slight fixups

Author: rawls238

graphql/core/.DS_Store

@@ -68,13 +68,9 @@ def enter(self, node, key, parent, path, ancestors):
             result = False
 
         if result is None and getattr(self.instance, 'visit_spread_fragments', False) and isinstance(node, FragmentSpread):
-            try:
-                fragment = self.instance.context.get_fragment(node.name.value)
-            except KeyError:
-                pass
-            else:
-                if fragment:
-                    visit(fragment, self)
+            fragment = self.instance.context.get_fragment(node.name.value)
+            if fragment:
+                visit(fragment, self)
 
         if result is False:
             self.type_info.leave(node)

graphql/core/validation/__init__.py

@@ -628,11 +628,11 @@ class VariablesInAllowedPosition(ValidationRule):
     def __init__(self, context):
         super(VariablesInAllowedPosition, self).__init__(context)
         self.var_def_map = {}
-        self.visited_fragment_names = {}
+        self.visited_fragment_names = set()
 
     def enter_OperationDefinition(self, *args):
         self.var_def_map = {}
-        self.visited_fragment_names = {}
+        self.visited_fragment_names = set()
 
     def enter_VariableDefinition(self, var_def_ast, *args):
         self.var_def_map[var_def_ast.variable.name.value] = var_def_ast
@@ -648,7 +648,7 @@ def enter_Variable(self, variable_ast, *args):
     def enter_FragmentSpread(self, spread_ast, *args):
         if spread_ast.name.value in self.visited_fragment_names:
             return False
-        self.visited_fragment_names[spread_ast.name.value] = True;
+        self.visited_fragment_names.add(spread_ast.name.value);
 
     @staticmethod
     def effective_type(var_type, var_def):