faster copy

Author: ekampf

graphql/execution/base.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 import sys
-import copy
 
 from ..error import GraphQLError
 from ..language import ast
@@ -324,7 +323,7 @@ def clone(self):
             operation=self.operation,
             variable_values=self.variable_values,
             context=self.context,
-            path=copy.copy(self.path)
+            path=self.path[:] if self.path else []
         )