Fix that custom attribute with function value cannot be cloned

fixes #10583

lib/base/dictionary.cpp

@@ -157,18 +157,18 @@ Dictionary::Ptr Dictionary::ShallowClone(void) const
 /**
  * Makes a deep clone of a dictionary
  * and its elements.
- * 
+ *
  * @returns a copy of the dictionary.
  */
 Object::Ptr Dictionary::Clone(void) const
 {
 	Dictionary::Ptr dict = new Dictionary();
-	
+
 	ObjectLock olock(this);
 	BOOST_FOREACH(const Dictionary::Pair& kv, m_Data) {
 		dict->Set(kv.first, kv.second.Clone());
 	}
-	
+
 	return dict;
 }
 

lib/base/function.cpp

@@ -39,3 +39,7 @@ bool Function::IsSideEffectFree(void) const
 	return m_SideEffectFree;
 }
 
+Object::Ptr Function::Clone(void) const
+{
+	return const_cast<Function *>(this);
+}

lib/base/function.hpp

@@ -49,6 +49,8 @@ public:
 
 	static Object::Ptr GetPrototype(void);
 
+	virtual Object::Ptr Clone(void) const override;
+
 private:
 	Callback m_Callback;
 	bool m_SideEffectFree;