TrailingComma ] - [ Online docs ]
The last argument may be left empty.
This feature was introduced in PHP 7.3.
<?php
// VCS friendly call
// PHP 7.3 and more recent
foo(1,
2,
3,
);
// backward compatible call
// All PHP versions
foo(1,
2,
3
);
?>
See also and PHP RFC: Allow a trailing comma in function calls
Must Call Parent Constructor
[Since 1.4.1] - [ -P Php/MustCallParentConstructor ] - [ Online docs ]
Some PHP native classes require a call to parent::__construct() to be stable.
As of PHP 7.3, two classes currently need that call : SplTempFileObject and SplFileObject .
The error is only emitted if the class is instantiated, and a parent class is called.
<?php
class mySplFileObject extends \SplFileObject {
public function __construct() {
// Forgottent call to parent::__construct()
}
}
(new mySplFileObject())->`passthru() <https://www.php.net/passthru>`_;
?>
See also and Why, php? WHY???
Undefined Variable
[Since 1.4.2] - [ -P Variables/UndefinedVariable ] - [ Online docs ]
Variable that is used before any initialisation.
It is recommended to use a default value for every variable used. When not specified, the default value is set to NULL by PHP.
<?php
// Adapted from the PHP manual
$var = 'Bob';
$Var = 'Joe';
// The following line may emit a warning : Undefined variable: $undefined
echo $var, $Var, $undefined; // outputs Bob, Joe,
?>
Variable may be created in various ways : assignation, arguments, foreach blind variables, static and global variables.
This analysis doesn't handle dynamic variables, such as $$x . It also doesn't handle variables outside a method or function.
See also and Variable basics
Undefined Insteadof
[Since 1.4.2] - [ -P Traits/UndefinedInsteadof ] - [ Online docs ]
Insteadof tries to replace a method with another, but it doesn't exists. This happens when the replacing class is refactored, and some of its definition are dropped.
Insteadof may replace a non-existing method with an existing one, but not the contrary.
<?php
trait A {
function C (){}
}
trait B {
function C (){}
}
class Talker {
use A, B {
B::C insteadof A;
B::D insteadof A;
}
}
new Talker();
?>
This error is not linted : it only appears at execution time.
See also and Traits
Method Collision Traits
[Since 1.4.2] - [ -P Traits/MethodCollisionTraits ] - [ Online docs ]
Two or more traits are included in the same class, and they have methods collisions.
Those collisions should be solved with a use expression. When they are not, PHP stops execution with a fatal error : Trait method M has not been applied, because there are collisions with other trait methods on C .
<?php
trait A {
public function A() {}
public function M() {}
}
trait B {
public function B() {}
public function M() {}
}
class C {
use A, B;
}
class D {
use A, B{
B::M insteadof A;
};
}
?>
The code above lints, but doesn't execute.
See also and Traits
Class Could Be Final
[Since 1.4.3] - [ -P Classes/CouldBeFinal ] - [ Online docs ]
Any class that has no extension should be final by default.
As stated by Matthias Noback : If a class is not marked final, it has at least one subclass .
Prevent your classes from being subclassed by making them final . Sometimes, classes are not meant or thought to be derivable.
<?php
class x {} // This class is extended
class y extends x {} // This class is extended
class z extends y {} // This class is not extended
final class z2 extends y {} // This class is not extended
?>
See also Negative architecture, and assumptions about code and When to declare methods final
Inconsistent Elseif
[Since 1.4.3] - [ -P Structures/InconsistentElseif ] - [ Online docs ]
Chaining if/elseif requires a consistent string of conditions. The conditions are executed one after the other, and the conditions shouldn't overlap.
This analysis reports chains of elseif that don't share a common variable (or array, or property, etc.. ). As such, testing different conditions are consistent.
<?php
// $a is always common, so situations are mutually exclusive
if ($a === 1) {
doSomething();
} else if ($a > 1) {
doSomethingElse();
} else {
doSomethingDefault();
}
// $a is always common, so situations are mutually exclusive
// although, it may be worth checking the consistency here
if ($a->b === 1) {
doSomething();
} else if ($a->c > 1) {
doSomethingElse();
} else {
doSomethingDefault();
}
// if $a === 1, then $c doesn't matter?
// This happens, but then logic doesn't appear in the code.
if ($a === 1) {
doSomething();
} else if ($c > 1) {
doSomethingElse();
} else {
doSomethingDefault();
}
?>
Can't Disable Class
[Since 0.8.4] - [ -P Security/CantDisableClass ] - [ Online docs ]
This is the list of potentially dangerous PHP class being used in the code, such as \Phar.
<?php
// This script uses ftp_connect(), therefore, this function shouldn't be disabled.
$phar = new Phar();
?>
This analysis is the base for suggesting values for the disable_classes directive.
ext/seaslog
[Since 1.4.4] - [ -P Extensions/Extseaslog ] - [ Online docs ]
Extension Seaslog.
An effective,fast,stable log extension for PHP.
<?php
$basePath_1 = SeasLog::getBasePath();
SeasLog::setBasePath('/log/base_test');
$basePath_2 = SeasLog::getBasePath();
var_dump($basePath_1,$basePath_2);
/*
string(19) /log/seaslog-ciogao
string(14) /log/base_test
*/
$lastLogger_1 = SeasLog::getLastLogger();
SeasLog::setLogger('testModule/app1');
$lastLogger_2 = SeasLog::getLastLogger();
var_dump($lastLogger_1,$lastLogger_2);
/*
string(7) default
string(15) testModule/app1
*/
?>
See also ext/SeasLog on Github and SeasLog
Only Variable For Reference
[Since 1.4.6] - [ -P Functions/OnlyVariableForReference ] - [ Online docs ]
When a method is requesting an argument to be a reference, it cannot be called with a literal value.
The call must be made with a variable, or any assimilated data container : array, property or static property.
<?php
// This is not possible
foo(1,2);
// This is working
foo($a, $b);
function foo($a, &$b) {}
?>
Note that PHP may detect this error at linting time, if the method is defined after being called : at that point, PHP will only check the problem during execution. This is definitely the case for methods, compared to functions or static methods.
See also and Passing arguments by reference
Wrong Access Style to Property
[Since 1.4.9] - [ -P Classes/UndeclaredStaticProperty ] - [ Online docs ]
Use the right syntax when reaching for a property. Static properties use the :: operator, and non-static properties use -> .
Mistaking one of the other raise two different reactions from PHP : Access to undeclared static property is a fatal error, while PHP Notice: Accessing static property aa::$a as non static is a notice.
<?php
class a {
static public $a = 1;
function foo() {
echo self::$a; // right
echo $this->a; // WRONG
}
}
class b {
public $b = 1;
function foo() {
echo $this->$b; // right
echo b::$b; // WRONG
}
}
?>
This analysis reports both static properties with a `->` access, and non-static properties with a `::` access.
See also and Static Keyword
Invalid Pack Format
[Since 1.4.9] - [ -P Structures/InvalidPackFormat ] - [ Online docs ]
Some characters are invalid in a pack() format string.
pack() and unpack() accept the following format specifiers : aAhHcCsSnviIlLNVqQJPfgGdeExXZ .
unpack() also accepts a name after the format specifier and an optional quantifier.
All other situations is not a valid, and produces a warning : pack()
<?php
$binarydata = pack(nvc*, 0x1234, 0x5678, 65, 66);
// the first unsigned short is stored as 'first'. The next matches are names with numbers.
$res = unpack('nfirst/vc*', $binarydata);
?>
Check pack() documentation for format specifiers that were introduced in various PHP version, namely 7.0, 7.1 and 7.2.
See also pack and unpack
Repeated Interface
[Since 1.4.9] - [ -P Interfaces/RepeatedInterface ] - [ Online docs ]
A class should implements only once an interface. An interface can only extends once another interface. In both cases, parent classes or interfaces must be checked.
PHP accepts multiple times the same interface in the implements clause. In fact, it doesn't do anything beyond the first implement.
<?php
use i as j;
interface i {}
// Multiple ways to reference an interface
class foo implements i, \i, j {}
// This applies to interfaces too
interface bar extends i, \i, j {}
?>
This code may compile, but won't execute.
See also Object Interfaces and The Basics
Don't Read And Write In One Expression
[Since 1.4.9] - [ -P Structures/DontReadAndWriteInOneExpression ] - [ Online docs ]
Avoid giving value and using it at the same time, in one expression. This is an undefined behavior of PHP, and may change without warning.
One of those changes happens between PHP 7.2 and 7.3 :
<?php
$arr = [1];
$ref =& $arr[0];
var_dump($arr[0] + ($arr[0] = 2));
// PHP 7.2: int(4)
// PHP 7.3: int(3)
?>
See also and UPGRADING 7.3
Pack Format Inventory
[Since 1.5.0] - [ -P Type/Pack ] - [ Online docs ]
All format used in the code with pack() and unpack().
<?php
$binarydata = "\x04\x00\xa0\x00";
$array = unpack("cn", $binarydata);
$initial = pack("cn", ...$array);
?>
See also and `pack()
Printf Format Inventory
[Since 1.5.0] - [ -P Type/Printf ] - [ Online docs ]
All format used in the code with printf(), vprintf(), sprintf(), scanf() and fscanf().
<?php
// Display a number with 2 digits
echo printf("%'.2d\n", 123);
?>
ext/decimal
[Since 1.5.2] - [ -P Extensions/Extdecimal ] - [ Online docs ]
Extension php-decimal, by Rudi Theunissen .
This library provides a PHP extension that adds support for correctly-rounded, arbitrary-precision decimal floating point arithmetic. Applications that rely on accurate numbers (ie. money, measurements, or mathematics) can use Decimal instead of float or string to represent numerical values.
<?php
use Decimal\Decimal;
$op1 = new Decimal(0.1, 4);
$op2 = 0.123456789;
print_r($op1 + $op2);
use Decimal\Decimal;
/**
* @param int $n The factorial to calculate, ie. $n!
* @param int $p The precision to calculate the factorial to.
*
* @return Decimal
*/
function factorial(int $n, int $p = Decimal::DEFAULT_PRECISION): Decimal
{
return $n < 2 ? new Decimal($n, $p) : $n * factorial($n - 1, $p);
}
echo factorial(10000, 32);
?>
See also PHP Decimal and libmpdec
ext/psr
[Since 1.5.2] - [ -P Extensions/Extpsr ] - [ Online docs ]
Extension PSR : PHP Standards Recommendations.
This PHP extension provides the interfaces from the PSR standards as established by the PHP-FIG group. You can use interfaces provided by this extension in another extension easily - see this example.
Currently supported PSR :
- PSR-3 - `psr/http-message`
- PSR-11 - `psr/container`
- PSR-13 - `psr/link`
- PSR-15 - `psr/http-server`
- PSR-16 - `psr/simple-cache`
- PSR-17 - `psr/http-factory`
<?php
// Example from the tests, for Cache (PSR-6)
use Psr\Cache\CacheException;
class MyCacheException extends Exception implements CacheException {}
$ex = new MyCacheException('test');
var_dump($ex instanceof CacheException);
var_dump($ex instanceof Exception);
try {
throw $ex;
} catch( CacheException $e ) {
var_dump($e->getMessage());
}
?>
See also php-psr and PHP-FIG
Should Yield With Key
[Since 1.5.2] - [ -P Functions/ShouldYieldWithKey ] - [ Online docs ]
iterator_to_array() will overwrite generated values with the same key.
PHP generators are based on the yield keyword. They also delegate some generating to other methods, with yield from .
When delegating, yield from uses the keys that are generated with yield , and otherwise, it uses auto-generated index, starting with 0.
The trap is that each yield from reset the index generation and start again with 0. Coupled with iterator_to_array(), this means that the final generated array may lack some values, while a foreach() loop would yield all of them.
<?php
function g1() : Generator {
for ( $i = 0; $i < 4; $i++ ) { yield $i; }
}
function g2() : Generator {
for ( $i = 5; $i < 10; $i++ ) { yield $i; }
}
function aggregator() : Generator {
yield from g1();
yield from g2();
}
print_r(`iterator_to_array() <https://www.php.net/iterator_to_array>`_);
/*
Array
(
[0] => 6
[1] => 7
[2] => 8
[3] => 9
[4] => 4 // Note that 4 and 5 still appears
[5] => 5 // They are not overwritten by the second yield
)
*/
foreach ( aggregator() as $i ) {
print $i.PHP_EOL;
}
/*
0 // Foreach has no overlap and yield it all.
1
2
3
4
5
6
7
8
9
*/
?>
Thanks to Holger Woltersdorf for pointing this.
See also Generator syntax and Yielding values with keys
Useless Method Alias
[Since 1.5.6] - [ -P Traits/UselessAlias ] - [ Online docs ]
It is not possible to declare an alias of a method with the same name.
PHP reports that Trait method f has not been applied, because there are collisions with other trait methods on x , which is a way to say that the alias will be in conflict with the method name.
When the method is the only one bearing a name, and being imported, there is no need to alias it. When the method is imported in several traits, the keyword insteadof is available to solve the conflict.
<?php
trait t {
function h() {}
}
class x {
use t {
// This is possible
t::f as g;
// This is not possible, as the alias is in conflict with itself
// alias are case insensitive
t::f as f;
}
}
?>
This code lints but doesn't execute.
See also and Conflict resolution
ext/sdl
[Since 1.5.6] - [ -P Extensions/Extsdl ] - [ Online docs ]
Extensions ext/sdl.
Simple DirectMedia Layer (SDL) is a cross-platform software development library designed to provide a hardware abstraction layer for computer multimedia hardware components.
<?php
/**
* Example of how to change screen properties such as title, icon or state using the PHP-SDL extension.
*
* @author Santiago Lizardo <santiagolizardo@php.net>
*/
require 'common.php';
SDL_Init( SDL_INIT_VIDEO );
$screen = SDL_SetVideoMode( 640, 480, 16, SDL_HWSURFACE );
if( null == $screen )
{
fprintf( STDERR, 'Error: %s' . PHP_EOL, SDL_GetError() );
}
for( $i = 3; $i > 0; $i-- )
{
SDL_WM_SetCaption( Switching to fullscreen mode in $i seconds..., null );
SDL_Delay( 1000 );
}
SDL_WM_ToggleFullscreen( $screen );
SDL_Delay( 3000 );
SDL_WM_ToggleFullscreen( $screen );
SDL_WM_SetCaption( Back from fullscreen mode. Quitting in 2 seconds..., null );
SDL_Delay( 2000 );
SDL_FreeSurface( $screen );
SDL_Quit();
?>
See also phpsdl, Simple DirectMedia Layer and About SDL
ext/wasm
[Since 1.5.7] - [ -P Extensions/Extwasm ] - [ Online docs ]
Extension WASM.
The goal of the project is to be able to run WebAssembly binaries from PHP directly. So much fun coming!
From the php-ext-wasm documentation :
<?php
//There is a toy program in examples/simple.rs, written in Rust (or any other language that compiles to WASM):
// Stored in file __DIR__ . '/simple.wasm'
/*
#[no_mangle]
pub extern C fn sum(x: i32, y: i32) -> i32 {
x + y
}
*/
$instance = new WASM\Instance(__DIR__ . '/simple.wasm');
var_dump(
$instance->sum(5, 37) // 42!
);
?>
See also and php-ext-wasm
Method Could Be Static
[Since 1.5.7] - [ -P Classes/CouldBeStatic ] - [ Online docs ]
A method that doesn't make any usage of $this could be turned into a static method.
While static methods are usually harder to handle, recognizing the static status is a first step before turning the method into a standalone function.
<?php
class foo {
static $property = 1;
// legit static method
static function staticMethod() {
return self::$property;
}
// This is not using $this, and could be static
function nonStaticMethod() {
return self::$property;
}
// This is not using $this nor self, could be a standalone function
function nonStaticMethod() {
return self::$property;
}
}
?>
Path lists
[Since 1.5.8] - [ -P Type/Path ] - [ Online docs ]
List of all paths that were found in the code.
Path are identified with this regex : ^(.*/)([^/]*)\.\w+$ . In particular, the directory delimiter is / : Windows delimiter \ are not detected.
<?php
// the first argument is recognized as an URL
fopen('/tmp/my/file.txt', 'r+');
// the string argument is recognized as an URL
$source = 'https://www.other-example.com/';
?>
URL are ignored when the protocol is present in the literal : http://www.example.com is not mistaken with a file.
See also Dir predefined constants and Supported Protocols and Wrappers
Possible Missing Subpattern
[Since 1.6.1] - [ -P Php/MissingSubpattern ] - [ Online docs ]
When capturing subpatterns are the last ones in a regex, PHP doesn't fill their spot in the resulting array. This leads to a possible missing index in the result array.
<?php
// displays a partial array, from 0 to 1
preg_match('/(a)(b)?/', 'adc', $r);
print_r($r);
/*
Array
(
[0] => a
[1] => a
)
*/
// displays a full array, from 0 to 2
preg_match('/(a)(b)?/', 'abc', $r);
print_r($r);
/*
Array
(
[0] => ab
[1] => a
[2] => b
)
*/
// double 'b' when it is found
print preg_replace(',^a(b)?,', './$1$1', 'abc'); // prints ./abbc
print preg_replace(',^a(b)?,', './$1$1', 'adc'); // prints ./dc
?>
The same applies to preg_replace() : the pattern may match the string, but no value is available is the corresponding sub-pattern.
In PHP 7.4, a new option was added : PREG_UNMATCHED_AS_NULL , which always provides a value for the subpatterns.
See also Bug #73948 Preg_match_all should return NULLs on trailing optional capture groups. and Bug #50887 preg_match , last optional sub-patterns ignored when empty
Assign And Compare
[Since 1.6.3] - [ -P Structures/AssigneAndCompare ] - [ Online docs ]
Assignation has a lower precedence than comparison. As such, the assignation always happens after the comparison. This leads to the comparison being stored in the variable, and not the value being compared.
<?php
if ($id = strpos($string, $needle) !== false) {
// $id now contains a boolean (true or false), but not the position of the $needle.
}
// probably valid comparison, as $found will end up being a boolean
if ($found = strpos($string, $needle) === false) {
doSomething();
}
// always valid comparison, with parenthesis
if (($id = strpos($string, $needle)) !== false) {
// $id now contains a boolean (true or false), but not the position of the $needle.
}
// Being a lone instruction, this is always valid : there is no double usage with if condition
$isFound = strpos($string, $needle) !== false;
?>
See also and Operator Precedence
Typed Property Usage
[Since 1.6.2] - [ -P Php/TypedPropertyUsage ] - [ Online docs ]
PHP properties may be typed. Since PHP 7.4, it is possible to type properties, just like arguments and return values.
<?php
class User {
public int $id;
public string $name;
public function __construct(int $id, string $name) {
$this->id = $id;
$this->name = $name;
}
}
?>
See also Typed Properties 2.0 and Typed Properties in PHP 7.4
Variable Is Not A Condition
[Since 1.6.5] - [ -P Structures/NoVariableIsACondition ] - [ Online docs ]
Avoid using a lone variable as a condition. It is recommended to use a comparative value, or one of the filtering function, such as isset(), empty().
Using the raw variable as a condition blurs the difference between an undefined variable and an empty value. By using an explicit comparison or validation function, it is easier to understand what the variable stands for.
<?php
if (isset($error)) {
echo 'Found one error : '.$error!;
}
//
if ($errors) {
print count($errors).' errors found : '.join('', $errors).PHP_EOL;
echo 'Not found';
}
?>
Thanks to the PMB team for the inspiration.
ext/weakref
[Since 1.6.5] - [ -P Extensions/Extweakref ] - [ Online docs ]
Weak References for PHP.
Weak references provide a non-intrusive gateway to ephemeral objects. Unlike normal (strong) references, weak references do not prevent the garbage collector from freeing that object. For this reason, an object may be destroyed even though a weak reference to that object still exists. In such conditions, the weak reference seamlessly becomes invalid.
<?php
class MyClass {
public function __destruct() {
echo Destroying object!\n;
}
}
$o1 = new MyClass;
$r1 = new WeakRef($o1);
if ($r1->valid()) {
echo Object still exists!\n;
var_dump($r1->get());
} else {
echo Object is dead!\n;
}
unset($o1);
if ($r1->valid()) {
echo Object still exists!\n;
var_dump($r1->get());
} else {
echo Object is dead!\n;
}
?>
See also Weak references and PECL extension that implements weak references and weak maps in PHP
ext/pcov
[Since 1.6.5] - [ -P Extensions/Extpcov ] - [ Online docs ]
CodeCoverage compatible driver for PHP.
A self contained CodeCoverage compatible driver for PHP7
<?php
\pcov\start();
$d = [];
for ($i = 0; $i < 10; $i++) {
$d[] = $i * 42;
}
\pcov\stop();
var_dump(\pcov\collect());
?>
See also and PCOV
Insufficient Typehint
[Since 1.6.6] - [ -P Functions/InsufficientTypehint ] - [ Online docs ]
An argument is typehinted, but it actually calls methods that are not listed in the interface.
