Revert r73401 per Raymond Hettinger's request.

avassalotti · avassalotti · commit 7bd141b4340d · 2009-06-12T23:03:35.000Z
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.
diff --git a/Lib/collections.py b/Lib/collections.py
@@ -99,16 +99,14 @@ def __reversed__(self):
 
     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
@@ -795,9 +795,9 @@ def test_reduce_not_too_fat(self):
         # 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)])
