PHP 7.4 UPGRADE NOTES 1. Backward Incompatible Changes 2. New Features 3. Changes in SAPI modules 4. Deprecated Functionality 5. Changed Functions 6. New Functions 7. New Classes and Interfaces 8. Removed Extensions and SAPIs 9. Other Changes to Extensions 10. New Global Constants 11. Changes to INI File Handling 12. Windows Support 13. Migration to pkg-config 14. Other Changes 15. Performance Improvements ======================================== 1. Backward Incompatible Changes ======================================== - Core: . get_declared_classes() no longer returns anonymous classes that haven't been instantiated yet. . "fn" is now a reserved keyword. In particular it can no longer be used as a function or class name. It can still be used as a method or class constant name. . Passing the result of a (non-reference) list() assignment by reference is consistently disallowed now. Previously this worked if the right hand side was a simple (CV) variable and did not occur as part of the list(). - BCMath: . BCMath functions will now warn if a non well-formed number is passed, such as "32foo". The argument will be interpreted as zero (as before). - Curl: . Attempting to serialize a CURLFile class will now generate an exception. Previously the exception was only thrown on unserialization. . Using CURLPIPE_HTTP1 is deprecated, and is no longer supported as of cURL 7.62.0. . The $version parameter of curl_version() is deprecated. If any value not equal to the default CURLVERSION_NOW is passed, a warning is raised and the parameter is ignored. - Date: . Calling var_dump() or similar on a DateTime(Immutable) instance will no longer leave behind accessible properties on the object. . Comparison of DateInterval objects (using ==, < and so on) will now generate a warning and always return false. Previously all DateInterval objects were considered equal, unless they had properties. - Intl: . The default parameter value of idn_to_ascii() and idn_to_utf8() is now INTL_IDNA_VARIANT_UTS46 instead of the deprecated INTL_IDNA_VARIANT_2003. - MySQLi: . The embedded server functionality has been removed. It was broken since at least PHP 7.0. - Openssl: . The openssl_random_pseudo_bytes() function will now throw an exception in error situations, similar to random_bytes(). In particular, an Error is thrown if the number of requested bytes is smaller *or equal* than zero, and an Exception is thrown is sufficient randomness cannot be gathered. The $crypto_strong output argument is guaranteed to always be true if the function does not throw, so explicitly checking it is not necessary. RFC: http://php.net/manual/de/function.openssl-random-pseudo-bytes.php - PCRE: . When PREG_UNMATCHED_AS_NULL mode is used, trailing unmatched capturing groups will now also be set to null (or [null, -1] if offset capture is enabled). This means that the size of the $matches will always be the same. - PEAR: . 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. - PDO: . Attempting to serialize a PDO or PDOStatement instance will now generate an Exception rather than a PDOException, consistent with other internal classes which do not support serialization. - Reflection: . Reflection objects will now generate an exception if an attempt is made to serialize them. Serialization for reflection objects was never supported and resulted in corrupted reflection objects. It has been explicitly prohibited now. - SPL: . Calling get_object_vars() on an ArrayObject instance will now always return the properties of the ArrayObject itself (or a subclass). Previously it returned the values of the wrapped array/object unless the STD_PROP_LIST flag was specified. Other affected operations are: * ReflectionObject::getProperties() * reset(), current(), etc. Use Iterator methods instead. * Potentially others working on object properties as a list. (array) casts are *not* affected. They will continue to return either the wrapped array, or the ArrayObject properties, depending on whether the STD_PROP_LIST flag is used. . SplPriorityQueue::setExtractFlags() will throw an exception if zero is passed. Previously this would generate a recoverable fatal error on the next extraction operation. . ArrayObject, ArrayIterator, SplDoublyLinkedList and SplObjectStorage now support the __serialize() + __unserialize() mechanism in addition to the Serializable interface. This means that serialization payloads created on older PHP versions can still be unserialized, but new payloads created by PHP 7.4 will not be understood by older versions. - Standard: . The "o" serialization format has been removed. As it is never produced by PHP, this may only break unserialization of manually crafted strings. . Password hashing algorithm identifiers are now nullable strings rather than integers. * PASSWORD_DEFAULT was int 1; now is null * PASSWORD_BCRYPT was int 1; now is string '2y' * PASSWORD_ARGON2I was int 2; now is string 'argon2i' * PASSWORD_ARGON2ID was int 3; now is string 'argon2id' Applications correctly using the constants PASSWORD_DEFAULT, PASSWORD_BCRYPT, PASSWORD_ARGON2I, and PASSWORD_ARGON2ID will continue to function correctly. ======================================== 2. New Features ======================================== - Core: . Added support for typed properties. For example: class User { public int $id; public string $name; } This will enforce that $user->id can only be assigned integer and $user->name can only be assigned strings. For more information see the RFC: https://wiki.php.net/rfc/typed_properties_v2 . Added support for arrow functions with implicit by-value scope binding. For example: $factor = 10; $nums = array_map(fn($num) => $num * $factor, $nums); RFC: https://wiki.php.net/rfc/arrow_functions_v2 . Added support for limited return type covariance and argument type contravariance. The following code will now work: class A {} class B extends A {} class Producer { public function method(): A {} } class ChildProducer extends Producer { public function method(): B {} } This feature is currently restricted to non-cyclic type references only. RFC: https://wiki.php.net/rfc/covariant-returns-and-contravariant-parameters . Added support for coalesce assign (??=) operator. For example: $array['key'] ??= computeDefault(); // is roughly equivalent to if (!isset($array['key'])) { $array['key'] = computeDefault(); } RFC: https://wiki.php.net/rfc/null_coalesce_equal_operator . Added support for unpacking inside arrays. For example: $arr1 = [3, 4]; $arr2 = [1, 2, ...$arr1, 5]; // $arr2 == [1, 2, 3, 4, 5] RFC: https://wiki.php.net/rfc/spread_operator_for_array . Support for WeakReferences has been added. RFC: https://wiki.php.net/rfc/weakrefs . The eval() can be now disabled via disable_functions INI directive. - CURL: . CURLFile now supports stream wrappers in addition to plain file names, if the extension has been built against libcurl >= 7.56.0. The streams may need to be seekable. - Filter: . The FILTER_VALIDATE_FLOAT filter now supports the min_range and max_range options, with the same semantics as FILTER_VALIDATE_INT. - FFI: . A new extension which provides a simple way to call native functions, access native variables and create/access data structures defined in C libraries. RFC: https://wiki.php.net/rfc/ffi - GD: . Added the "scatter" image filter (IMG_FILTER_SCATTER) to apply a scatter filter to images. This filter has the following prototype: imagefilter($im, IMG_FILTER_SCATTER, int $sub, int $plus, array $colors = []); The $colors array can be populated with a set of indexed colors where to apply the scatter pixel shifting on. Note, the result of this filter is always random. - Hash: . Added "crc32c" hash using Castagnoli's polynomial. This crc32 variant is used by storage systems, such as iSCSI, SCTP, Btrfs and ext4. - Mbstring: . Added mb_str_split() function, which provide the same functionality as str_split(), but operating on code points rather than bytes. RFC: https://wiki.php.net/rfc/mb_str_split - OPcache: . Support for preloading code has been added. RFC: https://wiki.php.net/rfc/preload - PCRE: . The preg_replace_callback() and preg_replace_callback_array() functions now accept an additional $flags argument, with support for the PREG_OFFSET_CAPTURE and PREG_UNMATCHED_AS_NULL flags. This influences the format of the matches array passed to to the callback function. - PDO_OCI: . PDOStatement::getColumnMeta() is now available - PDO_SQLite: . PDOStatement::getAttribute(PDO::SQLITE_ATTR_READONLY_STATEMENT) allows to check whether this statement is read-only, i.e. whether it doesn't modify the database. - Standard: . strip_tags() now also accepts an array of allowed tags: Instead of strip_tags($str, '

') you can now write strip_tags($str, ['a', 'p']). . A new mechanism for custom object serialization has been added, which uses two new magic methods: // Returns array containing all the necessary state of the object. public function __serialize(): array; // Restores the object state from the given data array. public function __unserialize(array $data): void; The new serialization mechanism supersedes the Serializable interface, which will be deprecated in the future. RFC: https://wiki.php.net/rfc/custom_object_serialization . array_merge() and array_merge_recursive() may now be called without any arguments, in which case they will return an empty array. This is useful in conjunction with the spread operator, e.g. array_merge(...