PHP 7.0 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. Other Changes ======================================== 1. Backward Incompatible Changes ======================================== Language changes ================ Changes to variable handling ---------------------------- * Indirect variable, property and method references are now interpreted with left-to-right semantics. Some examples: $$foo['bar']['baz'] // interpreted as ($$foo)['bar']['baz'] $foo->$bar['baz'] // interpreted as ($foo->$bar)['baz'] $foo->$bar['baz']() // interpreted as ($foo->$bar)['baz']() Foo::$bar['baz']() // interpreted as (Foo::$bar)['baz']() To restore the previous behavior add explicit curly braces: ${$foo['bar']['baz']} $foo->{$bar['baz']} $foo->{$bar['baz']}() Foo::{$bar['baz']}() * The global keyword now only accepts simple variables. Instead of global $$foo->bar; it is now required to write the following: global ${$foo->bar}; * Parentheses around variables or function calls no longer have any influence on behavior. For example the following code, where the result of a function call is passed to a by-reference function function getArray() { return [1, 2, 3]; } $last = array_pop(getArray()); // Strict Standards: Only variables should be passed by reference $last = array_pop((getArray())); // Strict Standards: Only variables should be passed by reference will now throw a strict standards error regardless of whether parentheses are used. Previously no notice was generated in the second case. * Array elements or object properties that are automatically created during by-reference assignments will now result in a different order. For example $array = []; $array["a"] =& $array["b"]; $array["b"] = 1; var_dump($array); now results in the array ["a" => 1, "b" => 1], while previously the result was ["b" => 1, "a" => 1]; Relevant RFCs: * https://wiki.php.net/rfc/uniform_variable_syntax * https://wiki.php.net/rfc/abstract_syntax_tree Changes to list() ----------------- * list() will no longer assign variables in reverse order. For example list($array[], $array[], $array[]) = [1, 2, 3]; var_dump($array); will now result in $array == [1, 2, 3] rather than [3, 2, 1]. Note that only the **order** of the assignments changed, but the assigned values stay the same. E.g. a normal usage like list($a, $b, $c) = [1, 2, 3]; // $a = 1; $b = 2; $c = 3; will retain its current behavior. * Empty list() assignments are no longer allowed. As such all of the following are invalid: list() = $a; list(,,) = $a; list($x, list(), $y) = $a; * list() no longer supports unpacking strings (while previously this was only supported in some cases). The code $string = "xy"; list($x, $y) = $string; will now result in $x == null and $y == null (without notices) instead of $x == "x" and $y == "y". Furthermore list() is now always guaranteed to work with objects implementing ArrayAccess, e.g. list($a, $b) = (object) new ArrayObject([0, 1]); will now result in $a == 0 and $b == 1. Previously both $a and $b were null. Relevant RFCs: * https://wiki.php.net/rfc/abstract_syntax_tree#changes_to_list * https://wiki.php.net/rfc/fix_list_behavior_inconsistency Changes to foreach ------------------ * Iteration with foreach() no longer has any effect on the internal array pointer, which can be accessed through the current()/next()/etc family of functions. For example $array = [0, 1, 2]; foreach ($array as &$val) { var_dump(current($array)); } will now print the value int(0) three times. Previously the output was int(1), int(2) and bool(false). * When iterating arrays by-value, foreach will now always operate on a copy of the array, as such changes to the array during iteration will not influence iteration behavior. For example $array = [0, 1, 2]; $ref =& $array; // Necessary to trigger the old behavior foreach ($array as $val) { var_dump($val); unset($array[1]); } will now print all three elements (0 1 2), while previously the second element 1 was skipped (0 2). * When iterating arrays by-reference, modifications to the array will continue to influence the iteration. However PHP will now do a better job of maintaining a correct position in a number of cases. E.g. appending to an array during by-reference iteration $array = [0]; foreach ($array as &$val) { var_dump($val); $array[1] = 1; } will now iterate over the appended element as well. As such the