Compatibility: expose cloudpickle.CloudPickler also as cloudpickle.Pickler (#392)

* Alias cloudpickle.CloudPickler as cloudpickle.Pickler

* Update tests/cloudpickle_test.py

Co-authored-by: Pierre Glaser <[email protected]>

* changelog

* Update CHANGES.md

* Update CHANGES.md

* Update cloudpickle/__init__.py

Co-authored-by: Pierre Glaser <[email protected]>

Author: twoertwein

CHANGES.md

@@ -1,6 +1,12 @@
 1.5.1 (in development)
 ======================
 
+- `cloudpickle`'s pickle.Pickler subclass (currently defined as
+  `cloudpickle.cloudpickle_fast.CloudPickler`) can and should now be accessed
+  as `cloudpickle.Pickler`. This is the only officially supported way of
+  accessing it. 
+  ([issue #366](https://github.com/cloudpipe/cloudpickle/issues/366))
+
 
 1.5.0
 =====

cloudpickle/__init__.py

@@ -4,4 +4,8 @@
 from cloudpickle.cloudpickle import *  # noqa
 from cloudpickle.cloudpickle_fast import CloudPickler, dumps, dump  # noqa
 
+# Conform to the convention used by python serialization libraries, which
+# expose their Pickler subclass at top-level under the  "Pickler" name.
+Pickler = CloudPickler
+
 __version__ = '1.5.1dev0'

tests/cloudpickle_test.py

@@ -2342,5 +2342,12 @@ class C(typing.Generic[T]):
     return types_to_test
 
 
+def test_module_level_pickler():
+    # #366: cloudpickle should expose its pickle.Pickler subclass as
+    # cloudpickle.Pickler
+    assert hasattr(cloudpickle, "Pickler")
+    assert cloudpickle.Pickler is cloudpickle.CloudPickler
+
+
 if __name__ == '__main__':
     unittest.main()