From 206c521a1f980c1c422543f3a17fca619e9ec5ee Mon Sep 17 00:00:00 2001
From: "Christoph M. Becker" <cmbecker69@gmx.de>
Date: Sun, 12 Dec 2021 19:53:02 +0100
Subject: [PATCH] Fix GH-7757: Multi-inherited final constant causes fatal
 error

"Diamond" inheritance of final constants is supposed to be supported.

Closes GH-7767.
---
 NEWS                                           |  2 ++
 .../final_constants/final_const13.phpt         | 18 ++++++++++++++++++
 Zend/zend_inheritance.c                        |  2 +-
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 Zend/tests/constants/final_constants/final_const13.phpt

diff --git a/NEWS b/NEWS
index 28575db948d..c6ae9489f96 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,8 @@ PHP                                                                        NEWS
     on final or abstract interface methods). (ilutov)
   . Fixed bug #81585 (cached_chunks are not counted to real_size on shutdown).
     (cmb)
+  . Fixed bug GH-7757 (Multi-inherited final constant causes fatal error).
+    (cmb)
 
 - Hash:
   . Fixed bug GH-7759 (Incorrect return types for hash() and hash_hmac()).
diff --git a/Zend/tests/constants/final_constants/final_const13.phpt b/Zend/tests/constants/final_constants/final_const13.phpt
new file mode 100644
index 00000000000..5e19e8a2126
--- /dev/null
+++ b/Zend/tests/constants/final_constants/final_const13.phpt
@@ -0,0 +1,18 @@
+--TEST--
+Bug GH-7757 (Multi-inherited final constant causes fatal error)
+--FILE--
+<?php
+interface EntityInterface {
+    final public const TEST = 'this';
+}
+
+interface KeyInterface extends EntityInterface {
+}
+
+interface StringableInterface extends EntityInterface {
+}
+
+class SomeTestClass implements KeyInterface, StringableInterface {
+}
+?>
+--EXPECT--
diff --git a/Zend/zend_inheritance.c b/Zend/zend_inheritance.c
index 4903ef4b382..020c5e65539 100644
--- a/Zend/zend_inheritance.c
+++ b/Zend/zend_inheritance.c
@@ -1605,7 +1605,7 @@ static bool do_inherit_constant_check(
 	}
 
 	zend_class_constant *old_constant = Z_PTR_P(zv);
-	if ((ZEND_CLASS_CONST_FLAGS(parent_constant) & ZEND_ACC_FINAL)) {
+	if (parent_constant->ce != old_constant->ce && (ZEND_CLASS_CONST_FLAGS(parent_constant) & ZEND_ACC_FINAL)) {
 		zend_error_noreturn(E_COMPILE_ERROR, "%s::%s cannot override final constant %s::%s",
 			ZSTR_VAL(old_constant->ce->name), ZSTR_VAL(name),
 			ZSTR_VAL(parent_constant->ce->name), ZSTR_VAL(name)