Revert type hints support

CHANGES.md

@@ -1,6 +1,12 @@
 1.2.2
 =====
 
+- Revert the change introduced in
+ ([issue #276](https://github.com/cloudpipe/cloudpickle/pull/276))
+ attempting to pickle functions annotations for Python 3.4 to 3.6. It is not
+ possible to pickle complex typing constructs for those versions (see
+ [issue #193]( https://github.com/cloudpipe/cloudpickle/issues/193))
+
 - Fix a bug affecting bound classmethod saving on Python 2.
  ([issue #288](https://github.com/cloudpipe/cloudpickle/issues/288))
 

README.md

@@ -85,6 +85,25 @@ Running the tests
  PYTHONPATH='.:tests' py.test
 
 
+Note about function Annotations
+-------------------------------
+
+Note that because of design issues `Python`'s `typing` module, `cloudpickle`
+supports pickling type annotations of dynamic functions for `Python` 3.7 and
+later. On `Python` 3.4, 3.5 and 3.6, those type annotations will be dropped
+silently during pickling (example below):
+
+```python
+>>> import typing
+>>> import cloudpickle
+>>> def f(x: typing.Union[list, int]):
+... return x
+>>> f
+<function __main__.f(x:Union[list, int])>
+>>> cloudpickle.loads(cloudpickle.dumps(f)) # drops f's annotations
+<function __main__.f(x)>
+```
+
 History
 -------
 

cloudpickle/cloudpickle.py

@@ -747,7 +747,9 @@ def save_function_tuple(self, func):
  'doc': func.__doc__,
  '_cloudpickle_submodules': submodules
  }
- if hasattr(func, '__annotations__') and sys.version_info >= (3, 4):
+ if hasattr(func, '__annotations__') and sys.version_info >= (3, 7):
+ # Although annotations were added in Python3.4, It is not possible
+ # to properly pickle them until Python3.7. (See #193)
  state['annotations'] = func.__annotations__
  if hasattr(func, '__qualname__'):
  state['qualname'] = func.__qualname__

tests/cloudpickle_test.py

@@ -1621,9 +1621,9 @@ def g():
 
  self.assertEqual(f2.__doc__, f.__doc__)
 
- @unittest.skipIf(sys.version_info < (3, 4),
- """This syntax won't work on py2 and pickling annotations
- isn't supported for py34 and below.""")
+ @unittest.skipIf(sys.version_info < (3, 7),
+ "This syntax won't work on py2 and pickling annotations "
+"isn't supported for py37 and below.")
  def test_wraps_preserves_function_annotations(self):
  from functools import wraps
 
@@ -1640,6 +1640,16 @@ def g(x):
 
  self.assertEqual(f2.__annotations__, f.__annotations__)
 
+ @unittest.skipIf(sys.version_info < (3, 7),
+ """This syntax won't work on py2 and pickling annotations
+ isn't supported for py37 and below.""")
+ def test_type_hint(self):
+ # Try to pickle compound typing constructs. This would typically fail
+ # on Python < 3.7 (See #193)
+ import typing
+ t = typing.Union[list, int]
+ assert pickle_depickle(t) == t
+
  def test_instance_with_slots(self):
  for slots in [["registered_attribute"], "registered_attribute"]:
  class ClassWithSlots(object):