Bug #73348 [Ver->Nab]: A class can override a constant inherited from an indirect parent interface.

Edit report at https://bugs.php.net/bug.php?id=73348&edit=1 ID: 73348 Updated by: cmb@php.net Reported by: mkh117 at gmail dot com Summary: A class can override a constant inherited from an indirect parent interface. -Status: Verified +Status: Not a bug Type: Bug Package: Class/Object related Operating System: Ubuntu 16.04.1 PHP Version: 7.0.12 -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: Actually, this is not a bug, but rather the fact that constants defined in interfaces could not be overridden was. This is all resolved as of PHP 8.1.0[1] due to the introduction of final constants[2]. > […], so I'd love to get an idea of whether I need to break BC to > avoid my house burning down on a patch release. No worries. :) [1] <https://3v4l.org/c5dmY> [2] <https://wiki.php.net/rfc/final_class_const> Previous Comments: ------------------------------------------------------------------------ [2021-09-23 15:00:38] dktapps at pmmp dot io Is there any discussion on what to do about this problem? I just learned that a project of mine (with an API stable for 3 years) unintentionally exploited this bug, so I'd love to get an idea of whether I need to break BC to avoid my house burning down on a patch release. ------------------------------------------------------------------------ [2016-10-21 15:57:30] leigh@php.net Actually that might not be a bug, possibly designed to prevent: class B implements A, A {} ------------------------------------------------------------------------ [2016-10-21 15:42:29] leigh@php.net Related: interface A {} abstract class B implements A {} class C extends B implements A {} I would expect this to generate: "Class %s cannot implement previously implemented interface %s" Both this and the constant override issue are handled by zend_do_implement_interface which is not called for for grandchildren implementors ------------------------------------------------------------------------ [2016-10-19 15:17:45] cmb@php.net Confirmed: <https://3v4l.org/u4Y1q>. ------------------------------------------------------------------------ [2016-10-19 13:08:33] mkh117 at gmail dot com Description: ------------ When a class inherits a constant from an interface that is not a direct parent of the class, it can override its value without any errors thrown. Test script: --------------- <?php interface a { const con = 'Original value'; } abstract class b implements a { } class d extends b { const con='Overridden value'; } echo d::con; Expected result: ---------------- Fatal error: Cannot inherit previously-inherited constant con from interface a ... on line 11 Actual result: -------------- The script works and the interface constant is overridden. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=73348&edit=1