-PHP 7.0 UPGRADE NOTES
+PHP 7.1 UPGRADE NOTES
1. Backward Incompatible Changes
2. New Features
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 calls form 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.
-
-- 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
========================================
-- parse_ini_file():
-- parse_ini_string():
- . Added scanner mode INI_SCANNER_TYPED to yield typed .ini values.
-- 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
========================================
-
========================================
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.
-
========================================
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.
-PHP 7.0 INTERNALS UPGRADE NOTES
+PHP 7.1 INTERNALS UPGRADE NOTES
0. Wiki Examples
1. Internal API changes
- e. New data types
- f. zend_parse_parameters() specs
- g. sprintf() formats
- h. HashTable API
- i. New portable macros for large file support
- j. New portable macros for integers
- k. get_class_entry object handler info
- l. get_class_name object handler info
- m. Other portable macros info
- n. ZEND_ENGINE_2 removal
- o. Updated final class modifier
- p. TSRM changes
- q. gc_collect_cycles() is now hookable
- r. PDO uses size_t for lengths
- s. Resource API changes
- t. Optimized strings concatenation.
- u. Streams changes
- v. Sort algorithm changes
2. Build system changes
a. Unix build system changes
1. Internal API changes
========================
- e. New data types
-
- String
-
- Besides the old way of accepting the strings with 's', the new 'S' ZPP spec
- was introduced. It expects an argument of the type zend_string *. String lengths
- in it are bound to the size_t datatype.
-
- Integer types
-
- Integers do no more depend on the firm 'long' type. Instead a platform
- dependent integer type is used, it is called zend_long. That datatype is
- defined dynamically to guarantee the consistent 64 bit support. The zval
- field representing user land integer it bound to zend_long.
-
- Signed integer is defined as zend_long, unsigned integer as zend_ulong
- inside Zend.
-
- Other datatypes
-
- zend_off_t - portable off_t analogue
- zend_stat_t - portable 'struct stat' analogue
-
- These datatypes are declared to be portable across platforms. Thus, direct
- usage of the functions like fseek, stat, etc. as well as direct usage of
- off_t and struct stat is strongly not recommended. Instead the portable
- macros should be used.
-
- zend_fseek - portable fseek equivalent
- zend_ftell - portable ftell equivalent
- zend_lseek - portable lseek equivalent
- zend_fstat - portable fstat equivalent
- zend_stat - portable stat equivalent
-
- f. zend_parse_parameters() specs
-
- The new spec 'S' introduced, which expects an argument of type zend_string *.
- The 'l' spec expects a parameter of the type zend_long, not long anymore.
- The 's' spec expects parameters of the type char * and size_t, no int anymore.
-
- g. sprintf() formats
-
- New printf modifier 'p' was implemented to platform independently output zend_long,
- zend_ulong and php_size_t datatypes. That modifier can be used with 'd', 'u', 'x' and 'o'
- printf format specs with spprintf, snprintf and the wrapping printf implementations.
- %pu is sufficient for both zend_ulong and php_size_t. the code using %p spec to output
- pointer address might need to be enclosed into #ifdef when it unlickily followed by 'd',
- 'u', 'x' or 'o'.
-
- The only exceptions are the snprintf and zend_sprintf functions yet, because in some cases
- they can use the implemenations available on the system, not the PHP one. With snprintf the
- macros ZEND_INT_FMT and ZEND_UINT_FMT should be used.
-
- h. HashTable API
-
- Datatype for array indexes was changed to zend_ulong, for string keys to zend_string *.
-
- i. New portable macros for large file support
-
- Function(s) Alias Comment
- stat, _stat64 zend_stat for use with zend_stat_t
- fstat, _fstat64 zend_fstat for use with zend_stat_t
- lseek, _lseeki64 zend_lseek for use with zend_off_t
- ftell, _ftelli64 zend_ftell for use with zend_off_t
- fseek, _fseeki64 zend_fseek for use with zend_off_t
-
- j. New portable macros for integers
-
- Function(s) Alias Comment
- snprintf with "%ld" or "%lld", _ltoa_s, _i64toa_s ZEND_LTOA for use with zend_long
- atol, atoll, _atoi64 ZEND_ATOL for use with zend_long
- strtol, strtoll, _strtoi64 ZEND_STRTOL for use with zend_long
- strtoul, strtoull, _strtoui64 ZEND_STRTOUL for use with zend_long
- abs, llabs, _abs64 ZEND_ABS for use with zend_long
- - ZEND_LONG_MAX replaces LONG_MAX where appropriate
- - ZEND_LONG_MIN replaces LONG_MIN where appropriate
- - ZEND_ULONG_MAX replaces ULONG_MAX where appropriate
- - SIZEOF_ZEND_LONG reworked SIZEOF_ZEND_LONG representing the size of zend_long datatype
- - ZEND_SIZE_MAX Max value of size_t
- - Z_L casts an integral constant to zend_long
- - Z_UL casts an integral constant to zend_ulong
-
- The macro ZEND_ENABLE_ZVAL_LONG64 reveals whether zval operates on 64 or 32 bit integer.
