ReturnValue::Set needs to check for empty handles

include/v8.h

 // Copyright 2012 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 5647 matching lines @@
 }
 
 
 template<typename T>
 ReturnValue<T>::ReturnValue(internal::Object** slot) : value_(slot) {}
 
 template<typename T>
 template<typename S>
 void ReturnValue<T>::Set(const Persistent<S>& handle) {
   TYPE_CHECK(T, S);
-  *value_ = *reinterpret_cast<internal::Object**>(*handle);
+  if (V8_UNLIKELY(handle.IsEmpty())) {
+    SetUndefined();
+  } else {
+    *value_ = *reinterpret_cast<internal::Object**>(*handle);
+  }
 }
 
 template<typename T>
 template<typename S>
 void ReturnValue<T>::Set(const Handle<S> handle) {
   TYPE_CHECK(T, S);
-  *value_ = *reinterpret_cast<internal::Object**>(*handle);
+  if (V8_UNLIKELY(handle.IsEmpty())) {
+    SetUndefined();
+  } else {
+    *value_ = *reinterpret_cast<internal::Object**>(*handle);
+  }
 }
 
 template<typename T>
 void ReturnValue<T>::Set(double i) {
   Set(Number::New(GetIsolate(), i));
 }
 
 template<typename T>
 void ReturnValue<T>::Set(int32_t i) {
   typedef internal::Internals I;
@@ skipping 617 matching lines @@
 
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_