Bug #66237 [Opn->Nab]: Mutating __toString causes array_intersect to return empty

Edit report at https://bugs.php.net/bug.php?id=66237&edit=1 ID: 66237 Updated by: aharvey@php.net Reported by: simon at simon dot geek dot nz Summary: Mutating __toString causes array_intersect to return empty -Status: Open +Status: Not a bug Type: Bug Package: Unknown/Other Function PHP Version: 5.5Git-2013-12-04 (Git) 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 array_intersect() is documented as comparing the string form of each element — if that's unstable, then bad things may happen. Previous Comments: ------------------------------------------------------------------------ [2013-12-04 21:53:53] simon at simon dot geek dot nz Description: ------------ Hopefully the test script is self-explanatory. When running array_intersect on arrays that contains an object that mutates itself and the return value in its __toString() method, the result is an empty array even if there are literal values in the arrays that intersect. Test script: --------------- <?php class A { protected $i = 0; public function __toString() { $this->i++; return "$this->i"; } } $a = new A; $b = ['100', $a]; var_dump(array_intersect($b, $b)); Expected result: ---------------- array(1) { [0]=> string(3) "100" } Actual result: -------------- array(0) { } ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=66237&edit=1