UPGRADING

PHP 8.3 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
14. Performance Improvements

========================================
1. Backward Incompatible Changes
========================================

- Core:
  . Programs that were very close to overflowing the call stack may now throw an
    Error when using more than
    `zend.max_allowed_stack_size-zend.reserved_stack_size` bytes of stack
    (`fiber.stack_size-zend.reserved_stack_size` for fibers).
  . Class constants can now be accessed dynamically using the C::{$name} syntax.
    RFC: https://wiki.php.net/rfc/dynamic_class_constant_fetch
  . Executing proc_get_status() multiple times will now always return the right
    value on posix systems. Previously, only the first call of the function
    returned the right value. Executing proc_close() after proc_get_status() will
    now also return the right exit code. Previously this would return -1.
    Internally, this works by caching the result on posix systems. If you want
    the old behaviour, you can check the "cached" key in the array returned by
    proc_get_status() to check whether the result was cached.
  . Zend Max Execution Timers is now enabled by default for ZTS builds on
    Linux.
  . Uses of traits with static properties will now redeclare static properties
    inherited from the parent class. This will create a separate static property
    storage for the current class. This is analogous to adding the static
    property to the class directly without traits.
  . Assigning a negative index n to an empty array will now make sure that the
    next index is n+1 instead of 0.
  . Static variable initializers can now contain arbitrary expressions.
    RFC: https://wiki.php.net/rfc/arbitrary_static_variable_initializers

- FFI:
  . C functions that have a return type of void now return null instead of
    returning the following object object(FFI\CData:void) { }

========================================
2. New Features
========================================

- Core
  . Anonymous classes may now be marked as readonly.
  . Readonly properties can now be reinitialized during cloning.
    RFC: https://wiki.php.net/rfc/readonly_amendments
  . Class, interface, trait, and enum constants now support type
    declarations. RFC: https://wiki.php.net/rfc/typed_class_constants
  . Closures created from magic methods can now accept named arguments.

- Posix
  . posix_getrlimit() now takes an optional $res parameter to allow fetching a
    single resource limit.
  . posix_isatty() now raises type warnings for integers following the usual ZPP semantics
  . posix_ttyname() now raises type warnings for integers following the usual ZPP semantics
    and value warnings for invalid file descriptor integers.

========================================
3. Changes in SAPI modules
========================================

- $_SERVER['SERVER_SOFTWARE'] value from the built-in CLI server changed
  to make it compliant with RFC3875.

========================================
4. Deprecated Functionality
========================================

- Intl
  . The U_MULTIPLE_DECIMAL_SEP*E*RATORS constant had been deprecated, using
    the U_MULTIPLE_DECIMAL_SEP*A*RATORS instead is recommended.

========================================
5. Changed Functions
========================================

- Core:
  . gc_status() has added the following 4 fields:
    "running" => bool
    "protected" => bool
    "full" => bool
    "buffer_size" => int
    See GH-9336
  . class_alias() now supports creating an alias of an internal class.
  . Setting `open_basedir` at runtime using `ini_set('open_basedir', ...);` no
    longer accepts paths containing the parent directory (`..`). Previously,
    only paths starting with `..` were disallowed. This could easily be
    circumvented by prepending `./` to the path.

- Dom:
  . Changed DOMCharacterData::appendData() tentative return type to true.

- Intl:
  . datefmt_set_timezone (and its alias IntlDateformatter::setTimeZone) 
    now returns true on success, previously null was returned.
  . IntlBreakiterator::setText() now returns false on failure, previously
    null was returned.
    now returns true on sucess, previously null was returned.
  . IntlChar::enumCharNames is now returning a boolean.
    Previously it returned null on success and false on failure.

- MBString:
  . mb_strtolower, mb_strtotitle, and mb_convert_case implement conditional
    casing rules for the Greek letter sigma. For mb_convert_case, conditional
    casing only applies to MB_CASE_LOWER and MB_CASE_TITLE modes, not to
    MB_CASE_LOWER_SIMPLE and MB_CASE_TITLE_SIMPLE.
  . mb_decode_mimeheader interprets underscores in QPrint-encoded MIME
    encoded words as required by RFC 2047; they are converted to spaces.
    Underscores must be encoded as "=5F" in such MIME encoded words.
  . In rare cases, mb_encode_mimeheader will transfer-encode its input
    string where it would pass it through as raw ASCII in PHP 8.2.
  . mb_encode_mimeheader no longer drops NUL (zero) bytes when
    QPrint-encoding the input string. This previously caused strings in
    certain text encodings, especially UTF-16 and UTF-32, to be
    corrupted by mb_encode_mimeheader.
  . mb_detect_encoding's "non-strict" mode now behaves as described in the
    documentation. Previously, it would return false if the same byte
    (for example, the first byte) of the input string was invalid in all
    candidate encodings. More generally, it would eliminate candidate
    encodings from consideration when an invalid byte was seen, and if the
    same input byte eliminated all remaining encodings still under
    consideration, it would return false. On the other hand, if all candidate
    encodings but one were eliminated from consideration, it would return the
    last remaining one without regard for how many encoding errors might be
    encountered later in the string. This is different from the behavior
    described in the documentation, which says: "If strict is set to false,
    the closest matching encoding will be returned."

- mysqli:
  . mysqli_fetch_object now raises a ValueError instead of an Exception when the constructor_args
    argument is non empty with the class not having constructor.
  . mysqli_poll now raises a ValueError when the read nor error arguments are passed.

- PGSQL:
  . pg_fetch_object now raises a ValueError instead of an Exception when the constructor_args
    argument is non empty with the class not having constructor.
  . pg_insert now raises a ValueError instead of a WARNING when the table specified is invalid.
  . pg_insert and pg_convert raises a ValueError or a TypeError instead of a WARNING when the
    value/type of a field does not match properly with a PostGreSQL's type.

- Standard:
  . E_NOTICEs emitted by unserialize() have been promoted to E_WARNING.
    RFC: https://wiki.php.net/rfc/improve_unserialize_error_handling
  . unserialize() now emits a new E_WARNING if the input contains unconsumed
    bytes.
    RFC: https://wiki.php.net/rfc/unserialize_warn_on_trailing_data
  . array_pad() is now only limited by the maximum number of elements an array
    can have. Before, it was only possible to add at most 1048576 elements at a
    time.
  . strtok() raises a warning in the case token is not provided when starting tokenization.
  . password_hash() will now chain the underlying Random\RandomException
    as the ValueError’s $previous Exception when salt generation fails.
  . proc_open() $command array must now have at least one non empty element.
  . array_sum() and array_product() now warn when values in the array cannot be converted to int/float.
    Previously arrays and objects where ignored whilst every other value was cast to int.
    Moreover, objects that define a numeric cast (e.g. GMP) are now casted instead of ignored.
    RFC: https://wiki.php.net/rfc/saner-array-sum-product

========================================
6. New Functions
========================================

- JSON:
  . Added json_validate(), which returns whether the json is valid for
    the given $depth and $options.
    RFC: https://wiki.php.net/rfc/json_validate

- Posix:
  . Added posix_sysconf call to get runtime informations.
  . Added posix_pathconf call to get configuration value from a directory/file.
  . Added posix_fpathconf call to get configuration value from a file descriptor.
  . Added posix_eaccess call to check the effective user id's permission for a path.

- Random:
  . Added Randomizer::getBytesFromString().
    RFC: https://wiki.php.net/rfc/randomizer_additions
  . Added Randomizer::nextFloat(), ::getFloat(), and IntervalBoundary.
    RFC: https://wiki.php.net/rfc/randomizer_additions
  . Changed mt_srand() and srand() to not check the number of arguments to
    determine whether a random seed should be used. Passing null will generate
    a random seed, 0 will use zero as the seed. The functions are now consistent
    with Mt19937::__construct().

- Reflection:
  . Return type of ReflectionClass::getStaticProperties() is no longer nullable.

- Sockets:
  . Added socket_atmark to checks if the socket is OOB marked.

========================================
7. New Classes and Interfaces
========================================

========================================
8. Removed Extensions and SAPIs
========================================

========================================
9. Other Changes to Extensions
========================================

========================================
10. New Global Constants
========================================

- Intl:
  . MIXED_NUMBERS (Spoofchecker).
  . HIDDEN_OVERLAY (Spoofchecker).

- OpenSSL:
  . OPENSSL_CMS_OLDMIMETYPE
  . PKCS7_NOOLDMIMETYPE

- PCNTL:
  . SIGINFO

- PGSQL:
  . PGSQL_TRACE_SUPPRESS_TIMESTAMPS.
  . PGSQL_TRACE_REGRESS_MODE.
  . PGSQL_ERRORS_SQLSTATE.

- Posix:
  . POSIX_SC_ARG_MAX.
  . POSIX_SC_PAGESIZE.
  . POSIX_SC_NPROCESSORS_CONF.
  . POSIX_SC_NPROCESSORS_ONLN.

- Sockets:
  . SO_ATTACH_REUSEPORT_CBPF (Linux only).
  . TCP_QUICKACK (Linux only).
  . IP_DONTFRAG (FreeBSD only).
  . IP_MTU_DISCOVER (Linux only).
  . IP_PMTUDISC_DO (Linux only).
  . IP_PMTUDISC_DONT (Linux only).
  . IP_PMTUDISC_WANT (Linux only).
  . IP_PMTUDISC_PROBE (Linux only).
  . IP_PMTUDISC_INTERFACE (Linux only).
  . IP_PMTUDISC_OMIT (Linux only).
  . AF_DIVERT (FreeBSD only).
  . SOL_UDPLITE.
  . UDPLITE_RECV_CSCOV.
  . UDPLITE_SEND_CSCOV.
  . SO_RERROR (NetBSD only).
  . SO_ZEROIZE (OpenBSD only).
  . SO_SPLICE (OpenBSD only).
  . TCP_REPAIR (Linux only).
  . SO_REUSEPORT_LB (FreeBSD only).
  . IP_BIND_ADDRESS_NO_PORT (Linux only).

========================================
11. Changes to INI File Handling
========================================

- zend.max_allowed_stack_size
  . New INI directive to set the maximum allowed stack size. Possible
    values are `0` (detect the process or thread maximum stack size), `-1`
    (no limit), or a positive number of bytes. The default is `0`. When it
    is not possible to detect the the process or thread maximum stack size,
    a known system default is used. Setting this value too high has the same
    effect as disabling the stack size limit. Fibers use fiber.stack_size
    as maximum allowed stack size. An Error is thrown when the process call
    stack exceeds `zend.max_allowed_stack_size-zend.reserved_stack_size`
    bytes, to prevent stack-overflow-induced segmentation faults, with
    the goal of making debugging easier. The stack size increases during
    uncontrolled recursions involving internal functions or the magic methods
    __toString, __clone, __sleep, __destruct.  This is not related to stack
    buffer overflows, and is not a security feature.

- zend.reserved_stack_size
  . New INI directive to set the reserved stack size, in bytes. This is
    subtracted from the max allowed stack size, as a buffer, when checking the
    stack size.

========================================
12. Windows Support
========================================

========================================
13. Other Changes
========================================

- Core:
  . An Error is now thrown when the process call stack exceeds a certain size,
    to prevent stack-overflow-induced segmentation faults, with the goal of
    making debugging easier. The maximum allowed stack size is controlled
    by the INI directives zend.max_allowed_stack_size, zend.reserved_stack_size,
    and fiber.stack_size.

- FFI:
  . FFI::load() is now allowed during preloading when opcache.preload_user is the
    current system user. Previously, calling FFI::load() was not possible during
    preloading if the opcache.preload_user directive was set.

- Opcache:
  . In the cli and phpdbg SAPIs, preloading does not require the
    opcache.preload_user directive to be set anymore when running as root. In
    other SAPIs, this directive is required when running as root because
    preloading is done before the SAPI switches to an unprivileged user.

- Streams:
  . Blocking fread() on socket connection returns immediately if there are
    any buffered data instead of waiting for more data.

========================================
14. Performance Improvements
========================================