output of this example will now be "int(0) int(1)", while previously it was only "int(0)". * Iteration of plain (non-Traversable) objects by-value or by-reference will behave like by-reference iteration of arrays. This matches the previous behavior apart from the more accurate position management mentioned in the previous point. * Iteration of Traversable objects remains unchanged. Relevant RFC: https://wiki.php.net/rfc/php7_foreach Changes to parameter handling ----------------------------- * It is no longer possible to define two function parameters with the same name. For example, the following method will trigger a compile-time error: public function foo($a, $b, $unused, $unused) { // ... } Code like this should be changed to use distinct parameter names, for example: public function foo($a, $b, $unused1, $unused2) { // ... } * The func_get_arg() and func_get_args() functions will no longer return the original value that was passed to a parameter and will instead provide the current value (which might have been modified). For example function foo($x) { $x++; var_dump(func_get_arg(0)); } foo(1); will now print "2" instead of "1". This code should be changed to either perform modifications only after calling func_get_arg(s) function foo($x) { var_dump(func_get_arg(0)); $x++; } or avoid modifying the parameters altogether: function foo($x) { $newX = $x + 1; var_dump(func_get_arg(0)); } * Similarly exception backtraces will no longer display the original value that was passed to a function and show the modified value instead. For example function foo($x) { $x = 42; throw new Exception; } foo("string"); will now result in the stack trace Stack trace: #0 file.php(4): foo(42) #1 {main} while previously it was: Stack trace: #0 file.php(4): foo('string') #1 {main} While this should not impact runtime behavior of your code, it is worthwhile to be aware of this difference for debugging purposes. The same limitation also applies to debug_backtrace() and other functions inspecting function arguments. Relevant RFC: https://wiki.php.net/phpng Changes to integer handling --------------------------- * Invalid octal literals (containing digits larger than 7) now produce compile errors. For example, the following is no longer valid: $i = 0781; // 8 is not a valid octal digit! Previously the invalid digits (and any following valid digits) were simply ignored. As such $i previously held the value 7, because the last two digits were silently discarded. * Bitwise shifts by negative numbers will now throw an ArithmeticError: var_dump(1 >> -1); // ArithmeticError: Bit shift by negative number * Left bitwise shifts by a number of bits beyond the bit width of an integer will always result in 0: var_dump(1 << 64); // int(0) Previously the behavior of this code was dependent on the used CPU architecture. For example on x86 (including x86-64) the result was int(1), because the shift operand was wrapped. * Similarly right bitwise shifts by a number of bits beyond the bit width of an integer will always result in 0 or -1 (depending on sign): var_dump(1 >> 64); // int(0) var_dump(-1 >> 64); // int(-1) Relevant RFC: https://wiki.php.net/rfc/integer_semantics Changes to string handling -------------------------- * Strings that contain hexadecimal numbers are no longer considered to be numeric and don't receive special treatment anymore. Some examples of the new behavior: var_dump("0x123" == "291"); // bool(false) (previously true) var_dump(is_numeric("0x123")); // bool(false) (previously true) var_dump("0xe" + "0x1"); // int(0) (previously 16) var_dump(substr("foo", "0x1")); // string(3) "foo" (previously "oo") // Notice: A non well formed numeric value encountered filter_var() can be used to check if a string contains a hexadecimal number or convert such a string into an integer: $str = "0xffff"; $int = filter_var($str, FILTER_VALIDATE_INT, FILTER_FLAG_ALLOW_HEX); if (false === $int) { throw new Exception("Invalid integer!"); } var_dump($int); // int(65535) * Due to the addition of the Unicode Codepoint Escape Syntax for double-quoted strings and heredocs, "\u{" followed by an invalid sequence will now result in an error: $str = "\u{xyz}"; // Fatal error: Invalid UTF-8 codepoint escape sequence To avoid this the leading backslash should be escaped: $str = "\\u{xyz}"; // Works fine However, "\u" without a following { is unaffected. As such the following code won't error and will work the same as before: $str = "\u202e"; // Works fine Relevant RFCs: * https://wiki.php.net/rfc/remove_hex_support_in_numeric_strings * https://wiki.php.net/rfc/unicode_escape Changes to error handling ------------------------- * There are now two exception classes: Exception and Error. Both classes implement a new interface Throwable. Type hints in exception handling code may need to be changed to account for this. * Some fatal errors and recoverable fatal errors now throw an Error instead. As Error is a separate class from Exception, these exceptions will not be caught by existing try/catch blocks. For the recoverable fatal errors which have been converted into an exception, it is no longer possible to silently ignore the error from an error handler. In particular, it is no longer possible to ignore type hint failures. * Parser errors now generate a ParseError that extends Error. Error handling for eval()s on potentially invalid code should be changed to catch ParseError in addition to the previous return value / error_get_last() based handling. * Constructors of internal classes will now always throw an exception on failure. Previously some constructors returned NULL or an unusable object. * The error level of some E_STRICT notices has been changed. Relevant RFCs: * https://wiki.php.net/rfc/engine_exceptions_for_php7 * https://wiki.php.net/rfc/throwable-interface * https://wiki.php.net/rfc/internal_constructor_behaviour * https://wiki.php.net/rfc/reclassify_e_strict Other language changes ---------------------- * Removed support for static calls to non-static methods from an incompatible $this context. In this case $this will not be defined, but the call will be allowed with a deprecation notice. An example: class A { public function test() { var_dump($this); } } // Note: Does NOT extend A class B { public function callNonStaticMethodOfA() { A::test(); } } (new B)->callNonStaticMethodOfA(); // Deprecated: Non-static method A::test() should not be called statically // Notice: Undefined variable $this NULL Note that this only applies to calls from an incompatible context. If class B extended from A the call would be allowed without any notices. * It is no longer possible to use the following class, interface and trait names (case-insensitive): bool int float string null false true This applies to class/interface/trait declarations, class_alias() and use statements. Furthermore the following class, interface and trait names are now reserved for future use, but do not yet throw an error when used: resource object mixed numeric * The yield language construct no longer requires parentheses when used in an expression context. It is now a right-associative operator with precedence between the "print" and "=>" operators. This can result in different behavior in some cases, for example: echo yield -1; // Was previously interpreted as echo (yield) - 1; // And is now interpreted as echo yield (-1); yield $foo or die; // Was previously interpreted as yield ($foo or die); // And is now interpreted as (yield $foo) or die; Such cases can always be resolved by adding additional parentheses. . Removed ASP (<%) and script (<script language=php>) tags. (RFC: https://wiki.php.net/rfc/remove_alternative_php_tags) . Removed support for assigning the result of new by reference. . Removed support for scoped calls to non-static methods from an incompatible $this context. See details in https://wiki.php.net/rfc/incompat_ctx. . Removed support for #-style comments in ini files. Use ;-style comments instead. . $HTTP_RAW_POST_DATA is no longer available. Use the php://input stream instead. Standard library changes ======================== . substr() now returns an empty string instead of FALSE when the truncation happens on boundaries. . call_user_method() and call_user_method_array() no longer exists. . ob_start() no longer issues an E_ERROR, but instead an E_RECOVERABLE_ERROR in case an output buffer is created in an output buffer handler. . The internal sorting algorithm has been improved, what may result in different sort order of elements that compare as equal. . Removed dl() function on fpm-fcgi. . setcookie() with an empty cookie name now issues a WARNING and doesn't send an empty set-cookie header line anymore. Other ===== - Curl: . Removed support for disabling the CURLOPT_SAFE_UPLOAD option. All curl file uploads must use the curl_file / CURLFile APIs. - Date: . Removed $is_dst parameter from mktime() and gmmktime(). - DBA . dba_delete() now returns false if the key was not found for the inifile handler, too. - GMP . Requires libgmp version 4.2 or newer now. . gmp_setbit() and gmp_clrbit() now return FALSE for negative indices, making them consistent with other GMP functions. - Intl: . Removed deprecated aliases datefmt_set_timezone_id() and IntlDateFormatter::setTimeZoneID(). Use datefmt_set_timezone() and IntlDateFormatter::setTimeZone() instead. - libxml: . Added LIBXML_BIGLINES parser option. It's available starting with libxml 2.9.0 and adds suppport for line numbers >16-bit in the error reporting. - Mcrypt . Removed deprecated mcrypt_generic_end() alias in favor of mcrypt_generic_deinit(). . Removed deprecated mcrypt_ecb(), mcrypt_cbc(), mcrypt_cfb() and mcrypt_ofb() functions in favor of mcrypt_encrypt() and mcrypt_decrypt() with an MCRYPT_MODE_* flag. - Session . session_start() accepts all INI settings as array. e.g. ['cache_limiter'=>'private'] sets session.cache_limiter=private. It also supports 'read_and_close' which closes session data immediately after read data. . Save handler accepts validate_sid(), update_timestamp() which validates session ID existence, updates timestamp of session data. Compatibility of old user defined save handler is retained. . SessionUpdateTimestampHandlerInterface is added. validateSid(), updateTimestamp() is defined in the interface. . session.lazy_write(default=On) INI setting enables only write session data when session data is updated. - Opcache . Removed opcache.load_comments configuration directive. Now doc comments loading costs nothing and always enabled. - OpenSSL: . Removed the "rsa_key_size" SSL context option in favor of automatically setting the appropriate size given the negotiated crypto algorithm. . Removed "CN_match" and "SNI_server_name" SSL context options. Use automatic detection or the "peer_name" option instead. - PCRE: . Removed support for /e (PREG_REPLACE_EVAL) modifier. Use preg_replace_callback() instead. - PDO_pgsql: . Removed PGSQL_ATTR_DISABLE_NATIVE_PREPARED_STATEMENT attribute in favor of ATTR_EMULATE_PREPARES. - Standard: . Removed string category support in setlocale(). Use the LC_* constants instead. . Removed set_magic_quotes_runtime() and its alias magic_quotes_runtime(). - JSON: . Rejected RFC 7159 incompatible number formats in json_decode string - top level (07, 0xff, .1, -.1) and all levels ([1.], [1.e1]) . Calling json_decode with 1st argument equal to empty PHP string or value that after casting to string is empty string (NULL, FALSE) results in JSON syntax error. - Stream: . Removed set_socket_blocking() in favor of its alias stream_set_blocking(). - XSL: . Removed xsl.security_prefs ini option. Use XsltProcessor::setSecurityPrefs() instead. ======================================== 2. New Features ======================================== - Core . Added group use declarations. (RFC: https://wiki.php.net/rfc/group_use_declarations) . Added null coalesce operator (??). (RFC: https://wiki.php.net/rfc/isset_ternary) . Support for strings with length >= 2^31 bytes in 64 bit builds. . Closure::call() method added (works only with userland classes). . Added \u{xxxxxx} Unicode Codepoint Escape Syntax for double-quoted strings and heredocs. . define() now supports arrays as constant values, fixing an oversight where define() did not support arrays yet const syntax did. . Added the comparison operator (<=>), aka the spaceship operator. (RFC: https://wiki.php.net/rfc/combined-comparison-operator) . Added the yield from operator for delegating Generators like coroutines. (RFC: https://wiki.php.net/rfc/generator-delegation) . Reserved keywords can now be used in various new contexts. (RFC: https://wiki.php.net/rfc/context_sensitive_lexer) . Added support for scalar type declarations and strict mode using declare(strict_types=1) (RFC: https://wiki.php.net/rfc/scalar_type_hints_v5) . Added support for cryptographically secure user land RNG (RFC: https://wiki.php.net/rfc/easy_userland_csprng) - Opcache . Added second level file based opcode cache. It may be enabled by setting opcache.file_cache=<DIR> configuration directive in php.ini. The second