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[2015-08-28 09:00 UTC] lolautruche at gmail dot com
Description:
------------
In PHP 7, passing variables assigned by reference to call_user_func_array() (as part of arguments) now triggers a warning :
"Warning: Parameter 1 to ... expected to be a reference, value given in..."
It worked fine in PHP 5.6.
Current workaround is to explicitly pass the value by reference (see code).
Not sure if this is on purpose, but I couldn't find any mention in the UPGRADING doc about this specifically.
Test script:
---------------
<?php
$foo = function (&$arg) {
var_dump($arg);
};
$a = 'bar';
$b =& $a;
// Warning: Parameter 1 to {closure}() expected to be a reference, value given in /Users/lolautruche/Desktop/reference.php on line 8
call_user_func_array($foo, [$b]);
// Works fine
call_user_func_array($foo, [&$a]);
Expected result:
----------------
string(3) "bar"
string(3) "bar"
Actual result:
--------------
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /Users/lolautruche/Desktop/reference.php on line 10
string(3) "bar"
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Last updated: Sun Oct 26 00:00:01 2025 UTC |
Thinking about this, the behavior of PHP 5.x is strange. When a function accepts a value by reference, the only check should be to ensure that a variable is passed, otherwise "Fatal error: Only variables can be passed by reference" should be raised, e.g.: function by_ref(&$arg) { $arg = "changed"; }; by_ref("foo"); // Triggers the fatal error $x = "orig"; by_ref($x); // Changes $x to "changed" A function using "value by reference" doesn't mean that a reference should be passed on but that the local variable to the function should be treated as a reference to the original one. Hence I think that in ext/standard/tests/general_functions/call_user_func_array_variation_001.phpt, the second test: "Calling by_ref() with unreferenced argument" should NOT emit the warning "Warning: Parameter 1 to by_ref() expected to be a reference" either. Note that in PHP 5, one can call: call_user_func_array("by_ref", ["test"]); This is inconsistent as well, "Fatal error: Only variables can be passed by reference" should have been triggered.