Revert r73401 per Raymond Hettinger's request.

The rational is the change might cause imcompatiblity problems with
PyYAML. In addition, Raymond wants to kept the different versions of
collections synchronized across Python versions.

2 files changed, 6 insertions, 8 deletions

diff --git a/Lib/collections.py b/Lib/collections.py
index 202b8b2..1e807af 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -99,16 +99,14 @@ class OrderedDict(dict, MutableMapping):
 
     def __reduce__(self):
         'Return state information for pickling'
-        dictitems = self.iteritems()
+        items = [[k, self[k]] for k in self]
         tmp = self.__map, self.__root
         del self.__map, self.__root
         inst_dict = vars(self).copy()
         self.__map, self.__root = tmp
-        # 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)
+        if inst_dict:
+            return (self.__class__, (items,), inst_dict)
+        return self.__class__, (items,)
 
     setdefault = MutableMapping.setdefault
     update = MutableMapping.update
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index b108f95..1c49876 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -795,9 +795,9 @@ class TestOrderedDict(unittest.TestCase):
         # 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.assertGreaterEqual(len(od.__reduce__()), 2)
-        self.assertLessEqual(len(od.__reduce__()), 5)
+        self.assertEqual(len(od.__reduce__()), 3)
 
     def test_repr(self):
         od = OrderedDict([('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)])