Bug #74072 [Com]: Memory leaks with setter causing out of memory

Edit report at https://bugs.php.net/bug.php?id=74072&edit=1 ID: 74072 Comment by: ealexs at gmail dot com Reported by: ealexs at gmail dot com Summary: Memory leaks with setter causing out of memory Status: Duplicate Type: Bug Package: Reproducible crash Operating System: Debian 8 PHP Version: 7.0.15 Block user comment: N Private report: N New Comment: Thank you very much all your points were useful. I think this should be added to the php docs as "Caution": "A magic accessor should not trigger a magic accessor on a different property name on the same object. $a->__get('x') -> $a->__set('x') is fine. $a->__get('x') -> $b->__get('y') is fine. $a->__get('x') -> $a->__get('y') may still lead to unbounded memory growth, if this is done for many distinct property names." > also add $a->__set('x') -> $a->__set('y') - unbounded memory > growth Suggested pages: http://php.net/manual/en/language.oop5.magic.php http://php.net/manual/en/language.oop5.overloading.php Previous Comments: ------------------------------------------------------------------------ [2017-02-16 12:57:24] nikic@php.net On the limitations, quoting from the other bug report: > A magic accessor should not trigger a magic accessor on a different property name on the same > object. $a->__get('x') -> $a->__set('x') is fine. > $a->__get('x') -> $b->__get('y') is fine. $a->__get('x') > -> $a->__get('y') may still lead to unbounded memory growth, if this is done for > many distinct property names. It is not possible to apply this change to PHP 7.0. As to the jumping memory usage between cycles, this is an artifact of passing "true" to memory_get_usage(). If you do so, you will see internal details of the allocator. In this case, what you observe is that when the memory limit is reached, an allocator GC is triggered, which may release chunks, thus reducing memory usage below the previous value. Generally, I'd recommend calling memory_get_usage() without argument, as the values become much harder to interpret otherwise. ------------------------------------------------------------------------ [2017-02-16 12:30:51] ealexs at gmail dot com @torben - less memory usage without XDEBUG, reduce memory or increase the cycles. @nikic Will the fix be applied for PHP 7.0.* also ? Can you explain a bit the limitations of the fix ? Why is the memory usage random between the cycles random ? (this worries me a bit) ------------------------------------------------------------------------ [2017-02-16 11:35:27] nikic@php.net Duplicate of bug #65340. ------------------------------------------------------------------------ [2017-02-16 11:22:55] torben at dannhauer dot info I can reproduce this bug with the below test script. I have a error in a production server which seems to be the same but I'm not sure. On my side, your testscript also fails with xdebug modul loaded, however my production error does disappear with Xdebug module loaded. ------------------------------------------------------------------------ [2017-02-16 07:53:24] ealexs at gmail dot com updated the "Package" ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=74072 -- Edit this bug report at https://bugs.php.net/bug.php?id=74072&edit=1