Edit report at https://bugs.php.net/bug.php?id=60139&edit=1
ID: 60139 Patch added by: dmi...@php.net Reported by: lbarn...@php.net Summary: Anonymous functions create cycles not detected by the GC Status: Assigned Type: Bug Package: Performance problem PHP Version: 5.4.0beta2 Assigned To: dmitry Block user comment: N Private report: N New Comment: The following patch has been added/updated: Patch Name: gc-closure.diff Revision: 1320059056 URL: https://bugs.php.net/patch-display.php?bug=60139&patch=gc-closure.diff&revision=1320059056 Previous Comments: ------------------------------------------------------------------------ [2011-10-31 08:44:09] dmi...@php.net The following patch has been added/updated: Patch Name: gc-closure.diff Revision: 1320050649 URL: https://bugs.php.net/patch-display.php?bug=60139&patch=gc-closure.diff&revision=1320050649 ------------------------------------------------------------------------ [2011-10-26 10:36:24] lbarn...@php.net Description: ------------ In the following Script 1 and Script 2, the created objects are not destructed until the engine shutdowns because of a reference cycle. The objects hold a reference to an anonymous function that itself hold a reference to the object. It seems that the garbage collector is unable to break the cycle. Script 3 doesn't leak memory because the anonymous function doesn't hold a reference to the object. Test script: --------------- # Script 1 (leaks with php5.4) <?php class Foo { public $x; public function __construct() { $this->x = function() {}; } } echo memory_get_usage(), "\n"; for ($i = 0; $i < 1000; ++$i) { new Foo; } gc_collect_cycles(); echo memory_get_usage(), "\n"; ?> # Script 2 (leaks with php5.3) <?php class Foo { public $x; public function __construct() { $self = $this; $this->x = function() use ($self) {}; } } echo memory_get_usage(), "\n"; for ($i = 0; $i < 1000; ++$i) { new Foo; } gc_collect_cycles(); echo memory_get_usage(), "\n"; ?> # Script 3 (no leak) <?php class Foo { public $x; public function __construct() { $this->x = get_fun(); } } function get_fun() { return function() {}; } echo memory_get_usage(), "\n"; for ($i = 0; $i < 1000; ++$i) { new Foo; } gc_collect_cycles(); echo memory_get_usage(), "\n"; ?> Expected result: ---------------- Memory usage before and after is approximatel the same: 121040 121152 Actual result: -------------- Objects are never freed and memory usage increases: 120724 417640 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=60139&edit=1