Bug #72119 [Nab]: Interface declaration compatibility regression with default values

Edit report at https://bugs.php.net/bug.php?id=72119&edit=1 ID: 72119 Updated by: dmitry@php.net Reported by: ben dot davies at gmail dot com Summary: Interface declaration compatibility regression with default values Status: Not a bug Type: Bug Package: PHP Language Specification PHP Version: 7.0.6 Assigned To: levim Block user comment: N Private report: N New Comment: The original problem was introduced by attempt to fix #71428 (that expects exactly the opposite behavior) in commit ee9a78a033696ff9546fb1dbfecd28f20477b511 Previous Comments: ------------------------------------------------------------------------ [2016-04-28 15:26:30] ben dot davies at gmail dot com Hi both, No doubt you are both correct, but this appears to be a BC break. This works in every version of php up to 7.0.6. https://3v4l.org/VhEtd Thanks ------------------------------------------------------------------------ [2016-04-28 15:23:48] levim@php.net I have confirmed that this is not a bug. The reason is that in the interface you are permitted to pass null: <?php $Foo->bar(null); ?> However, in the implementing class Hello it would not be permitted. Everything permitted in the parent must also be permitted in the child, thus it is not a bug. ------------------------------------------------------------------------ [2016-04-28 15:22:29] bwoebi@php.net This is not a bug; your code is a LSP violation which had been fixed in bug #71428. In the concrete example, the Foo::bar() function can be passed null, but Hello::bar() cannot. [This is something we try to fix with nullable parameters/null unions in 7.1.] ------------------------------------------------------------------------ [2016-04-28 15:18:48] levim@php.net This was changed in commit e9d65160 by Dmitry. It appears to be a fix for a different bug (71978). ------------------------------------------------------------------------ [2016-04-28 11:33:37] ben dot davies at gmail dot com Description: ------------ I wanted to raise this against 7.0.6, but it was not available in the list above, despite being released? There seems to be a regression in interface method declaration compatibility checking. The below test script only fails on 7.0.6. It also only fails if the $baz is type hinted as array. Test script: --------------- <?php interface Foo { public function bar(array $baz = null); } class Hello implements Foo { public function bar(array $baz = []) { } } Expected result: ---------------- N/A Actual result: -------------- Fatal error: Declaration of Hello::bar(array $baz = Array) must be compatible with Foo::bar(array $baz = NULL) in /in/VhEtd on line 7 Process exited with code 255. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=72119&edit=1