Make interface constants overridable by default

Author: kocsismate

Zend/tests/constants/final_constants/final_const4.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Interface constants can be overridden directly
+--FILE--
+<?php
+
+interface I
+{
+    const X = 1;
+}
+
+class C implements I
+{
+    const X = 2;
+}
+
+?>
+--EXPECT--

Zend/tests/constants/final_constants/final_const5.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Final interface constants cannot be overridden directly
+--FILE--
+<?php
+
+interface I
+{
+    final public const X = 1;
+}
+
+class C implements I
+{
+    const X = 2;
+}
+
+?>
+--EXPECTF--
+Fatal error: C::X cannot override final constant I::X in %s on line %d

Zend/tests/constants/final_constants/final_const6.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Final interface constants can be inherited
+--FILE--
+<?php
+
+interface I
+{
+    final public const X = 1;
+}
+
+class C implements I
+{
+}
+
+?>
+--EXPECT--

Zend/tests/constants/final_constants/final_const7.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Interface constants can be overridden indirectly
+--FILE--
+<?php
+
+interface I
+{
+    const X = 1;
+}
+
+class C implements I {}
+
+class D extends C
+{
+    const X = 2;
+}
+
+?>
+--EXPECT--

Zend/tests/inter_01.phpt

@@ -4336,7 +4336,7 @@ ZEND_API zend_class_constant *zend_declare_class_constant_ex(zend_class_entry *c
 	zend_class_constant *c;
 
 	if (ce->ce_flags & ZEND_ACC_INTERFACE) {
-		if (access_type != ZEND_ACC_PUBLIC) {
+		if (!(access_type & ZEND_ACC_PUBLIC)) {
 			zend_error_noreturn(E_COMPILE_ERROR, "Access type for interface constant %s::%s must be public", ZSTR_VAL(ce->name), ZSTR_VAL(name));
 		}
 	}

Zend/zend_API.c

@@ -1503,7 +1503,14 @@ static bool do_inherit_constant_check(HashTable *child_constants_table, zend_cla
 
 	if (zv != NULL) {
 		old_constant = (zend_class_constant*)Z_PTR_P(zv);
-		if (old_constant->ce != parent_constant->ce) {
+
+		if ((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(iface->name), ZSTR_VAL(name)
+			);
+		}
+
+		if (old_constant->ce != parent_constant->ce && old_constant->ce->ce_flags & ZEND_ACC_INTERFACE) {
 			zend_error_noreturn(E_COMPILE_ERROR, "Cannot inherit previously-inherited or override constant %s from interface %s", ZSTR_VAL(name), ZSTR_VAL(iface->name));
 		}
 		return 0;