level cache may improve performance when SHM is full, at server restart or SHM reset. In addition, it's possibe to use file cache without SHM at all, using opcache.file_cache_only=1 (this may be useful for sharing hosting), and disable file cache consistency check, to speedup loading at the cost of safety, using opcache.file_cache_consistency_checks=0. . Added ability to move PHP code pages (PHP TEXT segment) into HUGE pages. It's possible to enable/disable this feature in php.ini through opcache.huge_code_pages=0/1. OS should be configured to provide huge pages. . Added Windows only opcache.file_cache_fallback=1 ini option, which implies the implemented fallback mechanism. When OPcache was not able to reattach the shared memory segment to the desired address and opcache.file_cache is on, opcache.file_cache_only=1 will be automatically enforced. - OpenSSL . Added "alpn_protocols" SSL context option allowing encrypted client/server streams to negotiate alternative protocols using the ALPN TLS extension when built against OpenSSL 1.0.2 or newer. Negotiated protocol information is accessible through stream_get_meta_data() output. - Reflection . Added a ReflectionGenerator class (yield from Traces, current file/line, etc.) . Added a ReflectionType class to better support the new return type and scalar type declarations features. The new ReflectionParameter::getType() and ReflectionFunctionAbstract::getReturnType() methods both return an instance of ReflectionType. - Stream: . New Windows only stream context options was added to allow blocking reads on pipes. To enable it, pass array("pipe" => array("blocking" => true)) when creating the stream context. Be aware, that this option can under circumstances cause dead locks on the pipe buffer. However it can be useful in several CLI use case scenarios. ======================================== 3. Changes in SAPI modules ======================================== - FPM . Fixed bug #65933 (Cannot specify config lines longer than 1024 bytes). . Listen = port now listen on all addresses (IPv6 and IPv4-mapped). ======================================== 4. Deprecated Functionality ======================================== - Core . PHP 4 style constructors, where the constructor name is the same as the class name, are now deprecated. . Static calls to non-static methods are now deprecated. - OpenSSL . The "capture_session_meta" SSL context option is now deprecated. Meta data concerning active crypto on a stream resource is now accessible through the return result from stream_get_meta_data(). ======================================== 5. Changed Functions ======================================== - unserialize(): . Added second parameter for unserialize function (RFC: https://wiki.php.net/rfc/secure_unserialize) allowing to specify acceptable classes: unserialize($foo, ["allowed_classes" => ["MyClass", "MyClass2"]]); - proc_open(): . The maximum number of pipes used by proc_open() was previously limited by hardcoded value of 16. This limit is now removed and the number of pipes is effectively limited by the amount of memory available to PHP. . New Windows only configuration option "blocking_pipes" can be used to force blocking reads on child process pipes. This covers several edge cases in CLI usage however can lead to dead locks. Also, this correlates with the new stream context options for pipes. - array_column(): The function now supports an array of objects as well as two-dimensional arrays. Only public properties are considered, and objects that make use of __get() for dynamic properties must also implement __isset(). - stream_context_create() It accepts now a Windows only configuration array("pipe" => array("blocking" => <boolean>)) which forces blocking reads on pipes. This option should be used carefully because due to the platform restrictions dead locks on pipe buffers are possible. - dirname() A new optional argument ($levels) allow to go up various times dirname(dirname($foo)) => dirname($foo, 2); - debug_zval_dump It prints now "int" instead of "long", and "float" instead of "double". ======================================== 6. New Functions ======================================== - GMP . Added gmp_random_seed(). - PCRE: . Added preg_replace_callback_array function (RFC: https://wiki.php.net/rfc/preg_replace_callback_array) - Standard . Added