Bug #67633 [Asn->Csd]: A foreach on an array returned from a function not doing copy-on-write

Edit report at https://bugs.php.net/bug.php?id=67633&edit=1 ID: 67633 Updated by: nikic@php.net Reported by: tim at siliconengine dot com Summary: A foreach on an array returned from a function not doing copy-on-write -Status: Assigned +Status: Closed Type: Bug Package: Arrays related Operating System: CentOS 6.5 PHP Version: 5.5.14 Assigned To: nikic Block user comment: N Private report: N New Comment: Automatic comment on behalf of nikic Revision: http://git.php.net/?p=php-src.git;a=commit;h=5e977e69e144ca92868ae73cd3563eb473b75937 Log: Fixed bug #67633 Previous Comments: ------------------------------------------------------------------------ [2014-07-16 15:11:57] tim at siliconengine dot com Description: ------------ When passing an array by value to a function, which immediately returns that array, and then using that return value in a foreach with a reference, it allows modifying the original array as if it was passed by reference. These variants work properly: ............. Variant 1 [same main body] function z($t) { // Force copy-on-write $t[0] .= 'x'; return $t; } ............. ............. Variant 2 $a = [ 'a', 'b', 'c' ]; $b = z($a); // Assigning to variable causes proper copy-on-write behavior foreach($b as &$x) { $x .= 'q'; } print_r($a); [same z function] ............. Test script: --------------- <?php $a = [ 'a', 'b', 'c' ]; foreach(z($a) as &$x) { $x .= 'q'; } print_r($a); function z($t) { return $t; } Expected result: ---------------- Array ( [0] => a [1] => b [2] => c ) Actual result: -------------- Array ( [0] => aq [1] => bq [2] => cq ) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=67633&edit=1