Bug #71818 [Asn->Csd]: Memory leak when array altered in destructor

Edit report at https://bugs.php.net/bug.php?id=71818&edit=1 ID: 71818 Updated by: davey@php.net Reported by: james dot harris at icecave dot com dot au Summary: Memory leak when array altered in destructor -Status: Assigned +Status: Closed Type: Bug Package: Scripting Engine problem Operating System: OSX PHP Version: 7.0.4 Assigned To: laruence Block user comment: N Private report: N New Comment: Automatic comment on behalf of dmitry@zend.com Revision: http://git.php.net/?p=php-src.git;a=commit;h=8fc934b0a1781bc0685775f4c476c6704d796a76 Log: Fixed bug #71818 (Memory leak when array altered in destructor) Previous Comments: ------------------------------------------------------------------------ [2016-07-14 09:08:25] dmitry@php.net Fixed in PHP-7.1. http://git.php.net/?p=php-src.git;a=commitdiff;h=8fc934b0a1781bc0685775f4c476c6704d796a76 The patch might be backported to PHP-7.0 after additional testing. ------------------------------------------------------------------------ [2016-07-14 09:05:57] dmitry@php.net Automatic comment on behalf of dmitry@zend.com Revision: http://git.php.net/?p=php-src.git;a=commit;h=8fc934b0a1781bc0685775f4c476c6704d796a76 Log: Fixed bug #71818 (Memory leak when array altered in destructor) ------------------------------------------------------------------------ [2016-04-15 01:39:11] james dot harris at icecave dot com dot au Those are the conditions under which the leak does NOT occur. Sorry, I worded it a bit backwards. I realise this is a bit academic and strange, and I've certainly worked around whatever code I found doing this (I can't remember what it was now), but I figured it was still worth bring up incase it was an issue with the array implementation itself. Thanks, James ------------------------------------------------------------------------ [2016-04-14 14:35:40] jhdxr@php.net "$this is removed from the array in the destructor" In fact, you did NOT removed $thif from the array. $this->things[] = null; add a new element into the array. You can use $this->things = null; or `unset($this->things); ------------------------------------------------------------------------ [2016-03-14 07:40:00] james dot harris at icecave dot com dot au Description: ------------ A memory leak occurs when array that contains a reference to $this is altered in the object's destructor. The leak does not occur if: * the array does not contain $this * the array is not altered in the destructor * $this is removed from the array in the destructor Affected PHP versions: https://3v4l.org/lHeRV This gist (https://gist.github.com/jmalloc/b88752e391d464609339) also contains the script to reproduce. Test script: --------------- class MemoryLeak { public function __construct() { $this->things[] = $this; } public function __destruct() { $this->things[] = null; } private $things = []; } ini_set('memory_limit', '10M'); for ($i = 0; $i < 100000; ++$i) { $obj = new MemoryLeak(); } echo "Done"; Expected result: ---------------- Done Actual result: -------------- Fatal error: Allowed memory size of 10485760 bytes exhausted (tried to allocate 20480 bytes) in /Users/james/<snip>/leak.php on line 30 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=71818&edit=1