Object.getOwnPropertyNames should be free of duplicates

BUG=41243
Review URL: http://codereview.chromium.org/2825026

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4958 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/v8natives.js

@@ -677,9 +677,17 @@ function ObjectGetOwnPropertyNames(obj) {
     }
   }
 
-  // Property names are expected to be strings.
-  for (var i = 0; i < propertyNames.length; ++i)
-    propertyNames[i] = ToString(propertyNames[i]);
+  // Property names are expected to be unique strings.
+  var propertySet = {};
+  var j = 0;
+  for (var i = 0; i < propertyNames.length; ++i) {
+    var name = ToString(propertyNames[i]);
+    if (name in propertySet)
+      continue;
+    propertySet[name] = true;
+    propertyNames[j++] = name;
+  }
+  propertyNames.length = j;
 
   return propertyNames;
 }

test/cctest/test-api.cc

@@ -5035,6 +5035,31 @@ THREADED_TEST(AccessControlGetOwnPropertyNames) {
 }
 
 
+static v8::Handle<v8::Array> NamedPropertyEnumerator(const AccessorInfo& info) {
+  v8::Handle<v8::Array> result = v8::Array::New(1);
+  result->Set(0, v8_str("x"));
+  return result;
+}
+
+
+THREADED_TEST(GetOwnPropertyNamesWithInterceptor) {
+  v8::HandleScope handle_scope;
+  v8::Handle<v8::ObjectTemplate> obj_template = v8::ObjectTemplate::New();
+
+  obj_template->Set(v8_str("x"), v8::Integer::New(42));
+  obj_template->SetNamedPropertyHandler(NULL, NULL, NULL, NULL,
+                                        NamedPropertyEnumerator);
+  
+  LocalContext context;
+  v8::Handle<v8::Object> global = context->Global();
+  global->Set(v8_str("object"), obj_template->NewInstance());
+
+  v8::Handle<Value> value =
+      CompileRun("Object.getOwnPropertyNames(object).join(',')");
+  CHECK_EQ(v8_str("x"), value);
+}
+
+
 static v8::Handle<Value> ConstTenGetter(Local<String> name,
                                         const AccessorInfo& info) {
   return v8_num(10);