This version brings an important changes with the directive zend.exception_ignore_args set to On by default.
In all stack traces, the args key is now missing.
All php frameworks have to handle this to report errors & exceptions.
A specialized VM opcode for the array_key_exists() function has been added, which improves performance of this function if it can be statically resolved. In namespaced code, this may require writing \array_key_exists() or explicitly importing the function.
When preg_match() in UTF-8 mode ("u" modifier) is repeatedly called on the same string (but possibly different offsets), it will only be checked for UTF-8 validity once.
zend.exception_ignore_args is a new INI directive for including or excluding arguments from stack traces generated from exceptions.
opcache.preload_user is a new INI directive for specifying the user account under which preloading code is execute if it would otherwise be run as root (which is not allowed for security reasons).
A number of extensions have been migrated to exclusively use pkg-config for the detection of library dependencies. Generally, this means that instead of using --with-foo-dir=DIR or similar only --with-foo is used. Custom library paths can be specified either by adding additional directories to PKG_CONFIG_PATH or by explicitly specifying compilation options through FOO_CFLAGS and FOO_LIBS.
The following extensions and SAPIs are affected:
fputcsv(), fgetcsv(), SplFileObject::fputcsv(), SplFileObject::fgetcsv(), and SplFileObject::setCsvControl() now accept an empty string as $escape argument, which disables the proprietary PHP escaping mechanism.
The behavior of str_getcsv() has been adjusted accordingly (formerly, an empty string was identical to using the default).
SplFileObject::getCsvControl() now may also return an empty string for the third array element, accordingly.
The filter extension no longer exposes --with-pcre-dir for Unix builds and can now reliably be built as shared when using ./configure
The behavior of imagecropauto() in the bundled libgd has been synced with that of system libgd:
IMG_CROP_DEFAULT
is no longer falling
back to IMG_CROP_SIDES
The default $mode parameter of
imagecropauto() has been changed to
IMG_CROP_DEFAULT
; passing -1
is now deprecated.
imagescale() now supports aspect ratio preserving scaling to a fixed height by passing -1 as $new_width.
The hash extension cannot be disabled anymore and is always an integral part of any PHP build, similar to the date extension.
Support for nsldap and umich_ldap has been removed.
All libxml-based extensions now require libxml 2.7.6 or newer.
The oniguruma library is no longer bundled with PHP, instead libonig needs to be available on the system. Alternatively --disable-mbregex can be used to disable the mbregex component.
The --disable-opcache-file and --enable-opcache-file configure options have been removed in favor of the opcache.file_cache INI directive.
The password_hash() and functions now accept nullable string and integer for $algo argument.
Installation of PEAR (including PECL) is no longer enabled by default. It can be explicitly enabled using --with-pear . This option is deprecated and may be removed in the future.
The numeric values of the modifier constants (IS_ABSTRACT, IS_DEPRECATED, IS_EXPLICIT_ABSTRACT, IS_FINAL, IS_IMPLICIT_ABSTRACT, IS_PRIVATE, IS_PROTECTED, IS_PUBLIC, and IS_STATIC) on the ReflectionClass, ReflectionFunction, ReflectionMethod, ReflectionObject, and ReflectionProperty classes have changed.
SimpleXMLElement now implements Countable.
The bundled libsqlite has been removed. To build the SQLite3 extension a system libsqlite3 ≥ 3.7.4 is now required. To build the PDO_SQLite extension a system libsqlite3 ≥ 3.5.0 is now required.
Serialization and unserialization of SQLite3, SQLite3Stmt and SQLite3Result is now explicitly forbidden. Formerly, serialization of instances of these classes was possible, but unserialization yielded unusable objects.
The @param notation can now also be used to denote SQL query parameters.
The bundled libzip library has been removed. A system libzip >= 0.11 is now necessary to build the zip extension.
This version brings an important changes with the directive zend.exception_ignore_args set to On by default.
In all stack traces, the args key is now missing.
All php frameworks have to handle this to report errors & exceptions.
As of PHP 7.4, an exception thrown within the user-defined shutdown function can be caught by the user-defined exception handler.
<?php
set_error_handler(
function($level, $error, $file, $line){
if(0 === error_reporting()){
return false;
}
throw new ErrorException($error, -1, $level, $file, $line);
},
E_ALL
);
register_shutdown_function(function(){
$error = error_get_last();
if($error){
throw new ErrorException($error['message'], -1, $error['type'], $error['file'], $error['line']);
}
});
set_exception_handler(function($exception){
// ... more code ...
});
require 'NotExists.php';
Note for internals/extensions:
Many opcode values changed between PHP 7.3 and 7.4, so most documentation resources are outdated in that regard. You can look the definitions at Zend/zend_vm_opcodes.h in php-src. For example, ZEND_ECHO changes from 40 to 136.
While opcode changes happen in a lot of PHP versions, the change in 7.4 is quite significant.