Bug #74478 [NEW]: null coalescing operator failing with SplFixedArray

From: dariusz dot ruminski at gmail dot com Operating system: Windows PHP version: 7.1.4 Package: SPL related Bug Type: Bug Bug description:null coalescing operator failing with SplFixedArray 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 bug report at https://bugs.php.net/bug.php?id=74478&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=74478&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=74478&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=74478&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=74478&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=74478&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=74478&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=74478&r=needscript Try newer version: https://bugs.php.net/fix.php?id=74478&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=74478&r=support Expected behavior: https://bugs.php.net/fix.php?id=74478&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=74478&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=74478&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=74478&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74478&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=74478&r=dst IIS Stability: https://bugs.php.net/fix.php?id=74478&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=74478&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=74478&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=74478&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=74478&r=mysqlcfg