This project backports features found in the latest PHP versions and provides compatibility layers for some extensions and functions. It is intended to be used when portability across PHP versions and extensions is desired.
Polyfills are provided for:
- the
apcu
extension when the legacyapc
extension is installed; - the
ctype
extension when PHP is compiled without ctype; - the
mbstring
andiconv
extensions; - the
uuid
extension; - the
MessageFormatter
class and themsgfmt_format_message
functions; - the
Normalizer
class and thegrapheme_*
functions; - the
utf8_encode
andutf8_decode
functions from thexml
extension or PHP-7.2 core; - the
Collator
,NumberFormatter
,Locale
andIntlDateFormatter
classes; - the
intl_error_name
,intl_get_error_code
,intl_get_error_message
andintl_is_failure
functions; - the
idn_to_ascii
andidn_to_utf8
functions; - the
hex2bin
function, theCallbackFilterIterator
,RecursiveCallbackFilterIterator
andSessionHandlerInterface
classes introduced in PHP 5.4; - the
array_column
,boolval
,json_last_error_msg
andhash_pbkdf2
functions introduced in PHP 5.5; - the
password_hash
andpassword_*
related functions introduced in PHP 5.5, provided by theircmaxell/password-compat
package; - the
hash_equals
andldap_escape
functions introduced in PHP 5.6; - the
*Error
classes, theerror_clear_last
,preg_replace_callback_array
andintdiv
functions introduced in PHP 7.0; - the
random_bytes
andrandom_int
functions introduced in PHP 7.0, provided by theparagonie/random_compat
package; - the
PHP_INT_MIN
constant introduced in PHP 7.0, - the
SessionUpdateTimestampHandlerInterface
interface introduced in PHP 7.0, - the
is_iterable
function introduced in PHP 7.1; - a
Binary
utility class to be used when compatibility withmbstring.func_overload
is required; - the
spl_object_id
andstream_isatty
functions introduced in PHP 7.2; - the
sapi_windows_vt100_support
function (Windows only) introduced in PHP 7.2; - the
PHP_OS_FAMILY
constant introduced in PHP 7.2; - the
is_countable
function introduced in PHP 7.3; - the
array_key_first
andarray_key_last
functions introduced in PHP 7.3; - the
hrtime
function introduced in PHP 7.3; - the
JsonException
class introduced in PHP 7.3; - the
get_mangled_object_vars
,mb_str_split
andpassword_algos
functions introduced in PHP 7.4; - the
fdiv
function introduced in PHP 8.0; - the
ValueError
class introduced in PHP 8.0; - the
FILTER_VALIDATE_BOOL
constant introduced in PHP 8.0;
It is strongly recommended to upgrade your PHP version and/or install the missing extensions whenever possible. This polyfill should be used only when there is no better choice or when portability is a requirement.
To write portable code between PHP5 and PHP7, some care must be taken:
\*Error
exceptions must be caught before\Exception
;- after calling
error_clear_last()
, the result of$e = error_get_last()
must be verified usingisset($e['message'][0])
instead ofnull !== $e
.
When using Composer to manage your dependencies, you
should not require
the symfony/polyfill
package, but the standalone ones:
symfony/polyfill-apcu
for using theapcu_*
functions,symfony/polyfill-ctype
for using the ctype functions,symfony/polyfill-php54
for using the PHP 5.4 functions,symfony/polyfill-php55
for using the PHP 5.5 functions,symfony/polyfill-php56
for using the PHP 5.6 functions,symfony/polyfill-php70
for using the PHP 7.0 functions,symfony/polyfill-php71
for using the PHP 7.1 functions,symfony/polyfill-php72
for using the PHP 7.2 functions,symfony/polyfill-php73
for using the PHP 7.3 functions,symfony/polyfill-php74
for using the PHP 7.4 functions,symfony/polyfill-php80
for using the PHP 8.0 functions,symfony/polyfill-iconv
for using the iconv functions,symfony/polyfill-intl-grapheme
for using thegrapheme_*
functions,symfony/polyfill-intl-idn
for using theidn_to_ascii
andidn_to_utf8
functions,symfony/polyfill-intl-icu
for using the intl functions and classes,symfony/polyfill-intl-messageformatter
for using the intl messageformatter,symfony/polyfill-intl-normalizer
for using the intl normalizer,symfony/polyfill-mbstring
for using the mbstring functions,symfony/polyfill-util
for using the polyfill utility helpers.symfony/polyfill-uuid
for using theuuid_*
functions,
Requiring symfony/polyfill
directly would prevent Composer from sharing
correctly polyfills in dependency graphs. As such, it would likely install
more code than required.
This package is designed for low overhead and high quality polyfilling.
It adds only a few lightweight require
statements to the bootstrap process
to support all polyfills. Implementations are then loaded on-demand when
needed during code execution.
If your project requires a minimum PHP version it is advisable to add polyfills
for lower PHP versions to the replace
section of your composer.json
.
This removes any overhead from these polyfills as they are no longer part of your project.
The same can be done for polyfills for extensions that you require.
If your project requires php 7.0, and needs the mb extension, the replace section would look something like this:
{
"replace": {
"symfony/polyfill-php54": "1.99",
"symfony/polyfill-php55": "1.99",
"symfony/polyfill-php56": "1.99",
"symfony/polyfill-php70": "1.99",
"symfony/polyfill-mbstring": "1.99"
}
}
Polyfills are unit-tested alongside their native implementation so that feature and behavior parity can be proven and enforced in the long run.
This library is released under the MIT license.