Make pickling of OrderedDict instances more efficient.
diff --git a/Lib/collections.py b/Lib/collections.py
index 1e807af..202b8b2 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -99,14 +99,16 @@
def __reduce__(self):
'Return state information for pickling'
- items = [[k, self[k]] for k in self]
+ dictitems = self.iteritems()
tmp = self.__map, self.__root
del self.__map, self.__root
inst_dict = vars(self).copy()
self.__map, self.__root = tmp
- if inst_dict:
- return (self.__class__, (items,), inst_dict)
- return self.__class__, (items,)
+ # Set the state item to None when the dictionary is empty. This saves
+ # about 2 opcodes when the object is pickled.
+ if not inst_dict:
+ inst_dict = None
+ return (self.__class__, (), inst_dict, None, dictitems)
setdefault = MutableMapping.setdefault
update = MutableMapping.update
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 1c49876..b108f95 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -795,9 +795,9 @@
# do not save instance dictionary if not needed
pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)]
od = OrderedDict(pairs)
- self.assertEqual(len(od.__reduce__()), 2)
od.x = 10
- self.assertEqual(len(od.__reduce__()), 3)
+ self.assertGreaterEqual(len(od.__reduce__()), 2)
+ self.assertLessEqual(len(od.__reduce__()), 5)
def test_repr(self):
od = OrderedDict([('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)])