Classes may be implementing more methods than the one that are listed in the interface they also implements. This means that filtering objects with a typehint, but calling other methods will be solved at execution time : if the method is available, it will be used; if it is not, a fatal error is reported.
<?php
class x implements i {
function methodI() {}
function notInI() {}
}
interface i {
function methodI();
}
function foo(i $x) {
$x->methodI(); // this call is valid
$x->notInI(); // this call is not garanteed
}
?>
Inspired by discussion with Brandon Savage.
See also and Interface segregation principle
Constant Dynamic Creation
[Since 1.6.7] - [ -P Constants/DynamicCreation ] - [ Online docs ]
Registering constant with dynamic values. Dynamic values include values read in external sources (files, databases, remote API, ... ), random sources (time, rand(), ...)
Dynamic constants are not possible with the const keyword, though static constant expression allows for a good range of combinations, including conditions.
<?php
$a = range(0, 4);
foreach($array as $i) {
define(A$i, $i);
define(N$i, true);
}
define(C, 5);
?>
See also and PHP Constants
PHP 8.0 Removed Functions
[Since 1.6.8] - [ -P Php/Php80RemovedFunctions ] - [ Online docs ]
The following PHP native functions were deprecated in PHP 8.0, and will be removed in PHP 9.0.
- image2wbmp()
- png2wbmp()
- jpeg2wbmp()
- ldap_sort()
- hebrevc()
- convert_cyr_string()
- ezmlm_hash()
- money_format()
- get_magic_quotes_gpc()
- get_magic_quotes_gpc_runtime()
- create_function()
- each()
- read_exif_data()
- gmp_random()
- fgetss()
- restore_include_path()
- gzgetss()
- mbregex_encoding()
- mbereg()
- mberegi()
- mbereg_replace()
- mberegi_replace()
- mbsplit()
- mbereg_match()
- mbereg_search()
- mbereg_search_pos()
- mbereg_search_regs()
- mbereg_search_init()
- mbereg_search_getregs()
- mbereg_search_getpos()
- mbereg_search_setpos()
See also and Backward Incompatible Changes
PHP 8.0 Removed Constants
[Since 1.6.8] - [ -P Php/Php80RemovedConstant ] - [ Online docs ]
The following PHP native constants were removed in PHP 8.0.
- INTL_IDNA_VARIANT_2003 (See Deprecate and remove INTL_IDNA_VARIANT_2003)
- MB_OVERLOAD_MAIL
- MB_OVERLOAD_STRING
- MB_OVERLOAD_REGEX
An OOP Factory
[Since 1.6.7] - [ -P Patterns/Factory ] - [ Online docs ]
A method or function that implements a factory. A factory is a class that handles the creation of an object, based on parameters. The factory hides the logic that leads to the creation of the object.
<?php
class AutomobileFactory {
public static function create($make, $model) {
$className = \\Automaker\\Brand\\$make;
return new $className($model);
}
}
// The factory is able to build any car, based on their
$fuego = AutomobileFactory::create('Renault', 'Fuego');
print_r($fuego->getMakeAndModel()); // outputs Renault Fuego
?>
See also Factory (object-oriented programming) and Factory
Typehint Must Be Returned
[Since 1.6.9] - [ -P Functions/TypehintMustBeReturned ] - [ Online docs ]
When using a typehint for a method, it is compulsory to use a at least one return in the method's body. This is true for nullable typehint too : return alone won't be sufficient.
When the method contains a return expression, PHP will not lint unless the return expression has a value. Any value will do, and it will actually checked at execution time.
When the method contains no return expression, PHP will only check this at execution time.
There is no need for a return expression when the method throws an expression, triggers an error or triggers an assertion. Even in case of inheritance or implementation, the return type may be replaced by `never`.
<?php
// The function returns a value (here, correct object)
function foo() : Bar { return new Bar(); }
// The function should at least, return a value
function foo() : Bar { }
// The function should at least, return a value : Null or an object. Void, here, is not acceptable.
function foo() : ?Bar { return; }
?>
See also Return Type Declaration and Type hint in PHP function parameters and return values
Clone With Non-Object
[Since 1.7.0] - [ -P Classes/CloneWithNonObject ] - [ Online docs ]
The clone keyword must be used on variables, properties or results from a function or method call.
clone cannot be used with constants or literals.
<?php
class x { }
$x = new x();
// Valid clone
$y = clone $x;
// Invalid clone
$y = clone x;
?>
Cloning a non-object lint but won't execute.
See also and Object cloning
Check On __Call Usage
[Since 1.7.2] - [ -P Classes/CheckOnCallUsage ] - [ Online docs ]
When using the magic methods __call() and __staticcall(), make sure the method exists before calling it.
If the method doesn't exists, then the same method will be called again, leading to the same failure. Finally, it will crash PHP.
<?php
class safeCall {
function __class($name, $args) {
// unsafe call, no checks
if (method_exists($this, $name)) {
$this->$name(...$args);
}
}
}
class unsafeCall {
function __class($name, $args) {
// unsafe call, no checks
$this->$name(...$args);
}
}
?>
See also Method overloading and Magical PHP: __call
PHP Overridden Function
[Since 1.7.6] - [ -P Php/OveriddenFunction ] - [ Online docs ]
It is possible to declare and use a function with the same name as a PHP native, in a namespace.
Within the declaration namespace, it is easy to confuse the local version and the global version, unless the function has been prefixed with \ .
<?php
namespace A {
use function A\dirname as split;
function dirname($a, $b) { return __FUNCTION__; }
echo dirname('/a/b/c');
echo split('a', 'b');
echo \dirname('/a/b/c');
}
?>
When a piece of code use overridden function, any newcomer may be confused by the usage of classic PHP native function in surprising situations.
It is recommended to avoid redeclare PHP native function in namespaces.
ext/svm
[Since 1.7.8] - [ -P Extensions/Extsvm ] - [ Online docs ]
Extension SVM .
SVM is in interface with the libsvm , from . libsvm is a library for Support Vector Machines, a classification tool for machine learning.
<?php
$data = array(
array(-1, 1 => 0.43, 3 => 0.12, 9284 => 0.2),
array(1, 1 => 0.22, 5 => 0.01, 94 => 0.11),
);
$svm = new SVM();
$model = $svm->train($data);
$data = array(1 => 0.43, 3 => 0.12, 9284 => 0.2);
$result = $model->predict($data);
var_dump($result);
$model->save('model.svm');
?>
See also SVM, LIBSVM -- A Library for Support Vector Machines, ext/svm and ianbarber/php-svm
Avoid option arrays in constructors
[Since 1.7.9] - [ -P Classes/AvoidOptionArrays ] - [ Online docs ]
Avoid option arrays in constructors. Use one parameter per injected element.
<?php
class Foo {
// Distinct arguments, all typehinted if possible
function __construct(A $a, B $b, C $c, D $d) {
$this->a = $a;
$this->b = $b;
$this->c = $c;
$this->d = $d;
}
}
class Bar {
// One argument, spread over several properties
function __construct(array $options) {
$this->a = $options['a'];
$this->b = $options['b'];
$this->c = $options['c'];
$this->d = $options['d'];
}
}
?>
See also Avoid option arrays in constructors and PHP RFC: Named Arguments (Type-safe and documented options)
ext/ffi
[Since 1.7.9] - [ -P Extensions/Extffi ] - [ Online docs ]
Extension FFI : Foreign Function Interface .
This extension allows the loading of shared libraries (.DLL or .so), calling of C functions and accessing of C data structures in pure PHP, without having to have deep knowledge of the Zend extension API, and without having to learn a third “intermediate” language. The public API is implemented as a single class FFI with several static methods (some of them may be called dynamically), and overloaded object methods, which perform the actual interaction with C data.
<?php
//Example : Calling a function from shared library
// create FFI object, loading libc and exporting function `printf() <https://www.php.net/printf>`_
$ffi = FFI::cdef(
"int printf(const char *format, ...);", // this is a regular C declaration
"libc.so.6");
// call C's `printf() <https://www.php.net/printf>`_
$ffi->printf("Hello %s!\n", "world");
?>
See also ext/ffi and A PHP Compiler, aka The FFI Rabbit Hole
ext/password
[Since 0.8.4] - [ -P Extensions/Extpassword ] - [ Online docs ]
Extension password.
The password hashing API provides an easy to use wrapper around crypt() and some other password hashing algorithms, to make it easy to create and manage passwords in a secure manner.
<?php
// See the `password_hash() <https://www.php.net/password_hash>`_ example to see where this came from.
$hash = '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';
if (password_verify('rasmuslerdorf', $hash)) {
echo 'Password is valid!';
} else {
echo 'Invalid password.';
}
?>
See also Password Hashing and crypt man page
ext/zend_monitor
[Since 1.7.9] - [ -P Extensions/Extzendmonitor ] - [ Online docs ]
Extension zend_monitor .
The Zend Monitor component is integrated into the runtime environment and serves as an alerting and collection mechanism for early detection of PHP script problems.
<?php
zend_monitor_pass_error();
?>
See also Zend Monitor - PHP API and `Zend Monitor `
ext/uuid
[Since 1.7.9] - [ -P Extensions/Extuuid ] - [ Online docs ]
Extension UUID . A universally unique identifier (UUID) is a 128-bit number used to identify information in computer systems.
An interface to the libuuid system library. The libuuid library is used to generate unique identifiers for objects that may be accessible beyond the local system. The Linux implementation was created to uniquely identify ext2 filesystems created by a machine. This library generates UUIDs compatible with those created by the Open Software Foundation (OSF) Distributed Computing Environment (DCE) utility uuidgen.
<?php
// example from the test suitee of the extension.
// check basic format of generated UUIDs
$uuid = uuid_create();
if (preg_match("/[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{12}/", $uuid)) {
echo "basic format ok\n";
} else {
echo "basic UUID format check failed, generated UUID was $uuid\n";
}
?>
See also libuuid and ext/uuid
Already Parents Trait
[Since 1.8.0] - [ -P Traits/AlreadyParentsTrait ] - [ Online docs ]
Trait is already used a parent's class or trait. There is no use to include it a second time.
<?php
trait ta {
use tb;
}
trait t1 {
use ta;
use tb; // also used by ta
}
class b {
use t1; // also required by class c
use ta; // also required by trait t1
}
class c extends b {
use t1;
}
?>
See also and Traits
Trait Not Found
[Since 1.7.9] - [ -P Traits/TraitNotFound ] - [ Online docs ]
A unknown trait is mentioned in the use expression.
The used traits all exist, but in the configuration block, some unmentioned trait is called.
Be aware that the traits used in any configuration block may originate in any use expression. PHP will check the configuration block at instantiation only, and after compiling : at that moment, it will know all the used traits across the class.
<?php
class x {
// c is not a used trait
use a, b { c::d insteadof e;}
// e is a used trait, even if is not in the use above.
use e;
}
?>
See also and Traits
Casting Ternary
[Since 1.8.0] - [ -P Structures/CastingTernary ] - [ Online docs ]
Type casting has a precedence over ternary operator, and is applied first. When this happens, the condition is cast, although it is often useless as PHP will do it if needed.
This applies to the ternary operator, the coalesce operator ?: and the null-coalesce operator ??.
<?php
$a = (string) $b ? 3 : 4;
$a = (string) $b ?: 4;
$a = (string) $b ?? 4;
?>
The last example generates first an error `Undefined variable: b`, since $b is first cast to a string. The result is then an empty string, which leads to an empty string to be stored into $a. Multiple errors cascade.
See also and Operators Precedence
Concat Empty String
[Since 1.8.0] - [ -P Structures/ConcatEmpty ] - [ Online docs ]
Using a concatenation to make a value a string should be replaced with a type cast.
Type cast to a string is done with (string) operator. There is also the function strval(), although it is less recommended.
<?php
$a = 3;
// explicite way to cast a value
$b = (string) $a; // $b is a string with the content 3
// Wrong way to cast a value
$c = $a . ''; // $c is a string with the content 3
$c = '' . $a; // $c is a string with the content 3
$a .= ''; // $a is a string with the content 3
// Wrong way to cast a value
$c = $a . '' . $b; // This is not reported. The empty string is useless, but not meant to type cast
?>
See also Type Casting and
PHP Type Casting.
Concat And Addition
[Since 1.8.0] - [ -P Php/ConcatAndAddition ] - [ Online docs ]
Precedence between addition and concatenation has changed. In PHP 7.4, addition has precedence, and before, addition and concatenation had the same precedence.
From the RFC : Currently the precedence of '.', '+' and '-' operators are equal. Any combination of these operators are simply evaluated left-to-right .
This is counter-intuitive though: you rarely want to add or subtract concatenated strings which in general are not numbers. However, given PHP's capability of seamlessly converting an integer to a string, concatenation of these values is desired.
<?php
// Extracted from the RFC
echo sum: . $a + $b;
// current behavior: evaluated left-to-right
echo (sum: . $a) + $b;
// desired behavior: addition and subtraction have a higher precendence
echo sum : . ($a + $b);
?>
This analysis reports any addition and concatenation that are mixed, without parenthesis. Addition also means substraction here, aka using `+` or `-`.
The same applies to bitshift operations, << and >>``. There is no RFC for this change.
See also and Change the precedence of the concatenation operator
No Append On Source
[Since 1.8.2] - [ -P Structures/NoAppendOnSource ] - [ Online docs ]
Do not append new elements to an array in a foreach loop. Since PHP 7.0, the array is still used as a source, and will be augmented, and used again.
<?php
// Relying on the initial copy
$a = [1];
$initial = $a;
foreach($initial as $v) {
$a[] = $v + 1;
}
// Keep new results aside
$a = [1];
$tmp = [];
foreach($a as $v) {
$tmp[] = $v + 1;
}
$a = array_merge($a, $tmp);
unset($tmp);
// Example, courtesy of Frederic Bouchery
// This is an infinite loop
$a = [1];
foreach($a as $v) {
$a[] = $v + 1;
}
?>
Thanks to Frederic Bouchery for the reminder.
See also foreach and What will this code return? #PHP
Memoize MagicCall
[Since 1.8.3] - [ -P Performances/MemoizeMagicCall ] - [ Online docs ]
Cache calls to magic methods in local variable. Local cache is faster than calling again the magic method as soon as the second call, provided that the value hasn't changed.
__get is slower, as it turns a simple member access into a full method call.
<?php
class x {
private $values = array();
function __get($name) {
return $this->values[$name];
}
// more code to set values to this class
}
function foo(x $b) {
$a = $b->a;
$c = $b->c;
$d = $c; // using local cache, no new access to $b->__get($name)
$e = $b->a; // Second access to $b->a, through __get
}
function bar(x $b) {
$a = $b->a;
$c = $b->c;
$b->bar2(); // this changes $b->a and $b->c, but we don't see it
$d = $b->c;
$e = $b->a; // Second access to $b->a, through __get
}
?>
The caching is not possible if the processing of the object changes the value of the property.
See also __get performance questions with PHP, Classes/MakeMagicConcrete and Benchmarking magic
Unused Class Constant
[Since 1.8.4] - [ -P Classes/UnusedConstant ] - [ Online docs ]
The class constant is unused. Consider removing it or using it.
Class constants may be used in expressions, in static expressions, when building other constants, or in default values.
<?php
class foo {
public const UNUSED = 1; // No mention in the code
private const USED = 2; // used constant
function bar() {
echo self::USED;
}
}
?>
Infinite Recursion
[Since 1.8.6] - [ -P Structures/InfiniteRecursion ] - [ Online docs ]
A method is calling itself, with unchanged arguments. This might repeat indefinitely.
This applies to recursive functions without any condition. This also applies to function which inject the incoming arguments, without modifications.
<?php
function foo($a, $b) {
if ($a > 10) {
return;
}
foo($a, $b);
}
function foo2($a, $b) {
++$a; // $a is modified
if ($a > 10) {
return;
}
foo2($a, $b);
}
?>
Null Or Boolean Arrays
[Since 1.8.6] - [ -P Arrays/NullBoolean ] - [ Online docs ]
Null and booleans are valid PHP array base. Yet, they only produces null values. They also did not emits any warning until PHP 7.4.
This analysis has been upgraded to cover int and float types too.
<?php
// outputs NULL
var_dump(null[0]);
const MY_CONSTANT = true;
// outputs NULL
var_dump(MY_CONSTANT[10]);
?>
See also and Null and True
Dependant Abstract Classes
[Since 1.8.6] - [ -P Classes/DependantAbstractClass ] - [ Online docs ]
Abstract classes should be autonomous. It is recommended to avoid depending on methods, constant or properties that should be made available in inheriting classes, without explicitly abstracting them.
The following abstract classes make usage of constant, methods and properties, static or not, that are not defined in the class. This means the inheriting classes must provide those constants, methods and properties, but there is no way to enforce this.
This may also lead to dead code : when the abstract class is removed, the host class have unused properties and methods.
<?php
// autonomous abstract class : all it needs is within the class
abstract class c {
private $p = 0;
function foo() {
return ++$this->p;
}
}
// dependant abstract class : the inheriting classes needs to provide some properties or methods
abstract class c2 {
function foo() {
// $p must be provided by the extending class
return ++$this->p;
}
}
class c3 extends c2 {
private $p = 0;
}
?>
See also and Traits/DependantTrait
Wrong Type Returned
[Since 1.8.7] - [ -P Functions/WrongReturnedType ] - [ Online docs ]
The returned value is not compatible with the specified return type.
<?php
// classic error
function bar() : int {
return 'A';
}
// classic static error
const B = 2;
function bar() : string {
return B;
}
// undecideable error
function bar($c) : string {
return $c;
}
// PHP lint this, but won't execute it
function foo() : void {
// No return at all
}
?>
See also Returning values, Void Return Type, Functions/MismatchTypeAndDefault and Classes/WrongTypedPropertyInit
Overwritten Source And Value
[Since 1.8.9] - [ -P Structures/ForeachSourceValue ] - [ Online docs ]
In a foreach(), it is best to keep source and values distinct. Otherwise, they overwrite each other.
Since PHP 7.0, PHP makes a copy of the original source, then works on it. This makes possible to use the same name for the source and the values.
<?php
// displays 0-1-2-3-3
$array = range(0, 3);
foreach($array as $array) {
print $array . '-';
}
print_r($array);
/* displays 0-1-2-3-Array
(
[0] => 0
[1] => 1
[2] => 2
[3] => 3
)
*/
$array = range(0, 3);
foreach($array as $v) {
print $v . '-';
}
print_r($array);
?>
When the source is used as the value, the elements in the array are successively assigned to itself. After the loop, the original array has been replaced by its last element.
The same applies to the index, or to any variable in a list() structure, used in a foreach().
Avoid mb_dectect_encoding()
[Since 1.8.9] - [ -P Php/AvoidMbDectectEncoding ] - [ Online docs ]
mb_dectect_encoding() is bad at guessing encoding.
For example, UTF-8 and ISO-8859-1 share some common characters : when a string is build with them it is impossible to differentiate the actual encoding.
<?php
$encoding = mb_encoding_detect($_GET['name']);
?>
See also mb_encoding_detect, PHP vs. The Developer: Encoding Character Sets and DPC2019: Of representation and interpretation: A unified theory - Arnout Boks
array_key_exists() Works On Arrays
[Since 1.9.0] - [ -P Php/ArrayKeyExistsWithObjects ] - [ Online docs ]
array_key_exists() requires arrays as second argument. Until PHP 7.4, objects were also allowed, yet it is now deprecated.
<?php
// Valid way to check for key
$array = ['a' => 1];
var_dump(array_key_exists('a', $array))
// Deprecated since PHP 7.4
$object = new Stdclass();
$object->a = 1;
var_dump(array_key_exists('a', $object))
?>
See also `array_key_exists() with objects
Numeric Literal Separator
[Since 1.9.0] - [ -P Php/IntegerSeparatorUsage ] - [ Online docs ]
Integer and floats may be written with internal underscores. This way, it is possible to separate large number into smaller groups, and make them more readable.
Numeric Literal Separators were introduced in PHP 7.4 and are not backward compatible.
<?php
$a = 1_000_000_000; // A billion
$a = 1000000000; // A billion too...
$b = 107_925_284.88; // 6 light minute to kilometers = 107925284.88 kilometers
$b = 107925284.88; // Same as above
?>
See also and PHP RFC: Numeric Literal Separator
Class Without Parent
[Since 1.9.0] - [ -P Classes/NoParent ] - [ Online docs ]
Classes should not refer to parent when it is not extending another class.
