Check enumerability of array indices correctly in propertyIsEnumerable.

src/runtime.cc

 // Copyright 2011 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 4686 matching lines @@
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_IsPropertyEnumerable) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
 
   CONVERT_CHECKED(JSObject, object, args[0]);
   CONVERT_CHECKED(String, key, args[1]);
 
   uint32_t index;
   if (key->AsArrayIndex(&index)) {
-    return isolate->heap()->ToBoolean(object->HasElement(index));
+    JSObject::LocalElementType type = object->HasLocalElement(index);
+    switch (type) {
+      case JSObject::UNDEFINED_ELEMENT:
+      case JSObject::STRING_CHARACTER_ELEMENT:
+        return isolate->heap()->false_value();
+      case JSObject::INTERCEPTED_ELEMENT:
+      case JSObject::FAST_ELEMENT:
+        return isolate->heap()->true_value();
+      case JSObject::DICTIONARY_ELEMENT: {
+        if (object->IsJSGlobalProxy()) {
+          Object* proto = object->GetPrototype();
+          if (proto->IsNull()) {
+            return isolate->heap()->false_value();
+          }
+          ASSERT(proto->IsJSGlobalObject());
+          object = JSObject::cast(proto);
+        }
+        FixedArray* elements = FixedArray::cast(object->elements());
+        NumberDictionary* dictionary = NULL;
+        if (elements->map() ==
+            isolate->heap()->non_strict_arguments_elements_map()) {
+          dictionary = NumberDictionary::cast(elements->get(1));
+        } else {
+          dictionary = NumberDictionary::cast(elements);
+        }
+        int entry = dictionary->FindEntry(index);
+        ASSERT(entry != NumberDictionary::kNotFound);
+        PropertyDetails details = dictionary->DetailsAt(entry);
+        return isolate->heap()->ToBoolean(!details.IsDontEnum());
+      }
+    }
   }
 
   PropertyAttributes att = object->GetLocalPropertyAttribute(key);
   return isolate->heap()->ToBoolean(att != ABSENT && (att & DONT_ENUM) == 0);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetPropertyNames) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
@@ skipping 8499 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags);
   }
 }
 
 
 } }  // namespace v8::internal