PHP RFC: Deprecations for PHP 7.4
- Date: 26th June, 2018
- Status: In Draft
This is a draft RFC for multiple deprecations targeting PHP 7.4. The RFC proposes to deprecate the listed functionality in PHP 7.4 and remove it in PHP 8.
The following list provides a short overview of the functionality targeted for deprecation, while more detailed explanation is provided in the Proposal section:
- The 'real' type
- Magic quotes legacy
INPUT_REQUESTinput types for the filter extension
mb_strrpos()with encoding as 3rd argument
implode()parameter order mix
The following are still Work-In-Progress and ideas:
- Second parameter of spl_autoload() and its associated function spl_autoload_extensions()
- allow_url_include ini directive
- Function variants that already exists as constants (e.g. php_sapi_name(), phpversion(), pi())
Each feature proposed for deprecation is voted separately. Each vote requires a 2/3 majority, independently of whether it is a language or standard library change. All votes refer to deprecation in PHP 7.4 and removal in PHP 8.0.
enable_dl php.ini directive
enable_dl php.ini directive controls whether or not the
dl() function is available. However as of PHP 5.3, the
dl() function was limited to the CLI and Embed SAPIs and between PHP 5.3.9 and 7.0.0, it was also available in the FPM SAPI.
This means that the
enable_dl effectively has no greater meaning as it will never be available in a shared environment anyway, as any CLI user could easily bypass it anyway.
Proposal: Add a deprecation warning if
enable_dl is non zero at start-up and when using CLI or Embed.
The 'real' type
Currently PHP has a float data type, with 2 additional aliases: double & real. The latter is very very rarely used and should be deprecated. This includes both the
(real) type-cast and the
is_real() function. Currently the
settype() function does not support the 'real' string, so it is not affected.
Upgrading is relatively easy and can be done by replacing all
(real) type-casts with
(float) and all
is_real() calls with
Proposal: Add a deprecation warning for each time the
(real) type-cast is used and each time the
is_real() function is called.
The hebrev() and hebrevc() functions
hebrevc() functions are functions that helped make websites hebrew before browsers properly supported RTL, by simply converting the nature of RTL to LTR writing for easier display on websites. All modern browsers nowadays properly support unicode and RTL text direction and therefore it seems reasonable to deprecate these functions.
hebrevc() function is essentially the same as calling
nl2br() on the result of a
Proposal: Add a deprecation warning if either
hebrevc() is called.
Magic quotes legacy
PHP's infamous magic_quotes configuration was removed in PHP 5.4 and the function implementations of checking whether or not these settings have been enabled have returned false since then. With PHP 7.0 not having magic_quotes at all, it is time to deprecate these functions and remove them entirely.
This should effectively only hit legacy code bases prior to PHP 5.4, which is running non supported versions of PHP.
Proposal: Add a deprecation warning if either
get_magic_quotes_runtime() is called.
array_key_exists() with objects
The documentation already marks the use of array_key_exists() with objects as legacy behavior:
For backward compatibility reasons, array_key_exists() will also return TRUE if
keyis a property defined within an object given as
array. This behaviour should not be relied upon, and care should be taken to ensure that
arrayis an array. To check whether a property exists in an object, use
array_key_exists() on objects also has some technical issues: It operates directly on mangled property names and does not respect property visibility. Furthermore it does not take into account differences in normalization between array and object keys, so that incorrect results may be returned for properties with integral keys.
Proposal: Throw a deprecation warning if an object is passed to
Magic quotes were deprecated all the way back in PHP 5.3 and later removed in PHP 5.4. The filter extension implements a sanitization filter that mimics this behavior of
magic_quotes by calling
addslashes() on the input in question.
As of PHP 7.3, a new alias of this filter was added
FILTER_SANITIZE_ADD_SLASHES) to help ease the migration and allow us to move away from the
magic_quotes name as calling
addslashes() can still potentially be useful.
Proposed action: Emit a deprecation notice each time the
FILTER_SANITIZE_MAGIC_QUOTES filter is used and advice users to use the
INPUT_SESSION & INPUT_REQUEST input types for the filter extension
The filter extension implements a set of
INPUT_XXX constants for telling the source of where the input is coming from. However, the
INPUT_REQUEST inputs were never implemented but their constants are and simply just emits an
E_WARNING when used.
Impact: Minimal as they do not serve any function and functionality relying on this is broken (non functional).
Proposed action: Keep the
E_WARNING and mention that these will be removed in a future version of PHP.
This function with an Apache-specific name is also available in other SAPIs, even though it is also available under the SAPI-independent name
getallheaders(). The SAPI-specific function should be removed in favor of the more general one.
Proposed action: Mark
apache_request_headers() as deprecated.
register_argc_argv ini directive
This ini setting controls whether the
$argc variables are registered. On CLI SAPIs these contain the CLI arguments, on non-CLI SAPIs they contain the
GET string parsed as if it were CLI arguments.
On CLI SAPIs
register_argc_argv=1 is a “hardcoded” ini setting, which means that it cannot be disabled through php.ini, it may only be overridden on the command line using
-d register_argc_argv=0. For other SAPIs this ini setting also defaults to on, but both
php.ini-production disable it.
This ini setting should be removed for two reasons: On CLI SAPIs it is a liability, which prevents us from strictly guaranteeing the availability of
$argv. On non-CLI SAPIs this functionality seems to be of questionable usefulness, while also negatively impacting performance and perpetuating questionable security practices.
Proposed action: Unclear. We could generate a deprecation notice if this setting is enabled on non-CLI SAPIs, however that would make the default behavior generate a deprecation notice. It might be possible to also change the default behavior at the same time.
Reflection export() methods
Reflector interface, which is implemented by all reflection classes, specifies two methods:
export(). The latter is a static method which, ostensibly, does not accept arguments. In reality this static methods is implemented with varying signatures in each subclass, something which would normally result in an incompatible signature error. However, the implementation uses an internal mechanism to suppress this error.
export() methods are essentially equivalent to a combination of the class constructor and
__toString(). For example:
ReflectionFunction::export('foo'); // same as echo new ReflectionFunction('foo'), "\n"; $str = ReflectionFunction::export('foo', true); // same as $str = (string) new ReflectionFunction('foo');
As such, the
export() method is wholly unnecessary, confusing, and violates PHP's own inheritance rules.
Proposed action: In PHP 7.4 remove the method from the
Reflector interface and deprecate all implementations of the method in reflection classes. In PHP 8 also remove the implementations.
mb_strrpos() with encoding as 3rd argument
The documentation for
The encoding parameter was moved from the third position to the fourth in PHP 5.2.0. For backward compatibility, encoding can be specified as the third parameter, but doing so is deprecated and will be removed in the future.
However, this deprecation has never been realized in the implementation. The need to support both signatures makes this parameter behave subtly different from other integer parameters (e.g. it is not subject to strict types). As little software is expected to support both PHP 7.4 and PHP 5.1, enforcing the new signature does not pose a significant backwards compatibility concern.
Proposed action: In PHP 7.4 throw a deprecation warning if an encoding is passed as the 3rd argument. In PHP 8 change the argument to accept an integer.
This constant is the old way of detecting current class name.
Since PHP 5.5,
__CLASS__ is equivalent to
__CLASS__ constant in favor of
This function is the old way of detecting current class name during LSB.
Since PHP 5.5, using
get_called_class() is equivalent to
get_called_class() in favor of
is_writeable() function is an alias of
is_writeable() is notorious in the sense that it has a spelling mistake in its name and since the introduction of
is_writable() been considered soft deprecated.
Proposal: Deprecate the alias
implode() parameter order mix
implode() function historically supports passing the
$pieces parameters in any order, for consistency with
explode(), this is inconsistent and the only function in the standard library exhibits this behavior and it should be amended.
This naturally also affects the
Proposal: Emit a deprecation warning if calling
Backward Incompatible Changes
For PHP 7.4 additional deprecation notices will appear. For PHP 8.0 the previously deprecated functionality will no longer be available.
Each of the bullet points above will get a separate vote. All votes will require a 2/3 supermajority, independently of whether they are language changes or not.
- 2018-07-05: Added
array_key_exists()with object arg (majkl)