In PHP 7.4, it is a Deprecated warning. In PHP 7.3, it was a Fatal error, when the code was eventually executed. In PHP 8.0, PHP detects this error at compile time, except for parent keyword in a closure.
parent usage in trait is detected. It is only reported when the trait is used inside a class without parent, as the trait may also be used in another class, which has a parent.
<?php
class x {
function foo() {
parent::foo();
}
}
?>
Scalar Are Not Arrays
[Since 1.9.0] - [ -P Php/ScalarAreNotArrays ] - [ Online docs ]
It is wrong to use a scalar as an array, a Warning is emitted. PHP 7.4 emits a Warning in such situations.
<?php
// Here, $x may be null, and in that case, the echo will fail.
function foo(?A $x) {
echo $x[2];
}
?>
Typehinted argument with a scalar are reported by this analysis. Also, nullable arguments, both with typehint and return type hint.
See also and E_WARNING for invalid container read array-access
array_merge() And Variadic
[Since 1.9.2] - [ -P Structures/ArrayMergeAndVariadic ] - [ Online docs ]
Always check value in variadic before using it with array_merge() and array_merge_recursive().
Before PHP 7.4, array_merge() and array_merge_recursive() would complain when no argument was provided. As such, using the spread operator `...` on an empty array() would yield no argument, and an error.
<?php
$b = array_merge(...$x);
?>
Implode() Arguments Order
[Since 1.9.2] - [ -P Structures/ImplodeArgsOrder ] - [ Online docs ]
implode() used to accept two signatures, but is only recommending one. Both types orders of string then array, and array then string have been possible until PHP 7.4.
In PHP 7.4, the order array then string is deprecated, and emits a warning. It will be removed in PHP 8.0.
<?php
$glue = ',';
$pieces = range(0, 4);
// documented argument order
$s = implode($glue, $pieces);
// Pre 7.4 argument order
$s = implode($pieces, $glue);
// both produces 0,1,2,3,4
?>
See also and implode()
PHP 7.4 Removed Directives
[Since 1.9.3] - [ -P Php/Php74RemovedDirective ] - [ Online docs ]
List of directives that are removed in PHP 7.4.
+ allow_url_include
See also and Deprecation allow_url_include
strip_tags() Skips Closed Tag
[Since 1.9.3] - [ -P Structures/StripTagsSkipsClosedTag ] - [ Online docs ]
strip_tags() skips non-self closing tags. This means that tags such as
will be ignored from the second argument of the function.
<?php
$input = 'a<br />';
// Displays 'a' and clean the tag
echo strip_tags($input, '<br>');
// Displays 'a<br />' and skips the allowed tag
echo strip_tags($input, '<br/>');
?>
See also and strip_tags
No Spread For Hash
[Since 1.9.3] - [ -P Arrays/NoSpreadForHash ] - [ Online docs ]
The spread operator ... only works on integer-indexed arrays.
<?php
// This is valid, as -33 is cast to integer by PHP automagically
var_dump(...[1,-33 => 2, 3]);
// This is not valid
var_dump(...[1,C => 2, 3]);
?>
See also and Variable-length argument lists
Use Covariance
[Since 1.9.3] - [ -P Php/UseCovariance ] - [ Online docs ]
Covariance is compatible return typehint. A child class may return an object of a child class of the return type of its parent's method.
Since a children class may return a children class of the return type, the evolution is in the same order.
Covariance is a PHP 7.4 feature. Covariance is distinct from argument contravariance.
<?php
class X {
function m(Y $z): X {}
}
// m is overwriting the parent's method.
// The return type is different.
// The return type is compatible, as Y is also a sub-class of X.
class Y extends X {
function m(X $z): Y {}
}
?>
See also Covariant Returns and Contravariant Parameters and `Php/UseContravariance`_
Use Contravariance
[Since 1.9.3] - [ -P Php/UseContravariance ] - [ Online docs ]
Contravariance is compatible argument typehint. A child class may accept an object of a parent class of the argument type of its parent's method.
Since a children class may accept a parent class of the argument type, the evolution is in opposite order.
Contravariance is a PHP 7.4 feature. Contravariance is distinct from return type covariance.
<?php
class X {
function m(Y $z): X {}
}
// m is overwriting the parent's method.
// The return type is different.
// The return type is compatible, as Y is also a sub-class of X.
class Y extends X {
function m(X $z): Y {}
}
?>
See also Covariant Returns and Contravariant Parameters and `Php/UseCovariance`
Use Arrow Functions
[Since 1.9.4] - [ -P Functions/UseArrowFunctions ] - [ Online docs ]
Arrow functions are closures that require less code to write.
Arrow functions were introduced in PHP 7.4. They added the reserved keyword fn . s
<?php
array_map(fn(A $b): int => $b->c, $array);
function array_values_from_keys($arr, $keys) {
return array_map(fn($x) => $arr[$x], $keys);
}
?>
See also RFC : Arrow functions and Arrow functions in PHP
Max Level Of Nesting
[Since 1.9.3] - [ -P Structures/MaxLevelOfIdentation ] - [ Online docs ]
Avoid nesting structures too deep, as it hurts readability.
Nesting structures are : if/then, switch, for, foreach, while, do...while. Ternary operator, try/catch are not considered a nesting structures.
Closures, and more generally, functions definitions are counted separatedly.
This analysis checks for 4 levels of nesting, by default. This may be changed by configuration.
<?php
// 5 levels of indentation
function foo() {
if (1) {
if (2) {
if (3) {
if (4) {
if (5) {
51;
} else {
5;
}
} else {
4;
}
} else {
3;
}
} else {
2;
}
} else {
1;
}
}
// 2 levels of indentation
function foo() {
if (1) {
if (2) {
// 3 levels of indentation
return function () {
if (3) {
if (4) {
if (5) {
51;
} else {
5;
}
} else {
4;
}
} else {
3;
}
}
} else {
2;
}
} else {
1;
}
}
?>
See also and `Indentation and Spacing in PHP
Spread Operator For Array
[Since 1.9.4] - [ -P Php/SpreadOperatorForArray ] - [ Online docs ]
The variadic operator may be used with arrays. This has been introduced in PHP 7.4.
list() is not allowed to use this operator, as list() expected variables, not values.
<?php
$array = [1, 2, 3];
$extended_array = [...$array, 4, 5, 6];
// invalid syntax
[...$a] = [1,2,3];
?>
See also and Spread Operator in Array Expression
Nested Ternary Without Parenthesis
[Since 1.9.4] - [ -P Php/NestedTernaryWithoutParenthesis ] - [ Online docs ]
It is not allowed to nest ternary operator within itself, without parenthesis. This has been implemented in PHP 7.4.
The reason behind this feature is to keep the code expressive. See the Warning message for more explanations
<?php
$a ? 1 : ($b ? 2 : 3);
// Still valid, as not ambiguous
$a ? $b ? 1 : 2 : 3;
// Produces a warning
//Unparenthesized `a ? b : c ? d : e` is deprecated. Use either `(a ? b : c) ? d : e` or `a ? b : (c ? d : e)`
$a ? 1 : $b ? 2 : 3;
?>
See also and PHP RFC: Deprecate left-associative ternary operator
Should Use Explode Args
[Since 1.9.4] - [ -P Structures/ShouldUseExplodeArgs ] - [ Online docs ]
explode() has a third argument, which limits the amount of exploded elements. With it, it is possible to collect only the first elements, or drop the last ones.
<?php
$exploded = explode(DELIMITER, $string);
// use explode(DELIMITER, $string, -1);
array_pop($exploded);
// use explode(DELIMITER, $string, -2);
$c = array_slice($exploded, 0, -2);
// with `explode() <https://www.php.net/explode>`_'s third argument :
list($a, $b) = explode(DELIMITER, $string, 2);
// with list() omitted arguments
list($a, $b, ) = explode(DELIMITER, $string);
?>
See also and explode
Use array_slice()
[Since 1.9.5] - [ -P Performances/UseArraySlice ] - [ Online docs ]
Array_slice() is de equivalent of substr() for arrays.
array_splice() is also available, to remove a portion of array inside the array, not at the ends. This has no simple equivalent for strings.
<?php
$array = range(0, 9);
// Extract the 5 first elements
print_r(array_slice($array, 0, 5));
// Extract the 4 last elements
print_r(array_slice($array, -4));
// Extract the 2 central elements : 4 and 5
print_r(array_splice($array, 4, 2));
// slow way to remove the last elementst of an array
for($i = 0; $i < 4) {
array_pop($array);
}
?>
See also array_slice and array_splice
Too Many Array Dimensions
[Since 1.9.4] - [ -P Arrays/TooManyDimensions ] - [ Online docs ]
This analysis reports when arrays have too many dimensions. This happens when arrays are too deeply nested inside other arrays.
<?php
$a = array(); // level 1;
$a[1] = array(); // level 2
$a[1][2] = array(); // level 3 : still valid by default
$a[1][2][3] = array(); // level 4
?>
PHP has no nesting limit, and accepts any number of of dimensions. This is usually very memory hungry, and could be better replaced with classes.
The default threshold for this rule is 3 (see examples above).
Coalesce And Concat
[Since 1.9.4] - [ -P Structures/CoalesceAndConcat ] - [ Online docs ]
The concatenation operator dot has precedence over the coalesce operator ??.
<?php
// Parenthesis are the right solution when in doubt
echo a . ($b ?? 'd') . $e;
// 'a' . $b is evaluated first, leading ot a useless ?? operator
'a' . $b ?? $c;
// 'd' . 'e' is evaluated first, leading to $b OR 'de'.
echo $b ?? 'd' . 'e';
?>
Comparison Is Always The Same
[Since 1.9.4] - [ -P Structures/AlwaysFalse ] - [ Online docs ]
Based on the incoming type of arguments, the comparison always yields the same value. The whole condition might be useless.
<?php
function foo(array $a) {
// This will always fail
if ($a === 1) {
} elseif (is_int($a)) {
}
// This will always succeed
if ($a !== null) {
} elseif (is_null($a)) {
}
}
?>
Incompatible Signature Methods With Covariance
[Since 1.3.3] - [ -P Classes/IncompatibleSignature74 ] - [ Online docs ]
Methods should have the compatible signature when being overwritten.
The same signatures means the children class must have :
+ the same name
+ the same visibility or less restrictive
+ the same contravariant typehint or removed
+ the same covariant return typehint or removed
+ the same default value or removed
+ a reference like its parent
This problem emits a fatal error, for abstract methods, or a warning error, for normal methods. Yet, it is difficult to lint, because classes are often stored in different files. As such, PHP do lint each file independently, as unknown parent classes are not checked if not present. Yet, when executing the code, PHP lint the actual code and may encounter a fatal error.
<?php
class a {
public function foo($a = 1) {}
}
class ab extends a {
// foo is overloaded and now includes a default value for $a
public function foo($a) {}
}
?>
See also Object Inheritance, PHP RFC: Covariant Returns and Contravariant Parameters and Classes/IncompatibleSignature
Interfaces Is Not Implemented
[Since 1.9.5] - [ -P Interfaces/IsNotImplemented ] - [ Online docs ]
Classes that implements interfaces, must implements each of the interface's methods. Otherwise, the class shall be marked as abstract .
<?php
class x implements i {
// This method implements the foo method from the i interface
function foo() {}
// The method bar is missing, yet is requested by interface i
function foo() {}
}
interface i {
function foo();
function bar();
}
?>
This problem tends to occur in code that splits interfaces and classes by file. This means that PHP's linting will skip the definitions and not find the problem. At execution time, the definitions will be checked, and a Fatal error will occur.
This situation usually detects code that was forgotten during a refactorisation of the interface or the class and its siblings.
See also and Interfaces
No Literal For Reference
[Since 1.9.5] - [ -P Functions/NoLiteralForReference ] - [ Online docs ]
Method arguments and return values may be by reference. Then, they need to be a valid variable.
Objects are always passed by reference, so there is no need to explicitly declare it.
Expressions, including ternary operator, produce value, and can't be used by reference directly. This is also the case for expression that include one or more reference.
<?php
// variables, properties, static properties, array items are all possible
$a = 1;
foo($a);
//This is not possible, as a literal can't be a reference
foo(1);
function foo(&$int) { return $int; }
// This is not a valid reference
function &bar() { return 2; }
function &bar2() { return 2 + $r; }
?>
Wrongly passing a value as a reference leads to a PHP Notice.
See also and References
Interfaces Don't Ensure Properties
[Since 1.9.5] - [ -P Interfaces/NoGaranteeForPropertyConstant ] - [ Online docs ]
When using an interface as a type, properties are not enforced, nor available.
An interface is a template for a class, which specify the minimum amount of methods and constants. Properties are never defined in an interface, and should not be relied upon.
<?php
interface i {
function m () ;
}
class x implements i {
public $p = 1;
function m() {
return $this->p;
}
}
function foo(i $i, x $x) {
// this is invalid, as $p is not defined in i, so it may be not available
echo $i->p;
// this is valid, as $p is defined in $x
echo $x->p;
}
?>
See also and Interface And Abstract Class
Non Nullable Getters
[Since 1.9.6] - [ -P Classes/NonNullableSetters ] - [ Online docs ]
A getter needs to be nullable when a property is injected.
In particular, if the injection happens with a separate method, there is a time where the object is not consistent, and the property holds a default non-object value.
<?php
class Consistent {
private $db = null;
function __construct(Db $db) {
$this->db = $db;
// Object is immediately consistent
}
// Db might be null
function getDb() {
return $this->db;
}
}
class Inconsistent {
private $db = null;
function __construct() {
// No initialisation
}
// This might be called on time, or not
// This typehint cannot be nullable, nor use null as default
function setDb(DB $db) {
return $this->db;
}
// Db might be null
function getDb() {
return $this->db;
}
}
?>
Too Many Dereferencing
[Since 1.9.7] - [ -P Classes/TooManyDereferencing ] - [ Online docs ]
Linking too many properties and methods, one to the other.
This analysis counts both static calls and normal call; methods, properties and constants. It also takes into account arrays along the way.
The default limit of chaining methods and properties is set to 7 by default.
<?php
// 9 chained calls.
$main->getA()->getB()->getC()->getD()->getE()->getF()->getG()->getH()->getI()->property;
?>
Too many chained methods is harder to read.
Can't Implement Traversable
[Since 1.9.8] - [ -P Interfaces/CantImplementTraversable ] - [ Online docs ]
It is not possible to implement the Traversable interface. The alternative is to implement Iterator or IteratorAggregate , which also implements Traversable .
Traversable may be useful when used with instanceof .
<?php
// This lints, but doesn't run
class x implements Traversable {
}
if( $argument instanceof Traversable ) {
// doSomething
}
?>
See also Traversable, Iterator and IteratorAggregate
Is_A() With String
[Since 1.9.9] - [ -P Php/IsAWithString ] - [ Online docs ]
When using is_a() with a string as first argument, the third argument is compulsory.
<?php
// `is_a() <https://www.php.net/is_a>`_ works with string as first argument, when the third argument is 'true'
if (is_s('A', 'B', true)) {}
// `is_a() <https://www.php.net/is_a>`_ works with object as first argument
if (is_s(new A, 'A')) {}
?>
See also and is_a
Mbstring Unknown Encoding
[Since 1.9.9] - [ -P Structures/MbstringUnknownEncoding ] - [ Online docs ]
The encoding used is not known to the ext/mbstring extension.
This analysis takes in charge all mbstring encoding and aliases. The full list of supported mbstring encoding is available with mb_list_encodings(). Each encoding alias is available with mb_encoding_aliases().
<?php
// Invalid encoding
$str = mb_strtolower($str, 'utf_8');
// Valid encoding
$str = mb_strtolower($str, 'utf8');
$str = mb_strtolower($str, 'UTF8');
$str = mb_strtolower($str, 'UTF-8');
?>
See also and ext/mbstring
Mbstring Third Arg
[Since 1.9.9] - [ -P Structures/MbstringThirdArg ] - [ Online docs ]
Some mbstring functions use the third argument for offset, not for encoding.
Those are the following functions :
- mb_strrichr()
- mb_stripos()
- mb_strrpos()
- mb_strstr()
- mb_stristr()
- mb_strpos()
- mb_strripos()
- mb_strrchr()
- mb_strrichr()
- mb_substr()
<?php
// Display BC
echo mb_substr('ABC', 1 , 2, 'UTF8');
// Yields Warning: `mb_substr() <https://www.php.net/mb_substr>`_ expects parameter 3 to be int, string given
// Display 0 (aka, substring from 0, for length (int) 'UTF8' => 0)
echo mb_substr('ABC', 1 ,'UTF8');
?>
Typo 3 usage
[Since 1.9.9] - [ -P Vendors/Typo3 ] - [ Online docs ]
This analysis reports usage of the Typo 3 CMS.
The current supported version is 11.4
<?php
declare(strict_types=1);
namespace MyVendor\SjrOffers\Controller;
use TYPO3\CMS\Extbase\Mvc\Controller\ActionController;
class OfferController extends ActionController
{
// action methods will be following here
}
?>
See also and Typo3
Concrete5 usage
[Since 1.9.9] - [ -P Vendors/Concrete5 ] - [ Online docs ]
This analysis reports usage of the Concrete 5 framework.
<?php
namespace Application\Controller\PageType;
use Concrete\Core\Page\Controller\PageTypeController;
class BlogEntry extends PageTypeController
{
public function view()
{
}
}
?>
See also and Concrete 5
Immutable Signature
[Since 1.9.9] - [ -P Classes/ImmutableSignature ] - [ Online docs ]
Overwrites makes refactoring a method signature difficult. PHP enforces compatible signature, by checking if arguments have the same type, reference and default values.
In PHP 7.3, typehint had to be the same, or dropped. In PHP 7.4, typehint may be contravariant (arguments), or covariant (returntype).
This analysis may be configured with maxOverwrite . By default, a minimum of 8 overwritten methods is considered difficult to update.
<?php
// Changing any of the four foo() method signature will trigger a PHP warning
class a {
function foo($a) {}
}
class ab1 extends a {
// four foo() methods have to be refactored at the same time!
function foo($ab1) {}
}
class ab2 extends a {
function foo($ab2) {}
}
class ab3 extends ab1 {
function foo($abc1) {}
}
?>
When refactoring a method, all the related methodcall may have to be updated too. Adding a type, a default value, or a new argument with default value won't affect the calls, but only the definitions. Otherwise, calls will also have to be updated.
IDE may help with signature refactoring, such as Refactoring code.
See also Covariance and contravariance (computer science) and extends
Merge If Then
[Since 1.9.9] - [ -P Structures/MergeIfThen ] - [ Online docs ]
Two successive if/then into one, by merging the two conditions.
<?php
// two merge conditions
if ($a == 1 && $b == 2) {
// doSomething()
}
// two distinct conditions
// two nesting
if ($a == 1) {
if ($b == 2) {
// doSomething()
}
}
?>
Wrong Type With Call
[Since 1.9.9] - [ -P Functions/WrongTypeWithCall ] - [ Online docs ]
This analysis checks that a call to a method uses the types.
This analysis is compatible with Union types and with Intersection types.
<?php
function foo(string $a) {
}
// wrong type used
foo(1);
// wrong type used
foo("1");
?>
Currently, this analysis doesn't take into account strict_types = 1 . As such, int and string won't be compatible.
Shell commands
[Since 1.9.9] - [ -P Type/Shellcommands ] - [ Online docs ]
Shell commands, called from PHP.
Shell commands are detected with the italic quotes, and using shell_exec(), system(), exec() and proc_open().
<?php
// Shell command in a `shell_exec() <https://www.php.net/shell_exec>`_ call
shell_exec('ls -1');
// Shell command with backtick operator
`ls -1 $path`;
?>
See also Execution operator, shell_exec and exec
Links Between Parameter And Argument
[Since 2.0.6] - [ -P Dump/ParameterArgumentsLinks ] - [ Online docs ]
Collect various stats about arguments and parameter usage.
A parameter is one slot in the method definition. An argument is a slot in the method call. Both are linked by the method and their respective position in the argument list.
+ Total number of argument usage, linked to a parameter : this excludes arguments from external libraries and native PHP functions. For reference.
+ Number of identical parameter : cases where argument and parameter have the same name.
+ Number of different parameter : cases where argument and parameter have the different name.
+ Number of expression argument : cases where argument is an expression
+ Number of constant argument : cases where the argument is a constant
<?php
function foo($a, $b) {
// some code
}
// $a is the same as the parameter
// $c is different from the paramter $b
foo($a, $c);
const C = 1;
// Foo is called with a constant (1rst argument)
// Foo is called with a expression (2nd argument)
foo(C, 1+3);
?>
Not Equal Is Not !==
[Since 2.0.6] - [ -P Structures/NotEqual ] - [ Online docs ]
Not and Equal operators, used separately, don't amount to the different operator !== .
!$a == $b first turns $a into the opposite boolean, then compares this boolean value to $b . On the other hand, $a !== $b compares the two variables for type and value, and returns a boolean.
