Bug #74478 [Opn->Asn]: null coalescing operator failing with SplFixedArray

Edit report at https://bugs.php.net/bug.php?id=74478&edit=1 ID: 74478 Updated by: jhdxr@php.net Reported by: dariusz dot ruminski at gmail dot com Summary: null coalescing operator failing with SplFixedArray -Status: Open +Status: Assigned Type: Bug Package: SPL related Operating System: Windows PHP Version: 7.1.4 Block user comment: N Private report: N Previous Comments: ------------------------------------------------------------------------ [2017-04-20 12:00:27] dariusz dot ruminski at gmail dot com https://3v4l.org/BudKa ------------------------------------------------------------------------ [2017-04-20 11:56:43] dariusz dot ruminski at gmail dot com Description: ------------ When I use null coalescing operator on a class implementing SplFixedArray then offsetExists is not called, but offsetGet is called instead (which may trigger some error). It should be equivalent to ternary operator with isset. This is similar to https://bugs.php.net/bug.php?id=71731 (here - SplFixedArray, there - ArrayAccess). https://3v4l.org/#v714 Test script: --------------- <?php $arrayData = new class implements \ArrayAccess { public function offsetExists($offset) { echo "offsetExists\n"; } public function offsetGet($offset) { echo "offsetGet\n"; } public function offsetSet($offset, $value) { } public function offsetUnset($offset) { } }; echo "arrayData - isset:\n"; isset($arrayData['foo']) ? NULL : NULL; echo "arrayData - null coalescing operator:\n"; $arrayData['foo'] ?? NULL; $fixedData = new class extends \SplFixedArray { public function offsetExists($offset) { echo "offsetExists\n"; } public function offsetGet($offset) { echo "offsetGet\n"; } public function offsetSet($offset, $value) { } public function offsetUnset($offset) { } }; echo "fixedData - isset:\n"; isset($fixedData['foo']) ? NULL : NULL; echo "fixedData - null coalescing operator:\n"; $fixedData['foo'] ?? NULL; Expected result: ---------------- arrayData - isset: offsetExists arrayData - null coalescing operator: offsetExists fixedData - isset: offsetExists fixedData - null coalescing operator: offsetExists Actual result: -------------- arrayData - isset: offsetExists arrayData - null coalescing operator: offsetExists fixedData - isset: offsetExists fixedData - null coalescing operator: offsetGet ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74478&edit=1