Bug->Doc #76028 [Opn->Ver]: call_user_func($a) and $a() behave differently

Edit report at https://bugs.php.net/bug.php?id=76028&edit=1 ID: 76028 Updated by: cmb@php.net Reported by: bburnichon at gmail dot com Summary: call_user_func($a) and $a() behave differently -Status: Open +Status: Verified -Type: Bug +Type: Documentation Problem Package: Scripting Engine problem Operating System: Linux PHP Version: 7.1 Block user comment: N Private report: N New Comment: > I just wished I knew this before. So yes, this is actually a documentation problem. Note that as of PHP 8.1.0 you can use self::foo(...) which is even better, since that callable is callable everywhere. For previous PHP versions, you can use the more verbose Closure::fromCallable([self::class, 'foo']) to have the same benefit. Previous Comments: ------------------------------------------------------------------------ [2018-02-28 17:54:36] bburnichon at gmail dot com Yes, that's what I've done once I discovered the issue. I just wished I knew this before. I've learnt it the hard way while refactoring an old class which was calling ``` $method = // Method from user input $callable = ['self', $method]; if (is_callable($callable)) { call_user_func($callable); } ``` to ``` $method = // Whitelisted method $callable = [self::class, $method]; $callable(); ``` ------------------------------------------------------------------------ [2018-02-28 17:39:09] cmb@php.net FWIW: don't use the string 'self', but rather self::class, see <https://3v4l.org/Xkkuf>. ------------------------------------------------------------------------ [2018-02-28 14:58:25] daverandom@php.net Related: https://wiki.php.net/rfc/consistent_callables ------------------------------------------------------------------------ [2018-02-28 14:38:40] bburnichon at gmail dot com Checked versions having the issue with 3v4l.org: https://3v4l.org/Ssgep ------------------------------------------------------------------------ [2018-02-28 14:33:43] bburnichon at gmail dot com Description: ------------ A callable can be defined as an array containing class and method. Calling call_user_func() with such an array has no issue. If you try to use the array as a callable, then 'self' loose its special meaning and an error is triggered saying class self does not exists. Test script: --------------- <?php class CallBySelf { public static function foo() { echo 'Foo', PHP_EOL; } public static function testCall() { $method = ['self', 'foo']; var_dump(is_callable($method)); echo 'Call via call_user_func: '; call_user_func($method); echo 'Direct call: '; $method(); } } CallBySelf::testCall(); Expected result: ---------------- Call via call_user_func: Foo Direct call: Foo Actual result: -------------- bool(true) Call via call_user_func: Foo Direct call: Fatal error: Class 'self' not found in /in/Ssgep on line 19 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=76028&edit=1