Bug #74690 [Ver]: PHP throws reference notice when using namespaces.

Edit report at https://bugs.php.net/bug.php?id=74690&edit=1 ID: 74690 Updated by: nikic@php.net Reported by: contact at greg dot md Summary: PHP throws reference notice when using namespaces. Status: Verified Type: Bug Package: Scripting Engine problem Operating System: Mac PHP Version: 7.1.5 Block user comment: N Private report: N New Comment: No, the notice should occur, because call_user_func_array() does not return by reference. You are right that it does not occur because we're effectively compiling this to a direct call without the indirection in the non-namespaced case, but this doesn't change the fact that a notice should be thrown. As a rule of thumb, if cuf/a behaves differently depending on whether it's in a namespace or not, then the namespaced behavior is always correct. That being said, I don't think we're going to fix this. Previous Comments: ------------------------------------------------------------------------ [2017-06-02 15:49:41] requinix@php.net More specific: the notice is only in a namespace and with an unqualified "call_user_func_array". It does not warn outside of a namespace (or in the global namespace) or with the fully-qualified "\call_user_func_array". > The error is about the weird extra ampersand that is in front of the > "&call_user_func_array" . It is complaining that you're trying to reference > the > return value of the function by reference. That ampersand is required to properly use functions that return by-ref: one in the function declaration to return its value by-ref, then another in the assignment to assign by-ref. The latter is really more of a =& operator but with optional whitespace between the two characters. This is all documented: https://secure.php.net/manual/en/language.references.return.php > The bug here is that the notice does not occur in the non-namespaced case. The notice *shouldn't* occur. call_user_func and call_user_func_array get special treatment during compilation - a discrepancy between there and the ZEND_ASSIGN_REF handler is why there's a notice. If it were a regular function call then there wouldn't be any problem. https://3v4l.org/D0Chh ------------------------------------------------------------------------ [2017-06-02 10:07:56] contact at greg dot md It is definitely a bug. If you will remove namespace from the example, it will work as expected and will return the reference of the $foo in $bar, which is expected. With that namespace at the top of the file looks like I can not return by reference using the "&call_user_func_array". Please do the same test with the namespace in the top of the file and without it. ------------------------------------------------------------------------ [2017-06-02 10:02:02] nikic@php.net The bug here is that the notice does not occur in the non-namespaced case. ------------------------------------------------------------------------ [2017-06-02 09:53:34] danack@php.net The error is about the weird extra ampersand that is in front of the "&call_user_func_array" . It is complaining that you're trying to reference the return value of the function by reference. ------------------------------------------------------------------------ [2017-06-02 09:14:15] contact at greg dot md Description: ------------ When a namespace is defined in a file and you want to return a reference, the "PHP Notice: Only variables should be assigned by reference" is thrown. If I delete the namespace, then it works good. Test script: --------------- <?php namespace Bar; $foo = 'foo'; $bar = &call_user_func_array(function &() use (&$foo) { return $foo; }, []); $bar = 'bar'; echo $foo . PHP_EOL; Expected result: ---------------- bar Actual result: -------------- PHP Notice: Only variables should be assigned by reference in /htdocs/php-app/vendor/greg-md/php-framework/test.php on line 9 PHP Stack trace: PHP 1. {main}() /htdocs/php-app/vendor/greg-md/php-framework/test.php:0 Notice: Only variables should be assigned by reference in /htdocs/php-app/vendor/greg-md/php-framework/test.php on line 9 Call Stack: 0.0002 353152 1. {main}() /htdocs/php-app/vendor/greg-md/php-framework/test.php:0 foo ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74690&edit=1