<?php
if ($string != 'abc') {
// doSomething()
}
// Here, string will be an boolean, leading
if (!$string == 'abc') {
// doSomething()
}
// operator priority may be confusing
if (!$object instanceof OneClass) {
// doSomething()
}
?>
Note that the instanceof operator may be use with this syntax, due to operator precedence.
See also and Operator Precedence
Php 8.0 Variable Syntax Tweaks
[Since 2.0.8] - [ -P Php/Php80VariableSyntax ] - [ Online docs ]
Several variable syntaxes are added in version 8.0. They extends the PHP 7.0 syntax updates, and fix a number of edges cases.
In particular, new and instanceof now support a way to inline the expression, rather than use a temporary variable.
Magic constants are now accessible with array notation, just like another constant. It is also possible to use method calls : although this is Syntacticly correct for PHP, this won't be executed, as the left operand is a string, and not an object.
<?php
// array name is dynamically build
echo foo$bar[0];
// static method
foo$bar::baz();
// static property
foo$bar::$baz;
// Syntactly correct, but not executable
foo$bar->baz();
// expressions with instanceof and new
$object = new (class_.$name);
$x instanceof (class_$name);
// PHP 7.0 style
$className = class_.$name;
$object = new $className;
?>
See also PHP RFC: Variable Syntax Tweaks and scalar_objects in PHP
Dont Collect Void
[Since 2.0.9] - [ -P Functions/DontUseVoid ] - [ Online docs ]
When a method returns void, there is no need to collect the result. The collected value is always null .
With a void return type, the method is intented to be without return value. This analysis also include methods which are not returning anything, and could be completed with a void returntype.
<?php
function foo() : void {
// doSomething()
}
// This is useless
$result = foo();
// This is useless. It looks like this is a left over from code refactoring
echo foo();
?>
Php 8.0 Only TypeHints
[Since 2.0.9] - [ -P Php/Php80OnlyTypeHints ] - [ Online docs ]
Three scalar typehints are introduced in version 8.0. They are mixed , false and null .
false represents a false boolean, and nothing else. It is more restrictive than a boolean, which accepts true too.
null is an alternative syntax to ? : it allows the type to be null .
mixed is an special typehint which explicitly means any type.
An interface stringable was also introduced to identify objects that may be turned into a string.
Both the above typehints are to be used in conjunction with other types : they can't be used alone.
<?php
// function accepts an A object, or null.
function foo(A|null $x) {}
// same as above
function foo2(A|null $x) {}
// returns an object of class B, or false
function bar($x) : false|B {}
?>
In PHP 7.0, both those values could not be used as a class or interface name, to avoid confusion with the actual booleans, nor null value.
See also and PHP RFC: Union Types 2.0
Union Typehint
[Since 2.0.9] - [ -P Php/Php80UnionTypehint ] - [ Online docs ]
Union typehints allows the specification of several typehint for the same argument or return value.
Several typehints are specified at the same place as a single one. The different values are separated by a pipe character | , like for exceptions
<?php
// Example from the RFC https://wiki.php.net/rfc/union_types_v2
class Number {
private int|float $number;
public function setNumber(int|float $number): void {
$this->number = $number;
}
public function getNumber(): int|float {
return $this->number;
}
}
?>
Nullable is reported as union type. Mixed and iterable are not reported as a union type.
Union types are a PHP 8.0 new feature. They are not compatible with PHP 7.4 and older.
See also PHP RFC: Union Types 2.0, PHP 8 Union types and Type declarations
Wrong Typed Property Default
[Since 2.0.9] - [ -P Classes/WrongTypedPropertyInit ] - [ Online docs ]
Property is typed, yet receives an incompatible value at constructor time.
Initialized type might be a new instance, the return of a method call or an interface compatible object.
<?php
class x {
private A $property;
private B $incompatible;
function __construct() {
// This is compatible
$this->property = new A();
// This is incompatible : new B() expected
$this->incompatible = new C();
}
}
?>
PHP compiles such code, but won't execute it, as it detects the incompatibility at execution time.
See also Functions/WrongReturnedType and Functions/MismatchTypeAndDefault
[Since 2.1.0] - [ -P Classes/HiddenNullable ] - [ Online docs ]
Argument with default value of null are nullable. It works both with the null typehint (PHP 8.0), or the ? operator are not used, setting the default value to null is allowed, and makes the argument nullable.
This works with single types, both classes and scalars; it works with union types but not with intersection types.
This doesn't happen with properties : they must be defined with the nullable type to accept a null value as default value.
This doesn't happen with constant, which can't be typehinted.
<?php
// explicit nullable parameter $s
function bar(?string $s = null) {
// implicit nullable parameter $s
function foo(string $s = null) {
echo $s ?? 'NULL-value';
}
// both display NULL-value
foo();
foo(null);
?>
See also Nullable types, Type declaration and Deprecate implicit nullable parameters #3535
Fn Argument Variable Confusion
[Since 2.1.0] - [ -P Functions/FnArgumentVariableConfusion ] - [ Online docs ]
Avoid using local variables as arrow function arguments.
When a local variable name is used as an argument's name in an arrow function, the local variable from the original scope is not imported. They are now two distinct variables.
When the local variable is not listed as argument, it is then imported in the arrow function.
<?php
function foo() {
$locale = 1;
// Actually ignores the argument, and returns the local variable $locale .
$fn2 = fn ($argument) => $locale;
// Seems similar to above, but returns the incoming argument
$fn2 = fn ($locale) => $locale;
}
?>
See also and Arrow functions
Missing Abstract Method
[Since 2.1.0] - [ -P Classes/MissingAbstractMethod ] - [ Online docs ]
Abstract methods must have a non-abstract version for the class to be complete. A class that is missing one abstract definition cannot be instantiated.
<?php
// This is a valid definition
class b extends a {
function foo() {}
function bar() {}
}
// This compiles, but will emit a fatal error if instantiated
class c extends a {
function bar() {}
}
// This illustration lint but doesn't run.
// moving this class at the beginning of the code will make lint fail
abstract class a {
abstract function foo() ;
}
?>
See also Classes Abstraction.
Undefined Constant Name
[Since 2.1.1] - [ -P Variables/UndefinedConstantName ] - [ Online docs ]
When using the syntax for variable, the name used must be a defined constant. It is not a simple string, like 'x', it is an actual constant name.
Interestingly, it is possible to use a qualified name within , full or partial. PHP will lint such code, and will collect the value of the constant immediately. Since there is no fallback mechanism for fully qualified names, this ends with a Fatal error.
<?php
const x = a;
$a = Hello;
// Display 'Hello' -> $a -> Hello
echo ;
// Yield a PHP Warning
// Use of undefined constant y - assumed 'y' (this will throw an Error in a future version of PHP)
echo ;
// Yield a PHP Fatal error as PHP first checks that the constant exists
//Undefined constant 'y'
echo ;
?>
Using Deprecated Method
[Since 2.1.2] - [ -P Functions/UsingDeprecated ] - [ Online docs ]
A call to a deprecated method has been spotted. A method is deprecated when it bears a @deprecated parameter in its typehint definition.
Deprecated methods which are not called are not reported.
See also and @deprecated
Protocol lists
[Since 2.1.3] - [ -P Type/Protocols ] - [ Online docs ]
List of all protocols that were found in the code.
From the manual : PHP comes with many built-in wrappers for various URL-style protocols for use with the filesystem functions such as fopen(), copy(), file_exists() and filesize().
<?php
// Example from the PHP manual, with the glob:// wrapper
// Loop over all *.php files in ext/spl/examples/ directory
// and print the filename and its size
$it = new DirectoryIterator(glob://ext/spl/examples/*.php);
foreach($it as $f) {
printf(%s: %.1FK\n, $f->getFilename(), $f->getSize()/1024);
}
?>
See also and Supported Protocols and Wrappers
Cyclic References
[Since 2.1.3] - [ -P Classes/CyclicReferences ] - [ Online docs ]
Avoid cyclic references.
Cyclic references happen when an object points to another object, which reciprocate. This is particularly possible with classes, when the child class has to keep a reference to the parent class.
<?php
class a {
private $p = null;
function foo() {
$this->p = new b();
// the current class is stored in the child class
$this->p->m($this);
}
}
class b {
private $pb = null;
function n($a) {
// the current class keeps a link to its parent
$this->pb = $a;
}
}
?>
Cyclic references, or circular references, are memory intensive : only the garbage collector can understand when they may be flushed from memory, which is a costly operation. On the other hand, in an acyclic reference code, the reference counter will know immediately know that an object is free or not.
See also About circular references in PHP and A Journey to find a memory leak
Double Object Assignation
[Since 2.1.2] - [ -P Structures/DoubleObjectAssignation ] - [ Online docs ]
Make sure that assigning the same object to two variables is the intended purpose.
<?php
// $x and $y are the same object, as they both hold a reference to the same object.
// This means that changing $x, also changes $y.
$x = $y = new Z();
// $a and $b are distinct values, by default
$a = $b = 1;
?>
See also and class
Wrong Argument Type
[Since 2.1.3] - [ -P Functions/WrongArgumentType ] - [ Online docs ]
Checks that the type of the argument is consistent with the type of the called method.
<?php
function foo(int $a) { }
//valid call, with an integer
foo(1);
//invalid call, with a string
foo('asd');
?>
This analysis is valid with PHP 8.0.
Mismatch Properties Typehints
[Since 2.1.4] - [ -P Classes/MismatchProperties ] - [ Online docs ]
Properties must match within the same family.
When a property is declared both in a parent class, and a child class, they must have the same type. The same type includes a possible null value.
This doesn't apply to private properties, which are only visible locally.
<?php
// property $p is declared as an object of type a
class x {
protected A $p;
}
// property $p is declared again, this time without a type
class a extends x {
protected $p;
}
?>
This code will lint, but not execute.
No Need For Triple Equal
[Since 2.1.4] - [ -P Structures/NoNeedForTriple ] - [ Online docs ]
There is no need for the identity comparison when the methods returns the proper type.
<?php
// foo() returns a string.
if ('a' === foo()) {
// doSomething()
}
function foo() : string {
return 'a';
}
?>
Array_merge Needs Array Of Arrays
[Since 2.1.4] - [ -P Structures/ArrayMergeArrayArray ] - [ Online docs ]
When collecting data to feed array_merge(), use an array of array as default value. array(array()) is the neutral value for array_merge();
This analysis also reports when the used types are not an array : array_merge() does not accept scalar values, but only arrays.
<?php
// safe default value
$a = array(array());
// when $list is empty, it is
foreach($list as $l) {
$a[] = $l;
}
$b = array_merge($a);
?>
Since PHP 7.4, it is possible to call array_merge() without an argument : this means the default value may an empty array. This array shall not contain scalar values.
See also and array_merge
Wrong Type For Native PHP Function
[Since 2.1.5] - [ -P Php/WrongTypeForNativeFunction ] - [ Online docs ]
This analysis reports calls to a PHP native function with a wrongly typed value.
<?php
// valid calls
echo exp(1);
echo exp(2.5);
// invalid calls
echo exp(1);
echo exp(array(2.5));
// valid call, but invalid math
// -1 is not a valid value for `log() <https://www.php.net/log>`_, but -1 is a valid type (int) : it is not reported by this analysis.
echo log(-1);
?>
See also and PHP 7.1 no longer converts string to arrays the first time a value is assigned with square bracket notation
Catch With Undefined Variable
[Since 2.1.5] - [ -P Exceptions/CatchUndefinedVariable ] - [ Online docs ]
Always initialize every variable before the try block, when they are used in a catch block. If the exception is raised before the variable is defined, the catch block may have to handle an undefined variable, leading to more chaos.
<?php
$a = 1;
try {
mayThrowAnException();
$b = 2;
} catch (\Exception $e) {
// $a is already defined, as it was done before the try block
// $b may not be defined, as it was initialized after the exception-throwing expression
echo $a + $b;
}
?>
See also catch and Non-capturing exception catches in PHP 8
Swapped Arguments
[Since 2.1.5] - [ -P Classes/SwappedArguments ] - [ Online docs ]
Overwritten methods must be compatible, but argument names is not part of that compatibility.
Methods with the same name, in two classes of the same hierarchy, must be compatible for typehint, default value, reference. The name of the argument is not taken into account when checking such compatibility, at least until PHP 7.4.
<?php
class x {
function foo($a, $b) {}
function bar($a, $b) {}
}
class y extends x {
// foo is compatible (identical) with the above class
function foo($a, $b) {}
// bar is compatible with the above class, yet, the argument might not receive what they expect.
function bar($b, $a) {}
}
?>
This analysis reports argument lists that differs in ordering. This analysis doesn't report argument lists that also differs in argument names.
Different Argument Counts
[Since 2.1.6] - [ -P Classes/DifferentArgumentCounts ] - [ Online docs ]
Two methods with the same name shall have the same number of compulsory argument. PHP accepts different number of arguments between two methods, if the extra arguments have default values. Basically, they shall be called interchangeably with the same number of arguments.
The number of compulsory arguments is often mistaken for the same number of arguments. When this is the case, it leads to confusion between the two signatures. It will also create more difficulties when refactoring the signature.
While this code is legit, it is recommended to check if the two signatures could be synchronized, and reduce future surprises.
<?php
class x {
function foo($a ) {}
}
class y extends x {
// This method is compatible with the above, its signature is different
function foo($a, $b = 1) {}
}
?>
Use PHP Attributes
[Since 2.1.6] - [ -P Php/UseAttributes ] - [ Online docs ]
PHP 8.0 attributes in use.
<?php
#[foo(4)]
class x {
}
?>
See also PHP RFC: Shorter Attribute Syntax, Attributes Amendements and Shorter Attribute Syntax Change
Use NullSafe Operator
[Since 2.1.6] - [ -P Php/UseNullSafeOperator ] - [ Online docs ]
The nullsafe operator ?-> is an alternative to the object operator -> . It silently fails the whole expression if a null is used for object.
<?php
$o = null;
// PHP 8.0 Failsafe : $r = null;
$r = $o->method();
// PHP 7.4- : Call to a member function method() on null
$r = $o->method();
?>
See also and PHP RFC: Nullsafe operator
Use Closure Trailing Comma
[Since 2.1.6] - [ -P Php/UseTrailingUseComma ] - [ Online docs ]
Use a trailing comma in the closure's use list. This feature was added in PHP 8.0.
<?php
// PHP 8.0 valid syntax
$f = function foo() use ($a, ) { };
// always valid syntax for closure
$f = function foo() use ($a ) { };
?>
See also and Trailing Comma In Closure Use List
Unknown Parameter Name
[Since 2.1.6] - [ -P Functions/UnknownParameterName ] - [ Online docs ]
The name of the parameter doesn't belong to the method signature. Named arguments were introduced in PHP 8.0.
Named arguments errors will also arise when spreading a hash array with arbitrary number of arguments. For example, with array_merge(), the array should not use named keys.
<?php
// All good
foo(a:1, b:2, c:3);
foo(...['a':1, 'b':2, 'c':3]);
// A is not a parameter name, it should be a : names are case sensitive
foo(A:1, b:2, c:3);
foo(...['A':1, 'b':2, 'c':3]);
function foo($a, $b, $c) {}
array_merge(['a' => [1], 'b' => [2]]);
?>
See also Named Arguments and Functions/WrongArgumentNameWithPhpFunction
Missing Some Returntype
[Since 2.1.7] - [ -P Typehints/MissingReturntype ] - [ Online docs ]
The specified typehints are not compatible with the returned values.
The code of the method may return other types, which are not specified and will lead to a PHP fatal error. It is the case for insufficient typehints, when a typehint is missing, or inconsistent typehints, when the method returns varied types.
<?php
// correct return typehint
function fooSN() : ?string {
return shell_exec('ls -hla');
}
// insufficient return typehint
// `shell_exec() <https://www.php.net/shell_exec>`_ may return null or string. Here, only string in specified for fooS, and that may lead to a Fatal error
function fooS() : string {
return shell_exec('ls -hla');
}
// inconsistent return typehint
function bar() : int {
return rand(0, 10) ? 1 : b;
}
?>
The analysis reports a method when it finds other return types than the one expected. In the case of multiple typehints, as for the last example, the PHP code may require an upgrade to PHP 8.0.
Don't Pollute Global Space
[Since 2.1.7] - [ -P Php/DontPolluteGlobalSpace ] - [ Online docs ]
Avoid creating definitions in the global name space.
The global namespace is the default namespace, where all functions, classes, constants, traits and interfaces live. The global namespace is also known as the root namespace.
In particular, PHP native classes usually live in that namespace. By creating functions in that namespace, the code may encounter naming conflict, when the PHP group decides to use a name that the code also uses. This already happened in PHP version 5.1.1, where a Date native class was introduced, and had to be disabled in the following minor version.
Nowadays, conflicts appear between components, which claim the same name.
See also and Using namespaces: fallback to global function/constant
Cast Unset Usage
[Since 2.1.8] - [ -P Php/CastUnsetUsage ] - [ Online docs ]
Usage of the `(unset)` cast operator. It is removed in PHP 8.0, and was deprecated since PHP 7.2.0.
<?php
$a = 1;
(unset) $a;
// functioncall is OK
unset($a);
?>
See also and Unset casting
$php_errormsg Usage
[Since 2.1.8] - [ -P Php/PhpErrorMsgUsage ] - [ Online docs ]
$php_errormsg is removed since PHP 8.0. $php_errormsg tracks the last error message, with the directive track_errors`. All was removed in PHP 8.0, and shall be replaced with `error_get_last().
<?php
function foo() {
global $php_errormsg;
echo 'Last error: '.$php_errormsg;
echo 'Also, last error: '.`error_get_last() <https://www.php.net/error_get_last>`_;
}
?>
Mismatch Parameter Name
[Since 2.1.8] - [ -P Functions/MismatchParameterName ] - [ Online docs ]
Parameter name change in overwritten method. This may lead to errors when using PHP 8.0 named arguments.
PHP use the name of the parameter in the method whose code is executed. When the name change between the method and the overwritten method, the consistency is broken.
<?php
class x {
function getValue($name) {}
}
class y extends x {
// consistent with the method above
function getValue($name) {}
}
class z extends x {
// inconsistent with the method above
function getValue($label) {}
}
?>
Here is another example, in early PHP 8.0 (courtesy of Carnage).
<?php
interface Pager
{
public function fetch($page = 0, ...$categories);
}
class DbPager implements Pager
{
public function fetch($seite = 0, ...$kategorien)
{
var_dump($kategorien);
}
}
$dbPager = new DbPager();
$dbPager->fetch(page: 1, categories: 2);
?>
Multiple Declaration Of Strict_types
[Since 2.1.8] - [ -P Php/MultipleDeclareStrict ] - [ Online docs ]
At least two declare() commands are declaring `strict_types` in one file. Only one is sufficient, and should be the first expression in the file.
Indeed, any `strict_types` set to 1 will have the final word. Setting `strict_types` to 0 will not revert the configuration, wherever is this call made.
<?php
declare(strict_types=1);
declare(strict_types=1);
// rest of the code
?>
See also and Declare
Array_Fill() With Objects
[Since 2.1.9] - [ -P Structures/ArrayFillWithObjects ] - [ Online docs ]
array_fill() fills an array with identical objects, not copies nor clones. This means that all the filled objects are a reference to the same object. Changing one of them will change any of them.
Make sure this is the intended effect in the code.
<?php
$x = new StdClass();
$array = array_fill(0, 10, $x);
$array[3]->y = Set in object #3;
// displays Set in object #3;
echo $array[5]->y;
?>
This applies to array_pad() too. It doesn't apply to array_fill_keys(), as objects will be cast to a string before usage in this case.
Modified Typed Parameter
[Since 2.1.9] - [ -P Functions/ModifyTypedParameter ] - [ Online docs ]
Reports modified parameters, which have a non-scalar typehint. Such variables should not be changed within the body of the method. Unlike typed properties, which always hold the expected type, typed parameters are only guaranteed type at the beginning of the method block.
<?php
class x {
function foo(Y $y) {
// $y is type Y
// A cast version of $y is stored into $yAsString. $y is untouched.
$yAsString = (string) $y;
// $y is of type 'int', now.
$y = 1;
// Some more code
// display the string version.
echo $yAsString;
// so, Y $y is now raising an error
echo $y->name;
}
}
?>
This problem doesn't apply to scalar types : by default, PHP pass scalar parameters by value, not by reference. Class types are always passed by reference.
This problem is similar to Classes/DontUnsetProperties : the static specification of the property may be unset, leading to confusing 'undefined property', while the class hold the property definition.
Assumptions
[Since 2.1.9] - [ -P Php/Assumptions ] - [ Online docs ]
Assumptions in the code, that leads to possible bugs.
Some conditions may be very weak, and lead to errors. For example, the code below checks that the variable `$a` is not null, then uses it as an array. There is no relationship between 'not null' and 'being an array', so this is an assumption.
<?php
// Assumption : if $a is not null, then it is an array. This is not always the case.
function foo($a) {
if ($a !== null) {
echo $a['name'];
}
}
// Assumption : if $a is not null, then it is an array. Here, the typehint will ensure that it is the case.
// Although, a more readable test is `is_array() <https://www.php.net/is_array>`_
function foo(?array $a) {
if ($a !== null) {
echo $a['name'];
}
}
?>
See also and From assumptions to assertions
PHP 8.0 Removed Directives
[Since 2.1.9] - [ -P Php/Php80RemovedDirective ] - [ Online docs ]
List of directives that are removed in PHP 8.0.
In PHP 8.0, `track_errors` was removed.
You can detect valid directives with ini_get(). This native function will return false, when the directive doesn't exist, while actual directive values will be returned as a string.
See `Deprecation track_errors
Unsupported Types With Operators
[Since 2.1.9] - [ -P Structures/UnsupportedTypesWithOperators ] - [ Online docs ]
Arrays, resources and objects are generally not accepted with unary and binary operators.
The operators are `+`, `-`, `*`, `/`, `**`, `%`, `<<`, `>>`, `&`, `|`, `^`, `~`, `++` and `--`.
<?php
var_dump([] % [42]);
// int(0) in PHP 7.x
// TypeError in PHP 8.0 +
// Also impossible usage : index are string or int
$a = [];
$b = $c[$a];
?>
In PHP 8.0, the rules have been made stricter and more consistent.
The only valid operator is `+`, combined with arrays in both operands. Other situations throw TypeError .
See also Stricter type checks for arithmetic/bitwise operators and TypeError
Negative Start Index In Array
[Since 2.1.9] - [ -P Arrays/NegativeStart ] - [ Online docs ]
Negative starting index in arrays changed in PHP 8.0. Until then, they were ignored, and automatic index started always at 0. Since PHP 8.0, the next index is calculated.
The behavior will break code that relies on automatic index in arrays, when a negative index is used for a starter.
<?php
$x = [-5 => 2];
$x[] = 3;
print_r($x);
/*
PHP 7.4 and older
Array
(
[-5] => 2
[0] => 3
)
*/
/*
PHP 8.0 and more recent
Array
(
[-5] => 2
[-4] => 3
)
*/
?>
See also and PHP RFC: Arrays starting with a negative index
Nullable With Constant
[Since 2.1.9] - [ -P Functions/NullableWithConstant ] - [ Online docs ]
Arguments are automatically nullable with a literal null. They used to also be nullable with a constant null, before PHP 8.0.
<?php
// Extracted from https://github.com/php/php-src/blob/master/UPGRADING
// Replace
function test(int $arg = CONST_RESOLVING_TO_NULL) {}
// With
function test(?int $arg = CONST_RESOLVING_TO_NULL) {}
// Or
function test(int $arg = null) {}
?>
PHP 8.0 Resources Turned Into Objects
[Since 2.2.0] - [ -P Php/Php80RemovesResources ] - [ Online docs ]
Multiple PHP native functions now return objects, not resources. Any check on those values with is_resource() is now going to fail.
The affected functions are the following :
+ curl_init()
+ curl_multi_init()
+ curl_share_init()
+ deflate_init()
+ enchant_broker_init()
+ enchant_broker_request_dict()
+ enchant_broker_request_pwl_dict()
+ inflate_init()
+ msg_get_queue()
+ openssl_csr_new()
+ openssl_csr_sign()
+ openssl_pkey_new()
+ openssl_x509_read()
+ sem_get()
+ shm_attach()
+ shmop_open()
+ socket_accept()
+ socket_addrinfo_bind()
+ socket_addrinfo_connect()
+ socket_create_listen()
+ socket_create()
+ socket_import_stream()
+ socket_wsaprotocol_info_import()
+ xml_parser_create_ns()
+ xml_parser_create()
See also and Resource to object migration
PHP 80 Named Parameter Variadic
[Since 2.2.0] - [ -P Php/Php80NamedParameterVariadic ] - [ Online docs ]
Named parameter with variadic have been renamed from 0 to 'parameter name' in PHP 8.0.
<?php
function foo($a, ...$b) {
print_r($b);
}
foo(3, 4);
foo(3, b: 4); // PHP 8 only
foo(...[2, b=> [3, 4]]); // PHP 8 only
?>
In PHP 7.0, with positional argument only, the content of $b is in an array, index 0. This is also true with PHP 8.0.
In PHP 8.0, with named arguments, the content of $b is in an array, index 'b';
Since the behavior of the variadic depends on the calling syntax (with or without named parameter), the receiving must ensure the correct reception, and handle both cases.
Wrong Attribute Configuration
[Since 2.2.0] - [ -P Php/WrongAttributeConfiguration ] - [ Online docs ]
A class is attributed to the wrong PHP structure.
<?php
#[Attribute(Attribute::TARGET_CLASS)]
class ClassAttribute { }
// Wrong
#[ClassAttribute]
function foo () {}
// OK
#[ClassAttribute]
class y {}
?>
See also and Declaring Attribute Classes
Cancelled Parameter
[Since 2.2.0] - [ -P Functions/CancelledParameter ] - [ Online docs ]
A parameter is cancelled, when its value is hardcoded, and cannot be changed by the calling expression. The argument is in the signature, but it is later hardcoded to a literal value : thus, it is not usable, from the caller point of view.
Reference argument are omitted in this rule, as their value changes, however hardcoded, may have an impact on the calling code.
<?php
function foo($a, $b) {
// $b is cancelled, and cannot be changed.
$b = 3;
// $a is the only parameter here
return $a + $b;
}
function bar($a, $b) {
// $b is actually processed
$c = $b;
$c = process($c);
$b = $c;
// $a is the only parameter here
return $a + $b;
}
?>
Constant Typo Looks Like A Variable
[Since 2.2.0] - [ -P Variables/ConstantTypo ] - [ Online docs ]
A constant bears the same name as a variable. This might be a typo.
When the constant doesn't exist, PHP 8.0 yields a Fatal Error and stops execution. PHP 7.4 turns the undefined constant into its string equivalent.
<?php
// Get an object or null
$object = foo();
// PHP 8.0 stops here, with a Fatal Error
// PHP 7.4 makes this a string, and the condition is always true
if (!empty(object)) {
// In PHP 7.4, this is not protected by the condition, and may yield an error.
$object->doSomething();
}
?>
This analysis is case sensitive.
Final Private Methods
[Since 2.2.0] - [ -P Classes/FinalPrivate ] - [ Online docs ]
PHP's private methods cannot be overwritten, as they are dedicated to the current class. That way, the final keyword is useless.
PHP 8.0 warns when it finds such a method.
<?php
class foo {
// Final and private both prevent child classes to overwrite the method
final private function bar() {}
// Final and protected (or public) keep this method available, but not overwritable
final protected function bar() {}
}
?>
See also and Final Keyword
Array_Map() Passes By Value
[Since 2.2.0] - [ -P Structures/ArrayMapPassesByValue ] - [ Online docs ]
array_map() requires the callback to receive elements by value. Unlike array_walk(), which accepts by value or by reference, depending on the action taken.
PHP 8.0 and more recent emits a Warning
<?php
// Example, courtery of Juliette Reinders Folmer
function trimNewlines(&$line, $key) {
$line = str_replace(array(\n, \r), '', $line);
}
$original = [
text\n\n,
text\n\r
];
$array = $original;
array_walk($array, 'trimNewlines');
var_dump($array);
array_map('trimNewlines', $original, [0, 1]);
?>
See also and array_map
Missing __isset() Method
[Since 2.2.0] - [ -P Php/MissingMagicIsset ] - [ Online docs ]
When using empty() on magic properties, the magic method __isset() must be implemented.
<?php
class foo {
function __get($name) { return 'foo'; }
// No __isset method
}
// Return TRUE, until __isset() exists
var_dump(
empty((new foo)->bar);
);
?>
See also and When empty is not empty
Modify Immutable
[Since 2.2.0] - [ -P Attributes/ModifyImmutable ] - [ Online docs ]
A class, marked as immutable, is being modified.
This attribute is supported as a PHPdoc comment, `@immutable, and as a PHP 8.0 attribute.
<?php
/** @Immutable */
#[Immutable]
class x {
public $x = 1, $y, $z;
}
$x = new X;
// $x->x is modified, while it should not
$x->x = 2 + $x->z;
// $x->z is read only, as expected
?>
See also phpstorm-stubs/meta/attributes/Immutable.php and PhpStorm 2020.3 EAP \#4: Custom PHP 8 Attributes
Reserved Match Keyword
[Since 2.2.1] - [ -P Php/ReservedMatchKeyword ] - [ Online docs ]
Match is a new instruction in PHP 8.0. For that, it becomes a reserved keyword, and cannot be used in various situations.
<?php
// Match as a standalone keyword
use X as Match;
// No more use as a typehint
function foo(match $a ) : match {}
$a instanceof match;
// No use as method name or function name
matCH(a, 4) ;
$method->MAtch();
$static::MATch();
// Match in a Fully qualified name is OK
b\match ;
// Match a property name or a class constant is OK
$match->maTCH;
C::MATCH;
?>
See also and Match expression V2
Avoid get_object_vars()
[Since 2.2.1] - [ -P Php/AvoidGetobjectVars ] - [ Online docs ]
get_object_vars() changes behavior between PHP 7.3 and 7.4. It also behaves different within and outside a class.
<?php
// Illustration courtesy of Doug Bierer
$obj = new ArrayObject(['A' => 1,'B' => 2,'C' => 3]);
var_dump($obj->getArrayCopy());
var_dump(get_object_vars($obj));
?>
See also get_object_vars script on 3V4L and The Strange Case of ArrayObject
Only Container For Reference
[Since 2.2.0] - [ -P Php/OnlyVariableForReference ] - [ Online docs ]
When a PHP function requires an argument to be a reference, it cannot be called with a literal value.
The call must be made with a variable, or any assimilated data container : array, property or static property.
<?php
// This is not possible
preg_match('/a/', $string, []);
// This is working
preg_match('/a/', $string, $r);
?>
See also and Passing arguments by reference
Cannot Use Static For Closure
[Since 2.2.2] - [ -P Functions/CannotUseStaticForClosure ] - [ Online docs ]
The reported closures and arrow functions cannot use the static keyword.
Closures that makes use of the $this pseudo-variable cannot use the static keyword, at it prevents the import of the $this context in the closure. It will fail at execution.
Closures that makes use of the bindTo() method, to change the context of execution, also cannot use the static keyword. Even if $this is not used in the closure, the static keyword prevents the call to bindTo().
<?php
class x {
function foo() {
// Not possible, $this is now undefined in the body of the closure
static function () { return $this->a;};
}
function foo2() {
// Not possible, $this is now undefined in the body of the arrow function
static fn () => $this->a;
}
function foo3() {
// Not possible, the closure gets a new context before being called.
$a = static fn () => $ba;
$this->foo4($a);
}
function foo4($c) {
$c->bindTo($this);
$c();
}
}
?>
See also and Static anonymous functions
Only First Byte
[Since 2.2.2] - [ -P Structures/OnlyFirstByte ] - [ Online docs ]
When assigning a char to a string with an array notation, only the first byte is used.
<?php
$str = 'xy';
// first letter is now a
$str[0] = 'a';
// second letter is now b, c is ignored
$str[1] = 'bc';
?>
See also and String access and modification by character
Restrict Global Usage
[Since 2.2.2] - [ -P Php/RestrictGlobalUsage ] - [ Online docs ]
$GLOBALS access, as whole, is forbidden. In PHP 8.1, it is not possible to this as a variable, but only access its individual values.
<?php
// Example extracted from the RFC (see link below)
// Continues to work:
foreach ($GLOBALS as $var => $value) {
echo $var . ' => ' . $value . PHP_EOL;
}
// Generates compile-time error:
$GLOBALS = [];
$GLOBALS += [];
$GLOBALS =& $x;
$x =& $GLOBALS;
unset($GLOBALS);
?>
See also and Restrict $GLOBALS usage
Inherited Property Type Must Match
[Since 2.2.2] - [ -P Classes/InheritedPropertyMustMatch ] - [ Online docs ]
Properties that are inherited between classes must match.
This affect public and protected properties. Private properties are immune to this rule, as they actually are distinct properties.
<?php
class A {
private A $a;
protected array $b;
public $c;
}
class B extends A {
private A $a; // OK, as it is private
protected int $b; // type must match with the previous definition
public $c; // no type behaves just like a type : it must match too.
}
?>
See also and Properties
No Object As Index
[Since 2.2.2] - [ -P Structures/NoObjectAsIndex ] - [ Online docs ]
PHP accepts objects as index, though it will report various error messages when this happens.
<?php
$s = 'Hello';
$o = new stdClass();
try {
$s[$o] = 'A';
} catch (\Throwable $e) {
echo $e->getMessage(), \n;
//Cannot access offset of type stdClass on string
}
?>
Thanks to George Peter Banyard for the inspiration.
See also and Use an object as an offet
Class Overreach
[Since 2.2.2] - [ -P Classes/ClassOverreach ] - [ Online docs ]
An object of class A may reach any private or protected properties, constants or methods in another object of the same class. This is a PHP feature, though seldom known.
This feature is also called class invasion.
<?php
class A {
private $p = 1;
public function foo(A $a) {
return $a->p + 1;
}
}
echo (new A)->foo(new A);
?>
See also Visibility from other objects and spatie/invade
Inherited Static Variable
[Since 2.2.2] - [ -P Variables/InheritedStaticVariable ] - [ Online docs ]
Static variables are distinct when used in an inherited static method. In PHP 8.1, the static variable will also be inherited, and shared between the two methods, like a static property.
<?php
// Code extracted from the RFC
class A {
public static function counter() {
static $i = 0;
return ++$i;
}
}
class B extends A {}
var_dump(A::counter()); // int(1)
var_dump(A::counter()); // int(2)
var_dump(B::counter()); // int(1)
var_dump(B::counter()); // int(2)
?>
See also and PHP RFC: Static variables in inherited methods
Enum Usage
[Since 2.2.2] - [ -P Php/EnumUsage ] - [ Online docs ]
PHP's enumeration. Introduced in PHP 8.1.
<?php
enum X {
case A;
case B;
}
?>
See also and Enumerations in PHP
PHP 8.1 Removed Directives
[Since 2.2.3] - [ -P Php/Php81RemovedDirective ] - [ Online docs ]
List of directives that are removed in PHP 8.1.
In PHP 8.1, the following directives were removed :
- `mysqlnd.fetch_data_copy`
- `filter.default`
- `filter.default_options`
- `auto_detect_line_endings`
- `oci8.old_oci_close_semantics`
You can detect valid directives with ini_get(). This native function will return false, when the directive doesn't exist, while actual directive values will be returned as a string.
See also and PHP RFC: Deprecations for PHP 8.1
Htmlentities Using Default Flag
[Since 2.2.3] - [ -P Structures/HtmlentitiescallDefaultFlag ] - [ Online docs ]
htmlspecialchars(), htmlentities(), htmlspecialchars_decode(), html_entity_decode() and get_html_translation_table(), are used to prevent injecting special characters in HTML code. As a bare minimum, they take a string and encode it for HTML.
The second argument of the functions is the type of protection. The protection may apply to quotes or not, to HTML 4 or 5, etc. It is highly recommended to set it explicitly.
In PHP 8.1, the default value of this parameter has changed. It used to be ENT_COMPAT and is now ENT_QUOTES | ENT_SUBSTITUTE . The main difference between the different configuration is that the single quote, which was left intact so far, is now protected HTML style.
<?php
$str = 'A quote in <b>bold</b> : \' and ';
// PHP 8.0 outputs, without depending on the php.ini: A quote in <b>bold</b> : ' and "
echo htmlentities($str);
// PHP 8.1 outputs, while depending on the php.ini: A quote in <b>bold</b> : ' and "
echo htmlentities($str);
?>
See also htmlentities, htmlspecialchars and
Openssl Encrypt Default Algorithm Change
[Since 2.2.3] - [ -P Php/OpensslEncryptAlgoChange ] - [ Online docs ]
openssl_pkcs7_encrypt() and openssl_cms_encrypt() will now default to using AES-128-CBC rather than RC2-40. The RC2-40 cipher is considered insecure and not enabled by default in OpenSSL 3.
This means that the default argument of OPENSSL_CIPHER_RC2_40 is replaced by OPENSSL_CIPHER_AES_128_CBC.
<?php
// extracted from the PHP documentation
// encrypt it
if (openssl_pkcs7_encrypt(msg.txt, enc.txt, $key,
array(To => nighthawk@example.com, // keyed syntax
From: HQ <hq@example.com>, // indexed syntax
Subject => Eyes only))) {
// message encrypted - send it!
exec(ini_get(sendmail_path) . < enc.txt);
}
?>
PHP 8.1 Removed Constants
[Since 1.6.8] - [ -P Php/Php81RemovedConstant ] - [ Online docs ]
The following PHP native constants were disabled in PHP 8.1. They are not removed, but they have no more effect.
- MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH
- MYSQLI_STORE_RESULT_COPY_DATA
- FILE_BINARY
- FILE_TEXT
- FILTER_SANITIZE_STRING
See also and PHP RFC: Deprecations for PHP 8.1
Wrong Argument Name With PHP Function
[Since 2.2.3] - [ -P Functions/WrongArgumentNameWithPhpFunction ] - [ Online docs ]
The name of the argument provided is not a valid parameter name for that PHP native function or method.
<?php
// those are the valid names
strcmp(string1: 'a', string2: 'b');
// those are not the valid names
strcmp(string: 'a', stringToo: 'b');
?>
This analysis may be configured with extra PHP extensions or external packages.
See also and Functions/UnknownParameterName
Duplicate Named Parameter
[Since 2.2.3] - [ -P Functions/DuplicateNamedParameter ] - [ Online docs ]
Two parameters have the same name in a method call. This will yield a Fatal error at execution time.
<?php
function foo($a, $b) {}
// parameters are all distinct
foo(a:1, b:2);
// parameter a is double
foo(a:1, a:1);
?>
See also and Function arguments
PHP Native Class Type Compatibility
[Since 2.2.4] - [ -P Php/NativeClassTypeCompatibility ] - [ Online docs ]
PHP enforces the method compatibility with native classes and interfaces.
This means that classes that extends native PHP classes or interfaces must declare compatible types. They can't omit typing, like it was the case until PHP 8.0.
<?php
class a extends RecursiveFilterIterator {
// fully declared method
function hasChildren(): bool {
return true;
}
// `key() <https://www.php.net/key>`_ returns mixed. Omitting the type used to be quiet
function `key() <https://www.php.net/key>`_ {}
// #[\ReturnTypeWillChange] is taken into account
}
?>
This is needed for compatibility with PHP 8.0. This is probably good for older versions too, although it is not reported.
The attribute ReturnTypeWillChange is taken into account by this rule. Note that it is not detected when auditing with PHP < 8.0, so it won't have effect until this version. The attribute was declared in PHP 8.1, though it is also taken into account when auditing with PHP 8.0.
See also and method-compatibility
Missing Attribute Attribute
[Since 2.2.4] - [ -P Attributes/MissingAttributeAttribute ] - [ Online docs ]
While not strictly required it is recommended to create an actual class for every attribute.
<?php
namespace Example;
use Attribute;
#[Attribute]
class MyAttribute
{
}
#Missing the above attribute
class MyOtherAttribute
{
}
?>
See also and Declaring Attribute Classes
No Null For Native PHP Functions
[Since 2.2.5] - [ -P Php/NoNullForNative ] - [ Online docs ]
Null is not acceptable anymore as an argument, for PHP native functions that require a non-nullable argument.
Until PHP 8.1, it was magically turned into an empty string.
<?php
$haystack = 'abc';
// $needle was omitted...
echo strpos($haystack, $needle);
?>
See also and PHP RFC: Deprecate passing null to non-nullable arguments of internal functions
Calling Static Trait Method
[Since 2.2.5] - [ -P Php/CallingStaticTraitMethod ] - [ Online docs ]
Calling directly a static method, defined in a trait is deprecated. It emits a deprecation notice in PHP 8.1.
<?php
trait T {
public static function t() {
//
}
}
T::t();
?>
Calling the same method, from the class point of view is valid.
See also and PHP RFC: Deprecations for PHP 8.1
No Referenced Void
[Since 2.2.4] - [ -P Functions/NoReferencedVoid ] - [ Online docs ]
There is no point returning a reference with a void type. This is now reported as deprecated in PHP 8.1.
