Make sure that post-interceptor property getter doesn't assume name lookup is...

src/objects.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6152 matching lines @@
   return InterceptorInfo::cast(result);
 }
 
 
 Object* JSObject::GetPropertyPostInterceptor(JSObject* receiver,
                                              String* name,
                                              PropertyAttributes* attributes) {
   // Check local property in holder, ignore interceptor.
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
-  if (result.IsValid()) return GetProperty(receiver, &result, name, attributes);
+  if (result.IsValid()) {
+    Object* p = GetProperty(receiver, &result, name, attributes);
+    // Successful name lookup doesn't mean the value is there, because the

[Mads Ager (chromium), 2010/02/18 08:29:30]

There is something fishy going on here.  The result.IsValid() check should make
sure that there actually is a property on the object.

+    // name could've been introduced by the interceptor. Only return property
+    // if it's not absent.
+    if (*attributes != ABSENT) return p;
+  }
   // Continue searching via the prototype chain.
   Object* pt = GetPrototype();
   *attributes = ABSENT;
   if (pt == Heap::null_value()) return Heap::undefined_value();
   return pt->GetPropertyWithReceiver(receiver, name, attributes);
 }
 
 
 Object* JSObject::GetLocalPropertyPostInterceptor(
     JSObject* receiver,
@@ skipping 2116 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal