Index: Zend/zend_compile.c
===================================================================
RCS file: /repository/ZendEngine2/zend_compile.c,v
retrieving revision 1.839
diff -u -p -r1.839 zend_compile.c
--- Zend/zend_compile.c	24 Aug 2008 17:01:21 -0000	1.839
+++ Zend/zend_compile.c	24 Aug 2008 18:16:43 -0000
@@ -2888,13 +2888,16 @@ ZEND_API void zend_do_inheritance(zend_c
 	}
 
 	ce->parent = parent_ce;
+	/* Transfer parent custom callbacks, if any */
+	if (!ce->serialize) {
+		ce->serialize = parent_ce->serialize;
+	}
+	if (!ce->unserialize) {
+		ce->unserialize = parent_ce->unserialize;
+	}
 	/* Inherit interfaces */
 	zend_do_inherit_interfaces(ce, parent_ce TSRMLS_CC);
 
-	/* Copy serialize/unserialize callbacks */
-	ce->serialize   = parent_ce->serialize;
-	ce->unserialize = parent_ce->unserialize;
-
 	/* Inherit properties */
 	zend_hash_merge(&ce->default_properties, &parent_ce->default_properties, (void (*)(void *)) zval_add_ref, NULL, sizeof(zval *), 0);
 	if (parent_ce->type != ce->type) {
Index: Zend/zend_interfaces.c
===================================================================
RCS file: /repository/ZendEngine2/zend_interfaces.c,v
retrieving revision 1.69
diff -u -p -r1.69 zend_interfaces.c
--- Zend/zend_interfaces.c	24 Aug 2008 17:01:22 -0000	1.69
+++ Zend/zend_interfaces.c	24 Aug 2008 18:16:43 -0000
@@ -474,13 +474,17 @@ ZEND_API int zend_user_unserialize(zval 
 /* {{{ zend_implement_serializable */
 static int zend_implement_serializable(zend_class_entry *interface, zend_class_entry *class_type TSRMLS_DC)
 {
-	if ((class_type->serialize   && class_type->serialize   != zend_user_serialize)
-	||  (class_type->unserialize && class_type->unserialize != zend_user_unserialize)
-	) {
+	if (class_type->parent 
+		&& (class_type->parent->serialize || class_type->parent->unserialize) 
+		&& !instanceof_function_ex(class_type->parent, zend_ce_serializable, 1 TSRMLS_CC)) {
 		return FAILURE;
 	}
-	class_type->serialize = zend_user_serialize;
-	class_type->unserialize = zend_user_unserialize;
+	if (!class_type->serialize) {
+		class_type->serialize = zend_user_serialize;
+	}
+	if (!class_type->unserialize) {
+		class_type->unserialize = zend_user_unserialize;
+	}
 	return SUCCESS;
 }
 /* }}}*/