Bug #64195 [Opn->Nab]: clone object with circular reference cause segfault

Edit report at https://bugs.php.net/bug.php?id=64195&edit=1 ID: 64195 Updated by: johannes@php.net Reported by: vovan-ve at yandex dot ru Summary: clone object with circular reference cause segfault -Status: Open +Status: Not a bug Type: Bug Package: Class/Object related Operating System: linux PHP Version: 5.4.11 Block user comment: N Private report: N New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php Infinite recursion leads to a stack overflow (clone calls clone, calls clone, calls clone, ...) we have no good way to handle this. Previous Comments: ------------------------------------------------------------------------ [2013-02-12 11:33:20] vovan-ve at yandex dot ru Description: ------------ There are two objects of the same class. Both objects has a property. There are circular object reference: $a->prop === $b && $b->prop === $a. The class has a __clone() handler which clones object in that property. So, clonning such object cause segfault. Yes, described architecture is ugly, but this is just for test. Test code: ---- class A { public $prop; public function __clone() { $this->prop = clone $this->prop; } } // create two objects $a = new A(); $b = new A(); // create circular reference $b->prop = $a; $a->prop = $b; // see short dump with *RECURSION* marker print_r($a); // now make a problem $c = clone $a; // never will reach here print_r($c); ---- 5.5.0.a2, 5.4.11, 5.3.20 and 5.2.17 crashes with segfault. It is infinite recursion. Also Fatal Error can be emited about memory allocation when small memory_limit is set (1M for example). Unlimited recursion for a simple function cause a fatal error, so the bug always should cause the same fatal error. Test script: --------------- class A { public $prop; public function __clone() { $this->prop = clone $this->prop; } } $a = new A(); $b = new A(); $b->prop = $a; $a->prop = $b; print_r($a); $c = clone $a; print_r($c); Expected result: ---------------- A Object ( [prop] => A Object ( [prop] => A Object *RECURSION* ) ) Fatal error: Allowed memory size of ... bytes exhausted (tried to allocate ... bytes) Actual result: -------------- A Object ( [prop] => A Object ( [prop] => A Object *RECURSION* ) ) Segmentation fault (core dumped) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=64195&edit=1