Fix property hook backing value access in multi-level inheritance

Discovered by Niels when testing GH-17376.

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.4.6
 
+- Core:
+  . Fixed property hook backing value access in multi-level inheritance.
+    (ilutov)
 
 27 Feb 2025, PHP 8.4.5
 

Zend/tests/property_hooks/multi_level_inheritance.phpt

@@ -0,0 +1,70 @@
+--TEST--
+Property hooks with multi level inheritance
+--FILE--
+<?php
+
+class A {
+    public $prop = 1;
+}
+
+class B extends A {
+    public $prop = 2 { get => parent::$prop::get() * 2; }
+}
+
+class C extends B {
+    public $prop = 3;
+}
+
+function test(A $a) {
+    var_dump($a);
+    var_dump((array)$a);
+    var_dump(unserialize(serialize($a)));
+    var_dump(get_object_vars($a));
+    var_dump(json_decode(json_encode($a)));
+}
+
+test(new B);
+test(new C);
+
+?>
+--EXPECTF--
+object(B)#%d (1) {
+  ["prop"]=>
+  int(2)
+}
+array(1) {
+  ["prop"]=>
+  int(2)
+}
+object(B)#%d (1) {
+  ["prop"]=>
+  int(2)
+}
+array(1) {
+  ["prop"]=>
+  int(4)
+}
+object(stdClass)#%d (1) {
+  ["prop"]=>
+  int(4)
+}
+object(C)#%d (1) {
+  ["prop"]=>
+  int(3)
+}
+array(1) {
+  ["prop"]=>
+  int(3)
+}
+object(C)#%d (1) {
+  ["prop"]=>
+  int(3)
+}
+array(1) {
+  ["prop"]=>
+  int(6)
+}
+object(stdClass)#%d (1) {
+  ["prop"]=>
+  int(6)
+}

Zend/zend_inheritance.c

@@ -1436,7 +1436,7 @@ static void do_inherit_property(zend_property_info *parent_info, zend_string *ke
 		}
 		if (!(parent_info->flags & ZEND_ACC_PRIVATE)) {
 			if (!(parent_info->ce->ce_flags & ZEND_ACC_INTERFACE)) {
-				child_info->prototype = parent_info;
+				child_info->prototype = parent_info->prototype;
 			}
 
 			if (UNEXPECTED((parent_info->flags & ZEND_ACC_STATIC) != (child_info->flags & ZEND_ACC_STATIC))) {