$arrays). ======================================== 3. Changes in SAPI modules ======================================== ======================================== 4. Deprecated Functionality ======================================== - Core: . Nesting ternary operators without explicit parentheses is deprecated: // Code like $a ? $b : $c ? $d : $e // should be replaced by (current interpretation) ($a ? $b : $c) ? $d : $e // or (likely intended interpretation) $a ? $b : ($c ? $d : $e) RFC: https://wiki.php.net/rfc/ternary_associativity . Unbinding $this of a non-static method through a combination of ReflectionMethod::getClosure() and closure rebinding is deprecated. Doing so is equivalent to calling a non-static method statically, which has been deprecated since PHP 7.0. . Using "parent" inside a class without parent is deprecated, and will throw a compile-time error in the future. Currently an error will only be generated if/when the parent is accessed at run-time. - COM: . Importing type libraries with case-insensitive constant registering has been deprecated. - Mbstring: . Passing a non-string pattern to mb_ereg_replace() is deprecated. Currently non-string patterns are interpreted as ASCII codepoints. In PHP 8 the pattern will be interpreted as a string instead. - LDAP: . ldap_control_paged_result_response and ldap_control_paged_result are deprecated. Pagination controls can be sent along with ldap_search instead. ======================================== 5. Changed Functions ======================================== - SPL: . SplFileObject::fputcsv(), ::fgetcsv() and ::setCsvControl() now accept an empty string as $escape argument, which disables the proprietary PHP escaping mechanism. SplFileObject::getCsvControl() now may also return an empty string for the third array element, accordingly. - Standard: . fputcsv() and fgetcsv() 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). . proc_open() on Windows can be passed a "create_process_group" option. It is required, if the child process is supposed to handle CTRL events. . password_hash() now accepts nullable string and int as $algo argument. . password_needs_rehash() now accepts nullable string and int as $algo argument. ======================================== 6. New Functions ======================================== - OpenSSL: . Added openssl_x509_verify(mixed cert, mixed key) function that verifies the signature of the certificate using a public key. A wrapper around the OpenSSL's X509_verify() function. See . - Pcntl: . Added bool pcntl_unshare(int flags) function which allows to dissociate parts of the process execution context which are currently being shared with other processes. Explicitly, it allows you to unshare the mount, IPC, UTS, network, PID, user and cgroup namespaces. - SQLite3: . Added SQLite3Stmt::getSQL() to retrieve the SQL of the statement. If TRUE is passed as parameter, query parameters will be replaced in the return value by their currently bound value, if libsqlite ≥ 3.14 is used. - Standard . bool sapi_windows_set_ctrl_handler(callable handler, [, bool add = true]) - set or remove a handler function upon receiving a CTRL event. The handler function is expected have a signature "function handler(int $event)". . bool sapi_windows_generate_ctrl_event(int type, int pid) - send a CTRL event to another process. . array password_algos() - return a complete list of all registered password hashing algorithms. For more details see the RFC: https://wiki.php.net/rfc/password_registry ======================================== 7. New Classes and Interfaces ======================================== - Reflection: . A new ReflectionReference class has been added, which allows detecting references and comparing them for identity. For more details see the RFC: https://wiki.php.net/rfc/reference_reflection ======================================== 8. Removed Extensions and SAPIs ======================================== - Interbase: . The interbase extension has been moved to PECL. Access to an InterBase and/or FireBird based database is still available with the PDO_Firebird extension. For more details see the RFC: https://wiki.php.net/rfc/deprecate-and-remove-ext-interbase - WDDX: . The WDDX extension has been deprecated and moved to PECL. RFC: https://wiki.php.net/rfc/deprecate-and-remove-ext-wddx ======================================== 9. Other Changes to Extensions ======================================== - GD: . 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 * Threshold-cropping now uses the algorithm of system libgd . 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. - Filter: . The filter extension no longer exposes --with-pcre-dir for Unix builds and can now reliably be built as shared when using ./configure once more. - Hash: . The hash extension cannot be disabled anymore and is always an integral part of any PHP build, similar to the date extension. - Intl: . The Intl extension now requires at least ICU 50.1. - Libxml: . All libxml based extensions now require libxml 2.7.6 or newer. - Mbstring: . 