-
- k. The get_class_entry object handler is no longer available. Instead
- zend_object.ce is always used.
-
- l. The get_class_name object handler is now only used for displaying class
- names in debugging functions like var_dump(). It is no longer used in
- get_class(), get_parent_class() or similar.
-
- The handler is now obligatory, no longer accepts a `parent` argument and
- must return a non-NULL zend_string*, which will be released by the caller.
-
- m. Other portable macros info
-
- ZEND_SECURE_ZERO - zeroes chunk of memory
- ZEND_VALID_SOCKET - validates a php_socket_t variable
-
- ZEND_FASTCALL is defined to use __vectorcall convention on VS2013 and above
- ZEND_NORETURN is defined as __declspec(noreturn) on VS
-
- n. The ZEND_ENGINE_2 macro has been removed. A ZEND_ENGINE_3 macro has been added.
-
- o. Removed ZEND_ACC_FINAL_CLASS in favour of ZEND_ACC_FINAL, turning final class
- modifier now a different class entry flag. Update your extensions.
-
- p. TSRM changes
-
- The TSRM layer undergone significant changes. It is not necessary anymore to
- pass the tsrm_ls pointer explicitly. The TSRMLS_* macros should not be used
- in any new developments.
-
- The recommended way accessing globals in TS builds is by implementing it
- to use a local thread unique pointer to the corresponding data pool. These
- are the new macros that serve to achieve this goal:
-
- - ZEND_TSRMG - based on TSRMG and if static pointer for data pool access is
- implemented, will use it
- - ZEND_TSRMLS_CACHE_EXTERN - to be used in a header shared across multiple
- C/C++ files
- - ZEND_TSRMLS_CACHE_DEFINE - to be used in the main extension C/C++ file
- - ZEND_TSRMLS_CACHE_UPDATE - to be integrated at the top of the globals
- ctor or RINIT function
- - ZEND_ENABLE_STATIC_TSRMLS_CACHE - to be used in the config.[m4|w32] for
- enabling the globals access per thread unique pointer
- - TSRMLS_CACHE - expands to the variable name which links to the thread
- unique data pool
-
- Note that usually it will work without implementing the globals access per
- a thread unique pointer, however it might cause a slowdown. The reason is
- that the access model to the extension/SAPI own globals as well as the
- access to the core globals is determined in the compilation phase depending
- on whether ZEND_ENABLE_STATIC_TSRMLS_CACHE macro is defined.
-
- Due to the current compiler evolution state, the TSRMLS_CACHE pointer
- (when implemented) has to be present and updated in every binary unit which
- is not compiled statically into PHP. So any DLL, DSO, EXE, etc. has to take
- care about defining and updating it's TSRMLS cache. An update should happen
- before any globals was accessed.
-
- Porting an extension or SAPI is usually as easy as removing all the TSRMLS_*
- occurrences and integrating the macros mentioned above. However if tsrm_ls
- is used explicitly, its usage can be considered obsolete in most cases.
- Additionally, if an extension triggers its own threads, TSRMLS_CACHE shouldn't
- be passed to that threads directly.
-
- When working with CTOR/DTOR for the extension globals, only the data passed
- as parameters should be touched. For example, don't use code like
- free(MYEXT_G(vars)); inside globals destructor, as it possibly can destroy
- the data from a wrong thread. Instead use the pointer to the data delivered
- into the destructor. So the previous example could look like
- free(my_struct->vars); given the income was casted to (struct my_struct *).
-
- A new macro was introduced to simplify the declaration to the extension
- globals. A simplified declaration looks as follows
-
- #define MYEXT_G(v) ZEND_MODULE_GLOBALS_ACCESSOR(myext, v)
-
- Another new macro ZEND_MODULE_GLOBALS_BULK(myext) delivers the corresponding
- globals struct as a whole.
-
- Two new storage specifiers was introduced.
-
- ZEND_EXT_TLS - expand to an appropriate thread specific storage specifier in
- the thread safe build, expands to empty in a non thread safe
- build.
- ZEND_TLS - expands to an appropriate thread specific storage specifier
- with static visibility in the thread safe build, expands to
- static specifier in a non thread safe build.