<?php
function &test(): void {}
?>
See also and PHP RFC: Deprecations for PHP 8.1
PHP Native Interfaces and Return Type
[Since 2.3.0] - [ -P Php/JsonSerializeReturnType ] - [ Online docs ]
Native PHP interface which define a type, expect the derived methods to use the same time. In particular, a mixed return type was added to the jsonSerialize() of the JsonSerialize PHP interface.
In PHP 8.1, the mixed return type is now enforced, and a deprecated notice is displayed.
One solution is to add the good return type, or to use the `#[ReturnTypeWillChange]` attribute.
<?php
class MyJsonSerialize implements jsonserialize {
function json`serialize() <https://www.php.net/serialize>`_ : int {}
}
?>
This rule covers the following interfaces :
+ ArrayAccess
+ Countable
+ Exception
+ FilterIterator
+ Iterator
+ JsonSerializable
+ php_user_filter
+ SessionHandlerInterface
See also and JsonSerializable::jsonSerialize
Final Constant
[Since 2.3.0] - [ -P Php/FinalConstant ] - [ Online docs ]
Final modifier for class constants.
<?php
class MyClass {
final const X = 1; // This constant cannot be redefined
const Y = 2; // This constant might be redefined in a child
private const Z = 3; // This private, and can't be made final, because it is not available anyway
}
?>
See also https://www.php.net/manual/en/language.oop5.final.php and https://php.watch/versions/8.1/final-class-const
Never Typehint Usage
[Since 2.3.0] - [ -P Php/NeverTypehintUsage ] - [ Online docs ]
Never is a typehint, which characterize methods that never return a value. It will either terminate the execution or throw an exception.
<?php
function redirect(string $url): never {
header('Location: ' . $url);
exit();
}
?>
See also and The “never” Return Type for PHP
PHP 8.1 Typehints
[Since 2.3.0] - [ -P Php/PHP81scalartypehints ] - [ Online docs ]
A new scalar typehint was introduced : never.
It can't be used before PHP 8.1, and will be confused with classes or interfaces.
<?php
function test() : never
{
exit();
}
?>
See also and PHP RFC: noreturn type
Named Parameter Usage
[Since 2.3.0] - [ -P Php/NamedParameterUsage ] - [ Online docs ]
Named parameters is a way to call a method, by specifying the name of the argument, instead of their position order.
Named parameters works for both custom methods and PHP native functions.
<?php
// named parameters
foo(a : 1, b : 2);
foo(b : 2, a : 1);
// positional parameters
foo(1, 2);
function foo($a, $b) { }
?>
First Class Callable
[Since 2.3.0] - [ -P Php/FirstClassCallable ] - [ Online docs ]
A syntax using ellipsis was introduced to make it easy to make a method into a callable.
<?php
// Using ellipsis as the only argument
$a = $object->method(...);
// Old style equivalent
$a = array($object, 'method');
// calling the closure.
$a();
?>
See also and PHP RFC: First-class callable syntax
New Functions In PHP 8.1
[Since 2.3.0] - [ -P Php/Php81NewFunctions ] - [ Online docs ]
New functions are added to new PHP version.
The following functions are now native functions in PHP 8.1. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.
- array_is_list()
- enum_exists()
- fsync()
- fdatasync()
- imagecreatefromavif()
- imageavif()
- mysqli_fetch_column()
- sodium_crypto_core_ristretto255_add()
- sodium_crypto_core_ristretto255_from_hash()
- sodium_crypto_core_ristretto255_is_valid_point()
- sodium_crypto_core_ristretto255_random()
- sodium_crypto_core_ristretto255_scalar_add()
- sodium_crypto_core_ristretto255_scalar_complement()
- sodium_crypto_core_ristretto255_scalar_invert()
- sodium_crypto_core_ristretto255_scalar_mul()
- sodium_crypto_core_ristretto255_scalar_negate()
- sodium_crypto_core_ristretto255_scalar_random()
- sodium_crypto_core_ristretto255_scalar_reduce()
- sodium_crypto_core_ristretto255_scalar_sub()
- sodium_crypto_core_ristretto255_sub()
- sodium_crypto_scalarmult_ristretto255()
- sodium_crypto_scalarmult_ristretto255_base()
- sodium_crypto_stream_xchacha20()
- sodium_crypto_stream_xchacha20_keygen()
- sodium_crypto_stream_xchacha20_xor()
PHP 8.1 Removed Functions
[Since 2.3.0] - [ -P Php/Php81RemovedFunctions ] - [ Online docs ]
The following PHP native functions were deprecated in PHP 8.1, and will be removed in PHP 9.0.
- image2wbmp()
- png2wbmp()
- jpeg2wbmp()
- ldap_sort()
- hebrevc()
- convert_cyr_string()
- ezmlm_hash()
- money_format()
- get_magic_quotes_gpc()
- get_magic_quotes_gpc_runtime()
- create_function()
- each()
- read_exif_data()
- gmp_random()
- fgetss()
- restore_include_path()
- gzgetss()
Never Keyword
[Since 2.3.0] - [ -P Php/NeverKeyword ] - [ Online docs ]
Never becomes a PHP keyword. It is used for typing functions which never returns anything (either dies or throw an exception).
It should be avoided in namespaces, classes, traits and interfaces. Methods, constants and functions are OK.
<?php
// This is OK
function never() { }
// This is no OK
class never { }
?>
See also never and PHP RFC: noreturn type
Mixed Keyword
[Since 2.3.0] - [ -P Php/MixedKeyword ] - [ Online docs ]
Never becomes a PHP keyword. It is used for typing functions which never returns anything (either dies or throw an exception).
It should be avoided in classes, traits and interfaces. Methods, anonymous classes (sic), namespaces and functions are OK.
Setting a `never` class in a namespaces doesn't make it legit.
<?php
// This is OK
function never() { }
// This is no OK
class never { }
?>
See also and mixed
Mixed Typehint Usage
[Since 2.3.0] - [ -P Php/MixedUsage ] - [ Online docs ]
Usage of the mixed typehint.
<?php
function foo() : mixed {
switch(rand(0, 3)) {
case 0:
return false;
case 1:
return 'a';
case 2:
return [];
default:
return null;
}
}
?>
See also and Type declarations
False To Array Conversion
[Since 2.3.0] - [ -P Php/FalseToArray ] - [ Online docs ]
The auto vivification of false is deprecated. This feature is the automagical conversion of a boolean into an array, if needed.
<?php
$a = false;
//valid in PHP
$a[3] = 1;
?>
Until PHP 8.1, this was possible. This feature is deprecated in PHP 8.1, and will be removed in PHP 9.0.
See also and Autovivification from false
Float Conversion As Index
[Since 2.3.1] - [ -P Arrays/FloatConversionAsIndex ] - [ Online docs ]
Only integers and strings are possible types when used for array index. Until PHP 8.1, floats were converted to integer by truncation. Since PHP 8.1, a deprecated message is emitted.
The implicit conversion of float to int which leads to a loss in precision is now deprecated. This affects array keys, int type declarations in coercive mode, and operators working on integers.
<?php
$a = [];
$a[15.5]; // deprecated, as key value loses the 0.5 component
$a[15.0]; // ok, as 15.0 == 15
?>
See also and Implicit incompatible float to int conversions
Cannot Call Static Trait Method Directly
[Since 2.3.1] - [ -P Traits/CannotCallTraitMethod ] - [ Online docs ]
From the migration docs : Calling a static method, or accessing a static property directly on a trait is deprecated. Static methods and properties should only be accessed on a class using the trait.
<?php
trait t { static public function t() {}}
a::t();
// OK
t::t();
//Calling static trait method t::t is deprecated, it should only be called on a class using the trait
class a {
use t;
}
?>
See also and Calling a static element on a trait
Nested Attributes
[Since 2.3.1] - [ -P Attributes/NestedAttributes ] - [ Online docs ]
Nested attribute are attribute in attributes.
<?php
// Extracted from PHP 8.1 addendum (https://www.php.net/releases/8.1/en.php#new_in_initializers)
class User
{
#[\Assert\All(
new \Assert\NotNull,
new \Assert\Length(min: 6))
]
public string $name = '';
}
?>
Nested attributes are not available in PHP 8.0 and older. It is reported as an invalid constant expression.
See also PHP RFC: New in initializers and `New initializers`
New Initializers
[Since 2.3.1] - [ -P Php/NewInitializers ] - [ Online docs ]
Parameters, static variables and global constants may be initialized with an object.
<?php
function foo( $a = new A) {
static $static = new B;
}
const A = new C;
?>
This feature is available in PHP 8.1 and more recent. It is reported as an invalid constant expression in older PHP versions.
See also PHP RFC: New in initializers and `Nested Attributes`_
Deprecated Callable
[Since 2.3.1] - [ -P Functions/DeprecatedCallable ] - [ Online docs ]
Callable functions that are supported by call_user_func($callable) , but not with the $callable() syntax are deprecated.
One important aspect is the loss of context : 'self::method' may be created anywhere in the code, while `self::class` can only be used inside a class, and, in that case, inside the target class.
<?php
class x {
// This will fail
function foo(callable $callable) {
$callable();
}
function method() {
}
}
$x = new x;
$x->foo('self::method');
?>
It is recommended to update the code with any PHP version, to prepare for the future removal of the feature.
See also and PHP RFC: Deprecate partially supported callables
Promoted Properties
[Since 2.3.1] - [ -P Classes/PromotedProperties ] - [ Online docs ]
Promoted properties is a way to declare the properties within the constructor, and have them assigned to the constructing value at instantiation.
<?php
class CustomerDTO
{
public function __construct(
public string $name,
public string $email,
public DateTimeImmutable $birth_date,
) {}
}
?>
See also Constructor Promotion and PHP 8: Constructor property promotion
Overwritten Foreach Var
[Since 2.3.2] - [ -P Structures/OverwrittenForeachVar ] - [ Online docs ]
When using standard blind variable names, nested foreach may lead to overwriting the variables.
Careful coding may take advantage of that feature. Though, it tends to be error prone, and will generate bugs if the code is refactored.
<?php
foreach($array as $key => $value) {
foreach($array as $key2 => $value) {
// $value is now the one of the 2nd foreach, not the first.
}
}
?>
Checks Property Existence
[Since 2.3.3] - [ -P Classes/ChecksPropertyExistence ] - [ Online docs ]
This analysis reports checks property existence.
In PHP 8.2, non-specified properties are discouraged : they should always be defined in the class code. When this guideline is applied, properties always exists, and a call to property_exists() is now useless.
Some situations are still legit :
+ When the class is stdClass , where no property is initially defined. This may be the case of JSON data, or arrays cast to objects.
+ When the class uses magic methods, in particular __get(), __set() and __isset().
<?php
class x {
private $a = 1;
function foo() {
$this->cache = $this->a + 1;
}
}
?>
In this analysis, isset() and property_exists() are both used to detect this checking behavior. property_exists() is actually the only method to actually check the existence, since isset() will confuse non-existing properties and null .
While the behavior is deprecated in PHP 8.2, it is recommended to review older code and remove it. It will both ensure forward compatibility and cleaner, faster local code.
Extends stdClass
[Since 2.3.2] - [ -P Classes/ExtendsStdclass ] - [ Online docs ]
Those classes extends stdClass .
Traditionally, classes are defined independently, without any native class extension.
In PHP 8.2, dynamic properties are deprecated, and yield a warning in the logs. Adding 'extends \stdClass' to classes signature removes this warning, as stdclass is the empty class, without any method, property nor constants.
<?php
class myClass extends \stdClass {
function __set($a, $b) {
$this->$a = $b;
}
}
?>
Cant Overload Constants
[Since 2.3.2] - [ -P Interfaces/CantOverloadConstants ] - [ Online docs ]
It was not possible to overload class constants within a class, when the constant was defined in an interface.
<?php
interface i {
const A = 1;
}
//This lints, but doesn't executin in PHP 8.0 and older.
class x implements i {
const A = 1;
}
?>
See also and `interface constants
Intersection Typehint
[Since 2.3.3] - [ -P Php/Php81IntersectionTypehint ] - [ Online docs ]
Intersection typehints allows the combination of several typehint for the same argument or return value.
Several typehints are specified at the same place as a single one. The different values are separated by a ampersand character & .
<?php
class Number {
private A&B $object;
}
?>
Intersection types are a PHP 8.1 new feature.
See also PHP RFC: Pure intersection types, Type declarations and How the New Intersection Types in PHP 8.1 Give You More Flexibility
Recycled Variables
[Since 2.3.3] - [ -P Variables/RecycledVariables ] - [ Online docs ]
A recycled variable is used for two distinct missions in a method. There is usually a first
<?php
function foo() {
$variable = initial; // first initialisation
$variable = goo($variable); // processing the variable
hoo($variable); // sending the variable to a final destination
$variable = second ; // second initialisation
hoo2($variable); // sending the variable to a different final destination
}
?>
See also and Please Don’t Recycle Local Variables
Check Division By Zero
[Since 2.3.3] - [ -P Structures/CheckDivision ] - [ Online docs ]
Always check before dividing by a value. If that value is cast to 0, PHP might stop the processing with an exception, or keep processing it with 0 as a result. Both will raise problems.
The best practise is to check the incoming value before attempting the division. On possible alternative is to catch the DivisionByZeroError exception, that PHP 8.0 and more recent will raise.
<?php
// Check the value before usage
function foo($a = 1) {
if ($a !== 0) {
return 42 / $a;
} else {
// process an error
}
}
// Check the value after usage (worse than the above)
function foo($a = 1) {
try {
return 42 / $a;
} catch (DivisionByZero) {
// fix the situation now
}
}
// This might fails with a division by 0
function foo($a = 1) {
return 42 / $a;
}
?>
See also and DivisionByZeroError
Readonly Usage
[Since 2.3.5] - [ -P Classes/ReadonlyUsage ] - [ Online docs ]
Usage of the readonly option on class properties.
<?php
?>
See also and Readonly properties
Dont Reuse Foreach Source
[Since 2.3.5] - [ -P Structures/DontReuseForeachSource ] - [ Online docs ]
It is dangerous to reuse the same variable inside a loop that use it as a source.
PHP actually takes a copy of the source, so the foreach() loop is not affected by the modification. On the other hand, the source of the loop is modified after the loop (and actually, also during), which may come as a surprise to a later coder.
<?php
$properties = [];
foreach ($values as $i => $vars) {
// $values is used again here, now as a blind variable
foreach ($vars as $class => $values) {
foreach ($values as $name => $v) {
$properties[$class][$name][$i] = $v;
}
}
}
?>
Unreachable Method
[Since 2.3.6] - [ -P Classes/UnreachableMethod ] - [ Online docs ]
A method that is never called from the code.
The method has the following characteristics :
+ not private, aka public or protected
+ The direct class is never instantiated
+ All children classes overwrite this method
+ parent:: is never used to reach it
Then, this class is actually dead code.
<?php
class x {
protected function foox() {}
}
class xx extends x {
protected function foox() {}
}
?>
Unfinished Object
[Since 2.3.6] - [ -P Classes/UnfinishedObject ] - [ Online docs ]
Some of the properties are not assigned a value before or at constructor time. Then, they might be called when one of the other public method is called, and yield a fatal error.
<?php
class x {
private $p;
private $p2;
function __construct($p) {
$this->p = $p;
// $p2 is not assigned
}
function foo() {
$this->p->goo();
// This is not valid
$this->p2->goo();
}
}
?>
See also and Compulsory parameters should be required in your constructor
Use class_alias()
[Since 2.3.6] - [ -P Php/UseClassAlias ] - [ Online docs ]
class_alias() is a PHP features, that allows the creation of class alias, at execution time.
Those class aliases are application wide, as they are valid everywhere, yet they have a lower precedence over the use expression. This means that even when a class_alias() was called, the local use expression will have right of execution.
<?php
// static type of aliasing
use a as c;
class a {}
class_alias('a', 'b');
new b;
?>
See also and class_alias
Undefined Enumcase
[Since 2.3.6] - [ -P Enums/UndefinedEnumcase ] - [ Online docs ]
The enumeration case does not exists. It may also be a constant.
<?php
enum theEnum {
case A; // an enum case
// a constant
const C = 1;
}
function foo(theEnum $a) {}
foo(theEnum::A);
foo(theEnum::C);
?>
Dont Add Seconds
[Since 2.3.9] - [ -P Structures/DontAddSeconds ] - [ Online docs ]
Avoid adding seconds to a date, and use DateTime::modify to add an interval.
This method will handle situations like daylight savings, leap seconds and even leap days.
<?php
// Tomorrow, same time
$tomorrow = new DateTime('now')->modify('+1 day');
// Tomorrow, but may be not at the same hour
$tomorrow = date('now') + 86400;
?>
See also DateTime::modify and datetime
Use Constants As Returns
[Since 2.3.9] - [ -P Functions/UseConstantsAsReturns ] - [ Online docs ]
When a native PHP function returns only constants, it is recommended to use those constants to identify the returned values.
<?php
if (preg_last_error() != PREG_NO_ERROR ) {
// An error occured with the last Regex call
}
// Who will guess PREG_JIT_STACKLIMIT_ERROR ?
if (preg_last_error() == 6 ) {
// An error occured with the last Regex call
}
?>
Identical Variables In Foreach
[Since 2.3.9] - [ -P Structures/IdenticalVariablesInForeach ] - [ Online docs ]
Do not use the same variable names as a foreach() source and one of its blind variables.
Foreach() makes a copy of the original data while working on it : this prevents any interference. Yet, when the source and the blind variable is the same, the source will have changed after the loop.
<?php
// classic way to use a foreach loop
foreach($array as $key => $value) {
// doSomething with $key and $value
}
// unusual way to end up with a name conflict
foreach($a as $a => [$b, $c, $a]) {
// doSomething with $a and $a, $b, $c
}
// classic way to use a foreach loop
foreach($a as $a => $b) {
// doSomething with $a and $a
}
// Now, after the loop, $a is an integer or a string!
?>
Cant Overwrite Final Constant
[Since 2.3.9] - [ -P Classes/CantOverwriteFinalConstant ] - [ Online docs ]
A constant may be final, and can't be overwritten in a child class.
<?php
class y extends x {
const F = 1;
const P = 2;
}
class x {
final const F = 3;
private const PRI = 5; // Private can't be final
const P = 4;
}
?>
String Int Comparison
[Since 2.3.9] - [ -P Php/StringIntComparison ] - [ Online docs ]
While PHP allows direct comparison of integer and strings, with some type conversion, the rules of conversion changed in PHP 8.0. This lead to a change in behavior for comparison.
In particular, strings that are equal to 0, or empty strings, have changed.
This doesn't affect identity comparison, since the type is initially checked.
<?php
PHP 7 PHP 8
var_dump(0 == 0); true true
var_dump(0 == 0.0); true true
var_dump(0 == foo); false false
var_dump(0 > ''); false true
var_dump(0 < ''); false false
var_dump(0 >= ''); true true
var_dump(0 <= ''); true false?>
See also and String to Number Comparison
ext/protobuf
[Since 0.8.4] - [ -P Extensions/Extprotobuf ] - [ Online docs ]
Extension Protobuf.
Protocol Buffers (a.k.a., protobuf) are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data.
<?php
// Example extracted from https://developers.google.com/protocol-buffers/docs/reference/php-generated
// given a simple message
//message Foo {}
/*
The protocol buffer compiler generates a PHP class called Foo. This class inherits from a common base class, Google\Protobuf\Internal\Message, which provides methods for encoding and decoding your message types, as shown in the following example:
*/
$from = new Foo();
$from->setInt32(1);
$from->setString('a');
$from->getRepeatedInt32()[] = 1;
$from->getMapInt32Int32()[1] = 1;
$data = $from->serializeToString();
try {
$to->mergeFromString($data);
} catch (Exception $e) {
// Handle parsing error from invalid data.
...
}
?>
See also Protocol Buffers, PHP Protocol Buffers and protobuf-php on packagist
Unsupported Operand Types
[Since 1.7.2] - [ -P Structures/UnsupportedOperandTypes ] - [ Online docs ]
This error is raised when trying to combine an array and a scalar value.
Always checks that the types are compatible with the planned operations.
<?php
const MY_ARRAY = 'error';
// This leads to the infamous Unsupported operand types error
$b = MY_ARRAY + array(3,4);
?>
PHP detects this error at linting time, when using literal values. When static expression are involved, this error will appear at execution time.
See also and PHP - Fatal error: Unsupported operand types [duplicate]
version_compare Operator
[Since 2.3.1] - [ -P Php/VersionCompareOperator ] - [ Online docs ]
version_compare()'s third argument is checked for value. The third argument specifies the operator, which may be only one of the following : `<`, `lt`, `<=`, `le`, `>`, `gt`, `>=`, `ge`, `==`, `=`, `eq`, `!=`, `<>`, `ne`. The operator is case sensitive.