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. - OPcache: . The --disable-opcache-file|--enable-opcache-file configure options have been removed in favor of the opcache.file_cache INI directive. - Reflection: . Numeric value of class, property, function and constant modifiers was changed. Don't filter methods and properties through ReflectionClass::getMethods() and ReflectionClass::getProperties(), or test results of Reflection...::getModifiers(), using hard-coded numeric values. Use corresponding constants instead (e.g. ReflectionMethod::IS_PUBLIC). - SQLite3: . 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. . (Un)serialization 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. - Zip: . The bundled libzip library has been removed. A system libzip >= 0.11 is now necessary to build the extension. ======================================== 10. New Global Constants ======================================== - Mbstring: . MB_ONIGURUMA_VERSION specifies the version of the oniguruma library against which mbregex has been built. - Socket: . Added FreeBSD-specific socket options: . SO_LABEL . SO_PEERLABEL . SO_LISTENQLIMIT . SO_LISTENQLEN . SO_USER_COOKIE - Standard: . PHP_WINDOWS_EVENT_CTRL_C . PHP_WINDOWS_EVENT_CTRL_BREAK - Tidy: . TIDY_TAG_ARTICLE . TIDY_TAG_ASIDE . TIDY_TAG_AUDIO . TIDY_TAG_BDI . TIDY_TAG_CANVAS . TIDY_TAG_COMMAND . TIDY_TAG_DATALIST . TIDY_TAG_DETAILS . TIDY_TAG_DIALOG . TIDY_TAG_FIGCAPTION . TIDY_TAG_FIGURE . TIDY_TAG_FOOTER . TIDY_TAG_HEADER . TIDY_TAG_HGROUP . TIDY_TAG_MAIN . TIDY_TAG_MARK . TIDY_TAG_MENUITEM . TIDY_TAG_METER . TIDY_TAG_NAV . TIDY_TAG_OUTPUT . TIDY_TAG_PROGRESS . TIDY_TAG_SECTION . TIDY_TAG_SOURCE . TIDY_TAG_SUMMARY . TIDY_TAG_TEMPLATE . TIDY_TAG_TIME . TIDY_TAG_TRACK . TIDY_TAG_VIDEO ======================================== 11. Changes to INI File Handling ======================================== ======================================== 12. Windows Support ======================================== - stat: . The stat implementation has been refactored. - An inode number is delivered and is based on the NTFS file index. - The device number is now based on the volume serial number. Note, that both values derived from the system and provided as is on 64-bit systems. On 32-bit system, these values might overflow the 32-bit integer in PHP, so they're a fake. - CTRL+C and CTRL+BREAK on console can be caught by setting a handler function with sapi_windows_set_ctrl_handler(). ======================================== 13. Migration to pkg-config ======================================== 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: - Curl: . --with-curl no longer accepts a directory. - Enchant: . --with-enchant no longer accepts a directory. - FPM: . --with-fpm-systemd now uses only pkg-config for libsystem checks. The libsystemd minimum required version is 209. - GD: . --with-gd becomes --enable-gd (whether to enable the extension at all) and --with-external-gd (to opt into using an external libgd, rather than the bundled one). . --with-png-dir has been removed. libpng is required. . --with-zlib-dir has been removed. zlib is required. . --with-freetype-dir becomes --with-freetype. . --with-jpeg-dir becomes --with-jpeg. . --with-webp-dir becomes --with-webp. . --with-xpm-dir becomes --with-xpm. - IMAP: . --with-kerberos no longer accepts a directory. - Intl: . --with-icu-dir has been removed. If --enable-intl is passed, then libicu is always required. - Libxml: . --with-libxml-dir has been removed. . --enable-libxml becomes --with-libxml. . --with-libexpat-dir has been renamed to --with-expat and no longer accepts a directory. - LiteSpeed: . --with-litespeed becomes --enable-litespeed. - Mbstring: . --with-onig has been removed. Unless --disable-mbregex has been passed, libonig is required. - ODBC: . --with-iodbc no longer accepts a directory. . --with-unixODBC no longer accepts a directory. - OpenSSL: . --with-openssl no longer accepts a directory. . --with-kerberos no longer accepts a directory. - PCRE: . --with-pcre-regex has been removed. Instead --with-external-pcre is provided to opt into using an external PCRE library, rather than the bundled one. - PDO_SQLite: . --with-pdo-sqlite no longer accepts a directory. - Readline: . --with-libedit no longer accepts a directory. - Sodium: . --with-sodium no longer accepts a directory. - SQLite3: . --with-sqlite3 no longer accepts a directory. - Zip: . --with-libzip has been removed. . --enable-zip becomes --with-zip. ======================================== 14. Other Changes ======================================== ======================================== 15. Performance Improvements ======================================== - Core: . 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. - PCRE: . 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.