-
- Variables declared with these storage specifiers can not be shared across
- threads. While ZEND_TLS enforces the local scope visibility, ZEND_EXT_TLS
- pertains to the visiblity across several compilation units. In both cases,
- there's no portable way to achieve the visibility across shared objects.
- Thus, these specifiers are not compatible with ZEND_API and PHPAPI specifiers.
-
- q. gc_collect_cycles() is now a function pointer, and can be replaced in the
- same manner as zend_execute_ex() if needed (for example, to include the
- time spent in the garbage collector in a profiler). The default
- implementation has been renamed to zend_gc_collect_cycles(), and is
- exported with ZEND_API.
-
- r. In accordance with general use of size_t as string length, all PDO API
- functions now use size_t for string length.
-
- s. Removed ZEND_REGISTER/FETCH_RESOURCE, use zend_fetch_resource and
- and zend_register_resource instead, zend_fetch_resource accepts a zend_resource *
- as first argument, if you still need to fetch a resource from zval, use
- zend_fetch_resource_ex. More details can be found in Zend/zend_list.c.
-
- t. Optimized strings concatenation.
- ZEND_ADD_STRING/VAR/CHAR are replaced with ZEND_ROPE_INIT, ZEND_ROPE_ADD,
- ZEND_ROPE_END.
- Instead of reallocation and copying string on each ZEND_ADD_STRING/VAR/CAHR,
- collect all the strings and then allocate and construct the resulting string once.
-
- u. Streams changes
- - It is possible to do blocking reads on Windows pipes. It can be done either
- using context stream option PHP_STREAM_OPTION_PIPE_BLOCKING or
- adding STREAM_USE_BLOCKING_PIPE when opening the stream.
-
- v. Sort algorithm changes
- - Improved zend_qsort(using hybrid sorting algo) for better performance,
- and also renamed zend_qsort to zend_sort.
- - Added stable sorting algo zend_insert_sort.
-
========================
2. Build system changes
========================
b. Windows build system changes
- - Besides Visual Studio, building with Clang or Intel Composer is now
- possible. To enable an alternative toolset, add the option
- --with-toolset=[vs,clang,icc] to the configure line. The default
- toolset is vs. Still clang or icc need the correct environment
- which involves many tools from the vs toolset.
-
- The toolset option is supported by phpize as well.
-
- AWARENESS The only recommended and supported toolset to produce production
- ready binaries is Visual Studio. Still other compilers can be used now for
- testing and analyzing purposes.
-
- - configure.js now produces response files which are passed to the linker
- and library manager. This solves the issues with the long command lines
- which can exceed the OS limit.
-
- - with clang toolset, an option --with-uncritical-warn-choke is available,
- which suppresses the most frequent false positive warnings
-
- - the --with-mp option will by default utilize all the available cores. It's
- enabled by default for release builds and can be disabled with the special
- "disable" keyword.
-
========================
3. Module changes
========================
- Session:
-
- - PS_MOD_UPDATE_TIMESTAMP() session save handler definition is added. New
- save handler should use PS_MOD_UPDATE_TIMESTAMP() definition. Save handler
- must not refer/change PS() variables directly from save handler. Use
- parameters.
- - PS_MOD()/PS_MOD_SID() macro exist only for transition. Beware these
- save handlers are less secure and slower than PS_MOD_UPDATE_TIMESTAMP().
- - PS(invalid_session_id) was removed. It was never worked as it supposed.
- To report invalid session ID, use PS_VALIDATE_SID() handler.
- - PS_VALIDATE_SID() defines session ID validation handler. This handler
- must validate if requested session ID exists in session data storage or not.
- Do not access PS(id) directly, but use this handler and it's parameter.
- - PS_UPDATE_TIMESTAMP() defines timestamp updating handler. This handler
- must update session data timestamp for GC if it is needed. e.g. Memcache
- updates timestamp on read, so it does not need to update timestamp. Return
- SUCCESS simply for this case.
- - PS_CREATE_SID() should check session ID collision. Return NULL for failure.
- - More documentation can be found in ext/session/mod_files.c as comments.
- mod_files.c may be used as reference implementation.
-
- Openssl:
- - several ext/openssl functions require the inclusion of the applink shim
- as documented in the OpenSSL FAQ https://www.openssl.org/support/faq.html#PROG2
- to properly work on Windows. While this primarily affects the OpenSSL
- functionality, the shim needs to be included into the executable file
- which loads the extension DLL, not into the extension DLL itself. Alternatively
- it can be compiled and linked with the main program as a separate object file.
- More information and explanation in the linked OpenSSL FAQ.
-
- Thus, this primarily affects any WAMP or other redistributions bundling the
- official PHP release zipballs or building from sources. The applink shim is
- already integrated with all the PHP executables from the official distribution
- starting with 7.0.0beta1.
-
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