Until PHP 8.1, it was silently reverted to the default value. It is a deprecated warning in PHP 8.1 and will be finalized in PHP 9.0. It is recommended to fix this parameter in any PHP version.
<?php
// return true
var_dump(version_compare('2.0', '2.1', '<'));
// returns false
var_dump(version_compare('2.0', '2.1', '>'));
// returns NULL and might be interpreted as false
var_dump(version_compare('2.0', '2.1', 'as'));
?>
PHP 8.1 Resources Turned Into Objects
[Since 2.2.0] - [ -P Php/Php81RemovesResources ] - [ Online docs ]
Multiple PHP native functions now return objects, not resources. Any check on those values with is_resource() is now going to fail.
The affected functions are the following :
+ finfo_open()
+ ftp_connect()
+ imap_open()
+ ldap_connect()
+ ldap_list()
+ ldap_search()
+ ldap_first_entry()
+ ldap_next_entry ()
+ ldap_read()
+ pg_connect()
+ pg_pconnect()
+ pg_query()
+ pg_execute ()
+ pg_lo_create()
+ pspell_config_create()
+ pspell_new()
+ pspell_new_personal()
+ pspell_new_config()
See also and UPGRADING PHP 8.1
Do Not Cast To Int
[Since 0.10.6] - [ -P Php/NoCastToInt ] - [ Online docs ]
Do not cast floats values to int. Uses conversion functions like intval(), round(), floor() or ceil() to convert the value to integer, with known behavior.
Use functions like floor(), round() or ceil() : they use an explicit method for rounding, that helps keeping the side effects under control.
<?php
// echoes 7!
echo (int) ( (0.1 + 0.7) * 10 );
?>
See also and Integers
Constant Scalar Expression
[Since 0.8.4] - [ -P Php/ConstantScalarExpression ] - [ Online docs ]
Since PHP 5.6, it is possible to use expression with Constants and default values. One may only use simple operators.
<?php
const THREE = 1 + 2;
const ARRAY = array(1,2,3);
// dynamic version
define('ARRAY', array(1,2,3));
// constant scalar expression are available for default values
function foo($a = 1 + M_PI) {
}
?>
See also and New features.
Could Be Spaceship
[Since 2.4.0] - [ -P Structures/CouldBeSpaceship ] - [ Online docs ]
The spaceship operator compares values and returns 0 for equality, 1 for superior and -1 for inferior.
It is the same as below, and prevents lots of code.
<?php
if ($a) {
return 1;
} elseif ($b) {
return 0;
} else {
return -1;
}
?>
See also spaceship operator and Remembering what spaceship operator do on comparison in PHP
Sylius usage
[Since 2.4.0] - [ -P Vendors/Sylius ] - [ Online docs ]
This analysis reports usage of the Sylius framework.
Sylius is an Open Source Headless eCommerce Platform for mid-market and enterprise brands that need custom solutions.
<?php
declare(strict_types=1);
namespace App\Controller;
use Sylius\Bundle\ResourceBundle\Controller\ResourceController;
use Sylius\Component\Resource\ResourceActions;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
class ProductController extends ResourceController
{
public function showAction(Request $request): Response
{
$configuration = $this->requestConfigurationFactory->create($this->metadata, $request);
$this->isGrantedOr403($configuration, ResourceActions::SHOW);
$product = $this->findOr404($configuration);
// some custom provider service to retrieve recommended products
$recommendationService = $this->get('app.provider.product');
$recommendedProducts = $recommendationService->getRecommendedProducts($product);
$this->eventDispatcher->dispatch(ResourceActions::SHOW, $configuration, $product);
if ($configuration->isHtmlRequest()) {
return $this->render($configuration->getTemplate(ResourceActions::SHOW . '.html'), [
'configuration' => $configuration,
'metadata' => $this->metadata,
'resource' => $product,
'recommendedProducts' => $recommendedProducts,
$this->metadata->getName() => $product,
]);
}
return $this->createRestView($configuration, $product);
}
}
?>
See also and sylius
Dollar Curly Interpolation Is Deprecated
[Since 2.4.1] - [ -P Php/DeprecateDollarCurly ] - [ Online docs ]
Among the different variable interpolation is strings, ```` is deprecated. It is made obsolete in PHP 8.2, and should disappear in PHP 9.0.
There are still several interpolation ways : variables, array elements (one index-level) and curly brackets. It is also possible to use string concatenation.
<?php
$a = 'a';
$a2 = 'surprise!';
$b = $\{$a . 2};
echo $b;
// display 'surprise!'
?>
See also and https://wiki.php.net/rfc/deprecate_dollar_brace_string_interpolation
Unused Enumeration Case
[Since 2.4.0] - [ -P Enums/UnusedEnumCase ] - [ Online docs ]
Those are enumeration cases which are defined, yet not used.
<?php
enum x {
case A;
case C;
const F = 1;
}
function foo(x $a) {}
foo(x::A);
?>
The error message when the case is missing mentions the class constant : this is because enumeration cases and class constants use the same configuration. They are only distinguished by their definition, which, here, does not exists.
Useless Null Coalesce
[Since 2.4.0] - [ -P Structures/UselessNullCoalesce ] - [ Online docs ]
When the type system ensure the condition is never null, the operator becomes useless.
This is particularly true for properties (static or not) and returntype of methods and functions. And, to a lesser extend, to variables and parameters.
<?php
function foo(A $a, ?B $b) {
// $a is never null, so this is OK
$a ?? 'a';
// $b might be null, so this is OK
$b ?? 'b';
}
?>
See also and Null coalescing operator
Throw Raw Exceptions
[Since 2.4.0] - [ -P Exceptions/ThrowRawExceptions ] - [ Online docs ]
Avoid throwing native PHP exceptions. Consider defining specific and meaningful exception, by extending the native one.
<?php
// Throwing a raw exception
throw new exception('This is an error!');
class myException extends Exception {}
throw new myException('This is a distinguished error!');
?>
Thanks to Atif Shahab Qureshi for the inspiration.
See also and Stop using regular exceptions in PHP!
Extensions yar
[Since 2.4.1] - [ -P Extensions/Extyar ] - [ Online docs ]
yar : Yet Another RPC framework.
<?php
/* assume this page can be accessed by http://example.com/operator.php */
class Operator {
/**
* Add two operands
* @param interge
* @return interge
*/
public function add($a, $b) {
return $this->_add($a, $b);
}
/**
* Sub
*/
public function sub($a, $b) {
return $a - $b;
}
/**
* Mul
*/
public function mul($a, $b) {
return $a * $b;
}
/**
* Protected methods will not be exposed
* @param interge
* @return interge
*/
protected function _add($a, $b) {
return $a + $b;
}
}
$server = new Yar_Server(new Operator());
$server->handle();
?>
Implicit Conversion To Int
[Since 2.4.2] - [ -P Structures/ImplicitConversionToInt ] - [ Online docs ]
PHP warns when a value is implicitely converted from float to int. This usually leads to a loss of precision and unexpected values.
The conversion happens in various situations in PHP lifecycle (extracted from the wiki article):
+ Bitwise OR operator |
+ Bitwise AND operator &
+ Bitwise XOR operator ^
+ Shift right and left operators
+ Modulo operator
+ The combined assignment operators of the above operators
+ Assignment to a typed property of type int in coercive typing mode
+ Argument for a parameter of type int for both internal and custom functions in coercive typing mode
+ Returning such a value for custom functions declared with a return type of int in coercive typing mode
+ Bitwise NOT operator ~
+ As an array key
<?php
function foo(int $i) {}
//Implicit conversion from float 1.2 to int loses precision
foo(1.2);
?>
This features is applied to PHP 8.1 and later, yet it is also applicable to older versions of PHP.
See also and PHP RFC: Deprecate implicit non-integer-compatible float to int conversions
Excimer
[Since 2.4.2] - [ -P Extensions/Extexcimer ] - [ Online docs ]
Excimer is a PHP 7.1+ extension that provides an interrupting timer and a low-overhead sampling profiler.
<?php
$timer = new ExcimerTimer;
$timer->setInterval( 10 /* seconds */ );
$timer->setCallback( function () {
throw new Exception( The allowed time has been exceeded );
} );
$timer->start();
do_expensive_thing();
?>
See also and Excimer
Use Same Types For Comparisons
[Since 2.4.2] - [ -P Structures/UseSameTypesForComparisons ] - [ Online docs ]
Beware when using inequality operators that the type of the values are the same on both sites of the operators.
Different types may lead to PHP type juggling, where the values are first cast to one of the used types. Other comparisons are always failing, leading to unexpected behavior.
This applies to all inequality operators, as well as the spaceship operator.
<?php
// Both are wrong, while one should be true (depending on when you read this)
var_dump('1995-06-08' < new DateTimeImmutable());
var_dump('1995-06-08' > new DateTimeImmutable());
enum x : int {
case A = 1;
case B = 2;
}
// Both are false as objects are compared, not their integer value
var_dump(x::A < x::B);
var_dump(x::A > x::B);
var_dump(x::A->value < x::b->value);
var_dump(x::A->value > x::b->value);
?>
This analysis skips comparisons between integers, floats and strings, as those are usually expected.
Thanks to Jordi Boggiano and Filippo Tessarotto.
Wrong Locale
[Since 2.4.2] - [ -P Structures/WrongLocale ] - [ Online docs ]
Checks the locale used in the code against a library.
<?php
// what language ?
setLocale(LC_ALL, 'hx');
// utf8 actually needs a - : utf-8
setLocale(LC_ALL, 'utf8');
?>
ext/pkcs11
[Since 2.4.2] - [ -P Extensions/Extpkcs11 ] - [ Online docs ]
In cryptography, PKCS #11 is one of the Public-Key Cryptography Standards. This extensions provides methods to create, read and check those keys.
<?php
$key = $session->generateKey(new Pkcs11\Mechanism(Pkcs11\CKM_AES_KEY_GEN), [
Pkcs11\CKA_CLASS => Pkcs11\CKO_SECRET_KEY,
Pkcs11\CKA_SENSITIVE => true,
Pkcs11\CKA_ENCRYPT => true,
Pkcs11\CKA_DECRYPT => true,
Pkcs11\CKA_VALUE_LEN => 32,
Pkcs11\CKA_KEY_TYPE => Pkcs11\CKK_AES,
Pkcs11\CKA_LABEL => Test AES,
Pkcs11\CKA_PRIVATE => true,
]);
?>
ext/spx
[Since 2.4.2] - [ -P Extensions/Extspx ] - [ Online docs ]
SPX, which stands for Simple Profiling eXtension, is just another profiling extension for PHP.
<?php
while ($task = get_next_ready_task()) {
spx_profiler_start();
try {
$task->process();
} finally {
spx_profiler_stop();
}
}
?>
See also and `
Parent Is Not Static
[Since 2.4.3] - [ -P Classes/ParentIsNotStatic ] - [ Online docs ]
The `parent` keyword behaves like `self`, not like `static`. It links to the parent of the defining expression, not to the one being called.
This may skip the parent of the calling class, and create a `Undefined method` call, or yield the wrong `::class` value. It may also skip a local version of the method.
<?php
class w {
}
class x extends w {
function foo() {
parent::method();
}
// method() is in the parent of Y, but not in the one of X.
function method() {
print __METHOD__;
}
}
class y extends x {}
(new y)->foo();
// print W::method
(new y)->method();
// print x::method
?>
No Magic Method For Enum
[Since 2.4.2] - [ -P Enums/NoMagicMethod ] - [ Online docs ]
Enumeration cannot have a magic method, nor a constructor.
<?php
enum a {
function __construct($a) {}
}
?>
See also and Enumeration Methods
No Readonly Assignation In Global
[Since 2.4.2] - [ -P Classes/NoReadonlyAssignationInGlobal ] - [ Online docs ]
When a property is marked readonly, it may only be assigned within the class of definition.
It cannot be assigned outside this class, in the global scope. It is also immune to class invasion.
<?php
class x {
public readonly int $p;
function foo() {
$this->p -= 1; // OK
$x = new x;
$x->p = 1; // Not OK, even if $x is of type x
}
}
$x = new x;
$x->p = 1; // Not OK
?>
Stomp
[Since 2.4.2] - [ -P Extensions/Extstomp ] - [ Online docs ]
This extension allows php applications to communicate with any Stomp compliant Message Brokers through easy object-oriented and procedural interfaces.
<?php
$queue = '/queue/foo';
$msg = 'bar';
/* connection */
try {
$stomp = new Stomp('tcp://localhost:61613');
} catch(StompException $e) {
die('Connection failed: ' . $e->getMessage());
}
/* send a message to the queue 'foo' */
$stomp->send($queue, $msg);
/* subscribe to messages from the queue 'foo' */
$stomp->subscribe($queue);
/* read a frame */
$frame = $stomp->readFrame();
if ($frame->body === $msg) {
var_dump($frame);
/* acknowledge that the frame was received */
$stomp->ack($frame);
}
/* close connection */
unset($stomp);
?>
See also and Stomp
ext/CSV
[Since 2.4.2] - [ -P Extensions/Extcsv ] - [ Online docs ]
A small PHP extension to add/improve the handling of CSV strings.
<?php
$fields = [
'Hello',
'World',
];
$output = Hello,World;
var_dump($output === CSV::arrayToRow($fields));
var_dump(CSV::rowToArray($output));
?>
See also and PHP csv extension
Overload Existing Names
[Since 2.4.2] - [ -P Namespaces/OverloadExistingNames ] - [ Online docs ]
Imported alias have precedence over existing ones, and as such, may replace existing features with unexpected ones.
This example shows how to replace strtolower() with strtoupper() while keeping the main code intact. This might be very confusing code.
<?php
// Replacing a PHP classic with another one
use function strtoupper as strtolower;
echo strtolower('pHp');
// displays PHP
?>
This behavior is important for backward compatibility, and also to avoid naming conflicts when the coding has been done with a PHP installation which do not have some specific declaration. For example, a source may define an 'Event' class, which will be in conflict when the ext/event library is installed.
This feature is also useful to mock some native PHP structures, during tests.
This rule relies on the PDFF configuration to check for external existing structures.
Array Addition
[Since 2.4.2] - [ -P Structures/ArrayAddition ] - [ Online docs ]
Addition where one of the operands are arrays.
<?php
$a = [1] + [2 ,3];
?>
See also Combining arrays using + versus array_merge in PHP and Array operators
Retyped Reference
[Since 2.4.3] - [ -P Functions/RetypedReference ] - [ Online docs ]
A parameter with a reference may be typed differently, at the end of a method call.
It is possible for a referenced and typed parameter to be retyped during a method call. As such, the type of the used variable might both be checked and changed.
Using such syntax will lead to confusion in the code.
<?php
$a = [1];
foo($a);
echo $a; // Now, $a is a string
function foo(array &$a) {
$a = Now, I am a string;
}
?>
This works on all types, scalars or objects.
This rule will detect variables which are defined with a placeholder value, or even undefined, and are filled during the method call.
Wrong Type With Default
[Since 2.4.4] - [ -P Typehints/WrongTypeWithDefault ] - [ Online docs ]
The default value is not of the declared type.
For properties, this will generate an error as soon as the default value is used : this is before constructor call for properties, and when the argument is omitted for promoted properties.
For parameters, the error happens when the argument is omitted, and the default value is fetched. Otherwise, it won't happen.
<?php
const A = 1;
class B {
private string $c = A;
}
new B;
//Cannot assign string to property B::$c of type string
?>
This error is immediately detected when a literal value is used. It only happens when the default is a constant (class or global) or an expression, as those are only solved at execution time.
See also and When does PHP check for Fatal error
Ice framework
[Since 2.4.4] - [ -P Extensions/Extice ] - [ Online docs ]
Ice - simple, fast and open-source PHP framework frozen in C-extension.
See also ice framework and ice framework : Hello world tutorial
Extensions/Exttaint
[Since 2.4.4] - [ -P Extensions/Exttaint ] - [ Online docs ]
Taint is a extension used to detect and track tainted string. It follows each assignation of the code and keeps track of its taint. And also can be used to spot sql injection vulnerabilities, shell inject, etc.
<?php
$a = trim($_GET['a']);
$file_name = '/tmp' . $a;
$output = "Welcome, {$a} !!!";
//Warning: main() [function.echo]: Attempt to echo a string that might be tainted
?>
See also taint and taint on github
Sprintf Format Compilation
[Since 2.4.5] - [ -P Structures/SprintfFormatCompilation ] - [ Online docs ]
The sprintf() format used yields an error.
This applies to printf(), sprintf(), vprintf(), vfprintf(), vsprintf(), sscanf(), fscanf()
<?php
printf('%we3e', 123);
//Unknown format specifier
?>
See also and sprintf
Invalid Date Scanning Format
[Since 2.4.5] - [ -P Structures/InvalidDateScanningFormat ] - [ Online docs ]
The format string used with Datetime::createFromFormat() method (or similar) contains unknown characters.
This won't raise an error, though the resulting values should be checked.
<?php
// format is valid
$date = datetimeimmutable::createFromFormat('d/m/Y', $a);
// When wrong, $date is false
// The errors are in datetimeimmutable::getLastErrors();
// X is not a valid character for
$date = datetimeimmutable::createFromFormat('d/X/Y', $a);
?>
Same Name For Property And Method
[Since 2.4.5] - [ -P Classes/PropertyMethodSameName ] - [ Online docs ]
A property and a method have the same name. While it is a valid naming scheme with PHP, it may lead to confusion while codeing.
Such naming collision may appear with words that are the same as a verb (for method) and as a noun (for property). For example, in English : query, work, debug, run, process, rain, polish, paint, etc,.
It may also happen during the life cycle of the class, as it is extended with new methods and properties, and little care is give to semantic meaning of the names, beyond the task at hand.
<?php
class x {
public $foo;
function foo() {}
}
$x = new X:
$x->p = $x->foo();
?>
It is recommended to avoid those collisions, and keep properties and methods named distinctly.
That problem do not happen to constants, which are mostly written uppercase. This rule is case-insensitive.
See also and Words That Are Both Nouns And Verbs
Utf8 Encode And Decode Are Deprecated
[Since 2.4.5] - [ -P Php/Utf8EncodeDeprecated ] - [ Online docs ]
utf8_encode() and utf8_decode() are deprecated in PHP 8.0. They are planned removal in PHP 9.0.
See also and PHP RFC: Deprecate and Remove utf8_encode and utf8_decode
DateTimeImmutable Is Not Immutable
[Since 2.4.5] - [ -P Php/DateTimeNotImmutable ] - [ Online docs ]
DateTimeImmutable is not really immutable because its internal state can be modified after instantiation.
<?php
$dt = new DateTimeImmutable('now');
echo $dt->getTimestamp() . \n;
$dt->__construct('tomorrow');
echo $dt->getTimestamp() . \n;
?>
Inspired by the article from Matthias Noback .
See also and Effective immutability with PHPStan
New Functions In PHP 8.2
[Since 2.3.0] - [ -P Php/Php82NewFunctions ] - [ Online docs ]
New functions are added to new PHP version.
The following functions are now native functions in PHP 8.2. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.
- curl_upkeep()
- mysqli_execute_query()
- odbc_connection_string_is_quoted()
- odbc_connection_string_should_quote()
- odbc_connection_string_quote()
- ini_parse_quantity()
- memory_reset_peak_usage()
- sodium_crypto_stream_xchacha20_xor_ic()
No Default For Referenced Parameter
[Since 2.4.7] - [ -P Functions/NoDefaultForReference ] - [ Online docs ]
Parameters with reference should not have a default value.
When they have a default value, that default value is not a reference, and it will not have impact on the calling context.
Then, the parameter behaves like a reference when the argument is provided, and not as a reference when the parameter is not provided. This makes sense : no parameter in, no parameter out.
<?php
function foo(&$i = 1) {
++$i;
}
// $i is 1, but it is not available in the calling context
foo();
// $i is 1, but it is not available in the calling context
$i = 1;
foo($i);
echo $i; // $i is now 2
?>
Clone Constant
[Since 2.4.7] - [ -P Php/CloneConstant ] - [ Online docs ]
Cloning constant is only possible since PHP 8.1. Until that version, constants could not be an object, and as such, could not be cloned.
This is also valid with default values, however they are assigned to a variable, which falls back to the classic clone usage.
Backward compatibility is OK, since PHP compile such code, and only checks at execution time that the constant is an object.
<?php
// new is available in constant definition, since PHP 8.2
const A = new B();
$c = clone A;
?>
See also and New in initializers
Random extension
[Since 2.4.7] - [ -P Extensions/Extrandom ] - [ Online docs ]
The random extension. It improves the random generators from the older PHP version, and provides a OOP interface.
