Restore compatibility with functions pickled with 0.4.0

cloudpickle/cloudpickle.py

@@ -943,7 +943,17 @@ def __reduce__(cls):
         return cls.__name__
 
 
-def _fill_function(func, globals, defaults, dict, module, closure_values):
+def _fill_function(*args):
+    if len(args) == 5:
+        # Backwards compat for cloudpickle v0.4.0, after which the `module`
+        # argument  was introduced
+        updated_args = args[:-1] + (None, args[-1],)
+        return _fill_function_internal(*updated_args)
+    else:
+        return _fill_function_internal(*args)
+
+
+def _fill_function_internal(func, globals, defaults, dict, module, closure_values):
     """ Fills in the rest of function data into the skeleton function object
         that were created via _make_skel_func().
     """

tests/cloudpickle_test.py

@@ -724,6 +724,33 @@ def test_builtin_type__new__(self):
         for t in list, tuple, set, frozenset, dict, object:
             self.assertTrue(pickle_depickle(t.__new__) is t.__new__)
 
+    @pytest.mark.skipif(sys.version_info >= (3, 0),
+                        reason="hardcoded pickle bytes for 2.7")
+    def test_function_pickle_compat_0_4_0(self):
+        # The result of `cloudpickle.dumps(lambda x: x)` in cloudpickle 0.4.0,
+        # Python 2.7
+        pickled = (b'\x80\x02ccloudpickle.cloudpickle\n_fill_function\nq\x00(c'
+            b'cloudpickle.cloudpickle\n_make_skel_func\nq\x01ccloudpickle.clou'
+            b'dpickle\n_builtin_type\nq\x02U\x08CodeTypeq\x03\x85q\x04Rq\x05(K'
+            b'\x01K\x01K\x01KCU\x04|\x00\x00Sq\x06N\x85q\x07)U\x01xq\x08\x85q'
+            b'\tU\x07<stdin>q\nU\x08<lambda>q\x0bK\x01U\x00q\x0c))tq\rRq\x0eJ'
+            b'\xff\xff\xff\xff}q\x0f\x87q\x10Rq\x11}q\x12N}q\x13NtR.')
+        self.assertEquals(42, cloudpickle.loads(pickled)(42))
+
+    @pytest.mark.skipif(sys.version_info >= (3, 0),
+                        reason="hardcoded pickle bytes for 2.7")
+    def test_function_pickle_compat_0_4_1(self):
+        # The result of `cloudpickle.dumps(lambda x: x)` in cloudpickle 0.4.1,
+        # Python 2.7
+        pickled = (b'\x80\x02ccloudpickle.cloudpickle\n_fill_function\nq\x00(c'
+            b'cloudpickle.cloudpickle\n_make_skel_func\nq\x01ccloudpickle.clou'
+            b'dpickle\n_builtin_type\nq\x02U\x08CodeTypeq\x03\x85q\x04Rq\x05(K'
+            b'\x01K\x01K\x01KCU\x04|\x00\x00Sq\x06N\x85q\x07)U\x01xq\x08\x85q'
+            b'\tU\x07<stdin>q\nU\x08<lambda>q\x0bK\x01U\x00q\x0c))tq\rRq\x0eJ'
+            b'\xff\xff\xff\xff}q\x0f\x87q\x10Rq\x11}q\x12N}q\x13U\x08__main__q'
+            b'\x14NtR.')
+        self.assertEquals(42, cloudpickle.loads(pickled)(42))
+
 
 if __name__ == '__main__':
     unittest.main()