intdiv() function for integer division. . Added error_clear_last() function to reset error state. - Zip: . Added ZipArchive::setCompressionIndex() and ZipArchive::setCompressionName() for setting the compression method. - Zlib: . Added deflate_init(), deflate_add(), inflate_init(), inflate_add() functions allowing incremental/streaming compression/decompression. ======================================== 7. New Classes and Interfaces ======================================== - ReflectionGenerator - ReflectionType ======================================== 8. Removed Extensions and SAPIs ======================================== - sapi/aolserver - sapi/apache - sapi/apache_hooks - sapi/apache2filter - sapi/caudium - sapi/continuity - sapi/isapi - sapi/milter - sapi/nsapi - sapi/phttpd - sapi/pi3web - sapi/roxen - sapi/thttpd - sapi/tux - sapi/webjames - ext/mssql - ext/mysql - ext/sybase_ct - ext/ereg For more details see https://wiki.php.net/rfc/removal_of_dead_sapis_and_exts https://wiki.php.net/rfc/remove_deprecated_functionality_in_php7 NOTE: NSAPI was not voted in the RFC, however it was removed afterwards. It turned out, that the corresponding SDK isn't available anymore. ======================================== 9. Other Changes to Extensions ======================================== - Mhash Mhash is not an extension anymore, use function_exists("mhash") to check whether it is avaliable. - GD The bundled libgd requires libwebp instead of libvpx for the WebP functionality. - Openssl minimum supported OpenSSL version series was raised to 0.9.8 ======================================== 10. New Global Constants ======================================== - Core . PHP_INT_MIN added. - PCRE . This error constant is added to signal errors due to stack size limitations when PCRE JIT support is enabled: . PREG_JIT_STACKLIMIT_ERROR - Zlib . These constants are added to control flush behavior with the new incremental deflate_add() and inflate_add() functions: . ZLIB_NO_FLUSH . ZLIB_PARTIAL_FLUSH . ZLIB_SYNC_FLUSH . ZLIB_FULL_FLUSH . ZLIB_BLOCK . ZLIB_FINISH - GD . T1Lib support removed, thus lifting the optional dependency on T1Lib, the following is therefore not available anymore: Functions: - imagepsbbox() - imagepsencodefont() - imagepsextendedfont() - imagepsfreefont() - imagepsloadfont() - imagepsslantfont() - imagepstext() Resources: - 'gd PS font' - 'gd PS encoding' ======================================== 11. Changes to INI File Handling ======================================== - Core . Removed asp_tags ini directive. Trying to enable it will result in a fatal error. . Removed always_populate_raw_post_data ini directive. ======================================== 12. Windows Support ======================================== - Core . Support for native 64 bit integers in 64 bit builds. . Support for large files in 64 bit builds. . Support for getrusage() - ftp . The ftp extension is always shipped shared . For SSL support, the dependency on the openssl extension was abolished. Instead it depends alone on the openssl library. If it's present at the compile time, ftp_ssl_connect() is enabled automatically. - imap . Static building of ext/imap is disabled - odbc . The odbc extension is always shipped shared ======================================== 13. Other Changes ======================================== - Core . Instead of being undefined and platform-dependent, NaN and Infinity will always be zero when cast to integer. . Calling a method on a non-object now raises a catchable error instead of a fatal error; see: https://wiki.php.net/rfc/catchable-call-to-member-of-non-object . Error messages for zend_parse_parameters, type hints and conversions now always say "integer" and "float" instead of "long" and "double". . Output buffering now continues to work for an aborted connection if ignore_user_abort is set to true. . Zend Extensions API was extended with zend_extension.op_array_persist_calc() and zend_extensions.op_array_persist() handlers. They allow to store (or reset) associated with op_array addition information in Opcache Shared Memory. . zend_internal_function.reserved[] array was introduced to allow association of aditional information with internal functions. In PHP-5 it was possible to use zend_function.op_array.reserved[] even for internal functions, but now we don't allocate extra space.