<?php
$rng = $is_production
? new Random\Engine\Secure()
: new Random\Engine\PCG64(1234);
$randomizer = new Random\Randomizer($rng);
$randomizer->shuffleString('foobar');
?>
See also and PHP RFC: Random Extension 5.x
Ip
[Since 2.4.7] - [ -P Type/Ip ] - [ Online docs ]
List of IP in hardcode in the source.
See also and IP converter
Could Inject Param
[Since 2.4.7] - [ -P Classes/CouldInjectParam ] - [ Online docs ]
The parameter is directly used to create an object. It could be interesting to replace it with an injection of that object's type to keep the method generic.
<?php
class x {
// The directory is immediately injected
function foo(Directory $dir) {
$this->dir = $dir;
}
// Path is injected, then turned into a directory
function bar(string $path) {
$this->dir = new Directory($path);
}
}
?>
ext/scrypt
[Since 2.4.7] - [ -P Extensions/Extscrypt ] - [ Online docs ]
This is a PHP library providing a wrapper to Colin Percival's scrypt implementation. Scrypt is a key derivation function designed to be far more secure against hardware brute-force attacks than alternative functions such as PBKDF2 or bcrypt.
<?php
echo scrypt(, , 16, 1, 1, 64) . \n;
echo scrypt(password, NaCl, 1024, 8, 16, 64) . \n;
?>
See also `scrypt
ext/teds
[Since 2.4.8] - [ -P Extensions/Extteds ] - [ Online docs ]
teds (Tentative Extra Data Structures) is a collection of data structures and iterable functionality.
See also and PECL TEDS
Geospatial
[Since 2.4.7] - [ -P Extensions/Extgeospatial ] - [ Online docs ]
PHP Extension to handle common geospatial functions. The extension currently has implementations of the Haversine and Vincenty's formulas for calculating distances, an initial bearing calculation function, a Helmert transformation function to transfer between different supported datums, conversions between polar and Cartesian coordinates, conversions between Degree/Minute/Seconds and decimal degrees, a method to simplify linear geometries, as well as a method to calculate intermediate points on a LineString.
<?php
$from = array(
'type' => 'Point',
'coordinates' => array( -104.88544, 39.06546 )
);
$to = array(
'type' => 'Point',
'coordinates' => array( -104.80, 39.06546 )
);
var_dump(haversine($to, $from));
?>
NB : description and exemples are extracted from the extension source code.
See also and `geospatial - PHP Geospatial Extension
Feast usage
[Since 2.4.8] - [ -P Vendors/Feast ] - [ Online docs ]
This analysis reports usage of the Feast framework.
FEAST is a radically different PHP Framework that was built from the ground up to be an alternative to the dependency-heavy frameworks that exist already. Its goal is a light-weight footprint that just lets you get stuff done.
<?php
$this->httpRequest->postJson(self::URL . '/subscribers');
$this->httpRequest->addArguments($data);
$this->httpRequest->authenticate($this->apiKey, '');
$this->httpRequest->makeRequest();
$response = $this-httpRequest->getResponseAsJson();
?>
See also Feast and `Feast on github
date() versus DateTime Preference
[Since 2.4.9] - [ -P Structures/DateTimePreference ] - [ Online docs ]
Processing dates is done with date() functions or DateTime classes.
In the date() team, there are the following functions : date(), time(), getdate(), localtime(), strtotime(), strptime(), gmdate(), strftime(), mktime(), gmktime().
In the DateTime team, there are the instantiation of DateTime and DateTimeImmutable; the DateTime::createFromInterface(), DateTime::createFromFormat(), DateTime::createFromImmutable() and DateTime::createFromMutable().
The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.
<?php
// be consistent
$date = date();
$time = time();
$date = date();
$time = time();
$date = date();
$time = time();
$date = date();
$time = time();
$date = date();
$time = time();
$date = date();
$time = time();
// Be consistent, always use the same.
$date = new DateTime();
?>
Unused Public Method
[Since 2.4.9] - [ -P Classes/UnusedPublicMethod ] - [ Online docs ]
List unused public methods.
Mbstring Unknown Encodings
[Since 2.5.0] - [ -P Structures/MbStringNonEncodings ] - [ Online docs ]
mbstring functions require one of its supported encoding as parameter.
For example, mb_chr() requires encoding as second parameter. The supported encodings are available with mb_list_encodings() and mb_encoding_aliases().
A wrong encoding generates a fatal error.
<?php
print mb_chr(128024, 'UTF-8')); // emoji of an elephant
//Argument #2 ($encoding) must be a valid encoding, elephpant given
print mb_chr($value, 'elephpant'));
}
?>
Here are some of the dropped encodings, depending on PHP versions:
+ PHP 7.0
+ auto
+ PHP 8.0
+ pass
+ PHP 8.1
+ wchar
+ byte2be
+ byte2le
+ byte4be
+ byte4le
+ jis-ms
+ cp50220raw
+ PHP 8.2
+ qprint
+ base64
+ uuencode
+ html-entities
Named Argument And Variadic
[Since 2.5.0] - [ -P Php/NamedArgumentAndVariadic ] - [ Online docs ]
Variadic argument must be the last in the list of arguments. Since PHP 8.1, it is possible to use named arguments after a variadic argument.
<?php
// named arguments may be after the variadic
foo(...$a, a: 1);
// positional arguments MUST be before the variadic
foo(...$a, 1);
// Normal way
foo( 1, ...$a);
?>
Coalesce And Ternary Operators Order
[Since 2.5.0] - [ -P Structures/CoalesceNullCoalesce ] - [ Online docs ]
The ternary operator and the null-coalesce operator cannot be used in any order. The ternary operator is wider, so ot should be used last.
In particular, the ternary operator works on truthy values, and NULL is a falsy one. So, NULL might be captured by the ternary operator, and the following coalesce operator has no chance to process it.
On the other hand, the coalesce operator only process NULL, and will leave the false (or any other falsy value) to process to the ternary operator.
<?php
// Good order : NULL is processed first, otherwise, false will be processed.
$b = $a ?? 'B' ?: 'C';
// Wrong order : this will never use the ??
$b = $a ?: 'C' ?? 'B';
?>
Useless Assignation Of Promoted Property
[Since 2.5.0] - [ -P Classes/UselessAssignationOfPromotedProperty ] - [ Online docs ]
Promoted properties save the assignation of constructor argument to the property. It is useless to do it with that syntax, and in the constructor too.
<?php
class x {
private $b;
function __construct(private $a,
$b,
) {
// This is already done with the promoted property
$this->a = $a;
// This is the traditional way (up to PHP 8.0)
$this->b = $b;
}
}
?>
Empty Loop
[Since 2.5.0] - [ -P Structures/EmptyLoop ] - [ Online docs ]
Empty loop may come from a typo, where a semi colon detach the block from its loop.
<?php
$i = 0;
// sneaky ;
while($i < 10) ; {
$i++;
}
// another sneaky semicolon
foreach($a as $b) ;
{
$i++;
}
?>
Useless Method
[Since 2.5.1] - [ -P Classes/UselessMethod ] - [ Online docs ]
This method is useless, as it actually does what PHP would do by default.
<?php
class y {
function foo() {
// doSomething('foo')
}
function goo() {
// doSomething('goo')
}
}
class x extends y {
// No definition for goo(), so it fallback to the parent
// This definition of foo() falls back to the parent's,
// just like if it wasn't there.
function foo() {
return parent::foo();
}
}
?>
Weak Type With Array
[Since 2.5.1] - [ -P Arrays/WeakType ] - [ Online docs ]
Using array as a type, to use specific index later.
The type of array is too weak : it allows to know that the array syntax has to be used in the function. Yet, it doesn't enforce the presence or absence of a specific index.
<?php
function foo(array $variable) {
echo $array['display'];
}
?>
See also Stop using Arrays and Never* Use Arrays
Multiple Type Cases In Switch
[Since 2.5.1] - [ -P Structures/MultipleTypeCasesInSwitch ] - [ Online docs ]
This reports switch() instructions, which have several types in cases.
This might generate compatibility errors, as the comparison may succeed in different ways, depending on PHP versions. This is particularly the case for PHP 8.0, and values such as '0', '', 0, null, and false.
<?php
switch($a) {
case 1:
break;
case 'a':
break;
}
?>
This situation doesn't affect match(), as it uses a strict type comparison, unlike switch().
Plus Plus Used On Strings
[Since 2.5.1] - [ -P Php/PlusPlusOnLetters ] - [ Online docs ]
Reports strings that are incremented.
This spots issues of the famous feature of PHP :
<?php
$a = 'a';
$a++;
print $a;
// prints b
?>
This analysis checks for string to be incremented. It doesn't check if the string is a numeric string, but does check the type, implicit or explicit.
See also Incrementing/Decrementing Operators and Path to Saner Increment/Decrement operators
No Max On Empty Array
[Since 2.5.2] - [ -P Structures/NoMaxOnEmptyArray ] - [ Online docs ]
Using max() or min() on an empty array leads to a valueError exception.
Until PHP 8, max() and min() would return null in case of empty array. This might be confusing with actual values, as an array can contain null . null has a specific behavior when comparing with other values, and should be avoided with max() and sorts.
<?php
// Throws a value error
$a = max([]);
$array = [];
if (empty($array)) {
$a = null;
} else {
$a = max($array);
}
var_dump(min([-1, null])); // NULL
var_dump(max([-1, null])); // -1
var_dump(max([1, null])); // 1
?>
Until PHP 8.0, a call on an empty array would return null, and a warning.
No Empty String With explode()
[Since 2.5.2] - [ -P Structures/NoEmptyStringWithExplode ] - [ Online docs ]
explode() doesn't allow empty strings as separator. Until PHP 8.0, it would make a warning, and return false. After that version, it raises a ValueError.
To break a string into individual characters, it is possible to use the array notation on strings, or to use the str_split() function.
<?php
explode('', a);
?>
Double Checks
[Since 2.5.2] - [ -P Structures/DoubleChecks ] - [ Online docs ]
Double checks happen when data is checked at one point, and then, checked again, with the same test, in a following call.
Some of the testing may be pushed to the type system, for example is_int() and int type. Others can't, as the check is not integrated in the type system, such as is_readable() and string , for a path.
The check may be removed from the method, when the method is not called elsewhere without protection.
<?php
if (is_writeable($path)) {
foo($path);
}
function foo(string $path) {
// This was already tested
if (!is_writeable($path)) {
return;
}
}
?>
Cleaning such structure leads to micro-optimisation.
strpos() With Integers
[Since 2.5.2] - [ -P Php/StrposWithIntegers ] - [ Online docs ]
strpos() used to accept integer as second argument, and turn them into their ASCII equivalent. This was deprecated in PHP 7.x, and dropped in 8.0.
<?php
strpos('abc ', 32);
// PHP 8.0+ : false, 32 is not found
// PHP 7.4- : 3, 32 is turned into space, then found
?>
It is recommended to use casting to ensure the variable is actually strings, and strpos() behaves as expected.
Missing Assignation In Command
[Since 2.5.2] - [ -P Structures/MissingAssignation ] - [ Online docs ]
A variable is assigned in one of the branch, but not the other. Such variable might be needed later, and not available.
elseif() and branches that returns or goto somewhere else are omitted.
This is work in progress.
<?php
if ($condition) {
$a = 1;
$b = 2;
} else {
$a = 3;
}
// $b might be missing
?>
Short Ternary
[Since 2.5.2] - [ -P Php/ShortTernary ] - [ Online docs ]
Short ternaries are the ternary operator, where the middle operand was left out.
Written that way, the operator checks if the first operand is empty() : in that case, the second operand is used; Otherwise, the first operand is used.
<?php
// $b is now 2
$b = $a ?: 2;
// $c is now 2 also
$c = $b ?: 4;
?>
See also and Ternary Operator
Deprecated Mb_string Encodings
[Since 2.5.2] - [ -P Structures/DeprecatedMbEncoding ] - [ Online docs ]
Some encodings, available in the mb_string extensions, are deprecated. Starting with PHP 8.2, the following encodings emits a warning:
+ BASE64
+ UUENCODE
+ HTML-ENTITIES
+ html
+ Quoted-Printable
+ qprint
This applies to the mb_detect_encoding() and mb_convert_encoding() functions.
<?php
// recommended version
$base64Encoded = base64_encode('test'));
// Deprecated version
mb_convert_encoding('test', 'base64'));
?>
See also and PHP 8.2: Mbstring: Base64, Uuencode, QPrint, and HTML Entity encodings are deprecated
No Valid Cast
[Since 2.5.2] - [ -P Structures/NoValidCast ] - [ Online docs ]
This cast generates an error, as there is no way to convert an object to an int.
The result will be 1.
<?php
$a = (int) foo();
function foo() : A {}
?>
This rule applies to float and int. This doesn't apply to string cast, as the magic method __toString() allows for such conversions.
Misused Yield
[Since 2.5.2] - [ -P Structures/MisusedYield ] - [ Online docs ]
When chaining generator, one must use the yield from keyword.
Forgetting the yield from keyword cancels the generator nature of the functioncall and nothing is emited.
Using yield on a generator, yields ... the generator, not the values of the generator.
<?php
function foo() {
yield 1;
// Goo is called, but not run as a generator
goo();
}
function hoo() {
yield 1;
// Goo is yield, but not run as a generator
yield goo();
}
function goo() {
yield 3;
}
?>
It is legit to yield a generator, for later usage. This is just very uncommon, and worth a check.
Use DNF
[Since 2.5.3] - [ -P Php/UseDNF ] - [ Online docs ]
This rule detects the usage of the DNF. DNF is the disjunctive Normal Form. It is a syntax to handle union and intersectional types at the same time. It was introducted in PHP 8.2.
DNF is available for every typed element of PHP : properties, arguments and returntype.
<?php
function foo((A&B)|(C&D) $e) {}
?>
See also and PHP 8.2: DNF Types
No Null For Index
[Since 2.5.3] - [ -P Structures/NoNullForIndex ] - [ Online docs ]
Avoid using null value as an index in an array. PHP actually cast it to the empty string. This means that later, it might be impossible to find the null in the list of keys.
<?php
$a = [];
$a[null] = 1;
print_r(array_keys($a));
// [''] empty string
?>
Useless Try
[Since 2.5.3] - [ -P Exceptions/UselessTry ] - [ Online docs ]
Report try clause that are useless. A try clause is useless when no exception is emitted by the code in the block.
<?php
try {
// Nothing is going to happen here
++$a;
} catch (Exception $e) {
}
?>
This happens when the underlying layers removed the emission of exceptions.
Converted Exceptions
[Since 2.5.3] - [ -P Exceptions/ConvertedExceptions ] - [ Online docs ]
Converted exceptions is when an exception is caught, then immediately converted into another one and thrown again.
Sometimes, extra operations take place, such as logging or error couting.
<?php
try {
doSomething();
} catch (MyException $e) {
log($e->getMessage());
throw new BadRequestException();
}
?>
Method Is Not An If
[Since 2.5.3] - [ -P Functions/MethodIsNotAnIf ] - [ Online docs ]
When a method consists only in one if statement, it might be worth refactoring.
Each of the blocks of the if/then structure may be turned into their own method, so has to keep operations distinct.
Then, the condition can be used as part of a larger method.
<?php
function foo($a) {
if ($a === 1) {
return 1;
} else {
return 2;
}
}
?>
Default Then Discard
[Since 2.5.3] - [ -P Structures/DefaultThenDiscard ] - [ Online docs ]
Discard the value before assigning it.
In the code below, the variable is assigned a default value. Then, this value is immediately tested and discarded.
It is more readable to test the value, and discard it, or assign it later, rather than assign first then discard it later.
<?php
$a = $a ?? null;
if ($a === null) {
throw new Exception();
}
doSomething();
// Alternative code
if (!isset($a) || $a === null) {
throw new Exception();
}
// $a has a valid value for the purpose
doSomething();
?>
Identical Case In Switch
[Since 2.5.3] - [ -P Structures/IdenticalCase ] - [ Online docs ]
In a switch() or match() statement, when there are identical cases, it means that multiple case labels that have the same code block.
This can happen by mistake or design. They may be merged together.
<?php
switch($a) {
case 1:
$b = 2;
break;
case 2:
$b = 12;
break;
// Identical to case 1
case 3:
$b = 2;
break;
}
?>
StandaloneType True False Null
[Since 2.5.3] - [ -P Typehints/StandaloneTypeTFN ] - [ Online docs ]
Report usage of standalone types of true, false and null.
false and null were added to PHP in PHP 8.2, as standalone types : they can be used alone in a type declaration (property, argument or returntype). true was added in PHP 8.3.
<?php
// simplistic example
function foo(true $t) : false {
return false;
}
?>
See also and What's the 'true' Standalone Type in PHP?
Constants In Traits
[Since 2.5.3] - [ -P Traits/ConstantsInTraits ] - [ Online docs ]
Trait may have their own constants. This was introduced in PHP 8.2.
trait t {
const A = 1;
}
See also PHP RFC: Constants in Traits and Ability to use Constants in Traits in PHP 8.2
Could Use Yield From
[Since 2.5.3] - [ -P Structures/CouldUseYieldFrom ] - [ Online docs ]
Yield from replaces a loop and a yield call. The resulting syntax is shorter and faster.
<?php
foreach(foo() as $f) {
doSomething($f);
}
// using yield and a loop to yield all elements
function foo() {
foreach(goo() as $g) {
yield $g;
}
}
// using yield from to yield all elements
function foo2() {
yield from goo();
}
function goo() : array {
return [1,2,3];
}
?>
Use Enum Case In Constant Expression
[Since 2.5.3] - [ -P Php/UseEnumCaseInConstantExpression ] - [ Online docs ]
Enum cases are constants, and may be used in constant definitions, as value. This is valid both with the case itself, or with their value, for the backed enum version.
<?php
enum A {
case A;
}
enum B : string {
case B = 'b';
}
class C {
const C1 = A::A;
const C2 = B::B->value;
}
?>
Readonly Property Changed By Cloning
[Since 2.5.3] - [ -P Php/ReadonlyPropertyChangedByCloning ] - [ Online docs ]
Readonly properties may be changed when cloning. This may happen in the __clone magic method.
In that method, a new object is being created. It is acting like a constructor, and may tweak some of the values of the original object, before assigning them to the new object.
<?php
class x {
public readonly int $p;
function __construct($p) {
$this->p = $p;
}
function __clone() {
// This is possible in a clone, and only once
$this->p = $this->p + 1;
// This second call is not possible, as the property was set just above
$this->p = $this->p + 2;
}
}
$a = new x(1);
print_r(clone $a);
?>
New Dynamic Class Constant Syntax
[Since 2.5.3] - [ -P Classes/NewDynamicConstantSyntax ] - [ Online docs ]
There is a dedicated syntax to access dynamically to class constant values.
<?php
class x {
const A = 1;
}
$a = 'A';
echo x::{$a}; // displays 1
?>
class_alias() Supports Internal Classes
[Since 2.5.3] - [ -P Php/ClassAliasSupportsInternalClasses ] - [ Online docs ]
class_alias() accepts internal classes as first argument. Until PHP 8.3, this feature was restricted to user-defined classes.
<?php
class_alias(stdClass::class, 'standardClass');
?>
Redeclared Static Variable
[Since 2.5.3] - [ -P Variables/RedeclaredStaticVariable ] - [ Online docs ]
Static variables shall be declared only once. It is forbidden in PHP 8.3 and later.
<?php
function foo() {
static $a;
static $a;
}
?>
Static Variable Can Default To Arbitrary Expression
[Since 2.5.3] - [ -P Php/StaticVariableDefaultCanBeAnyExpression ] - [ Online docs ]
Static variables can hold any type of PHP expression. Indeed, those are variables, so their value can be build from other variables, and even functioncalls.
This feature was introduced in PHP 8.3.
<?php
function foo($init) {
static $variable = foo($a);
return $variable++;
}
?>
Inherited Class Constant Visibility
[Since 2.5.3] - [ -P Interfaces/InheritedClassConstantVisibility ] - [ Online docs ]
Visibility of class constant must be public, even when overwritten.
<?php
interface i {
public const I = 1;
public const J = 2;
}
class x implements i {
// This should not be possible
private const I = 10;
public const J = 20;
}
?>
Final Traits Are Final
[Since 2.5.3] - [ -P Traits/FinalTraitsAreFinal ] - [ Online docs ]
A final method in a trait is also final when in its importing class. This means that the importing class may redefine it, but not the children.
<?php
trait t {
final function FFinal() {}
final function FNotFinalInClass() {}
function FNotFinal() {} // This is a normal method
}
class x {
use t;
function FNotFinalInClass() {}
}
class y extends x {
function FFinal() {} // This is KO, as it is final in the trait
function FNotFinalInClass() {} // This is OK, the class as priority
function FNotFinal() {}
}
?>
Typed Class Constants Usage
[Since 2.6.0] - [ -P Classes/TypedClassConstants ] - [ Online docs ]
Class constants may be