bpo-42740: Support PEP 604, 612 for typing.py get_args and get_origin (GH-23942)

Author: Fidget-Spinner

Lib/test/test_typing.py

@@ -3021,6 +3021,7 @@ class C(Generic[T]): pass
         self.assertIs(get_origin(Callable), collections.abc.Callable)
         self.assertIs(get_origin(list[int]), list)
         self.assertIs(get_origin(list), None)
+        self.assertIs(get_origin(list | str), types.Union)
 
     def test_get_args(self):
         T = TypeVar('T')
@@ -3053,6 +3054,11 @@ class C(Generic[T]): pass
         self.assertEqual(get_args(collections.abc.Callable[[], str]), ([], str))
         self.assertEqual(get_args(collections.abc.Callable[[int], str]),
                          get_args(Callable[[int], str]))
+        P = ParamSpec('P')
+        self.assertEqual(get_args(Callable[P, int]), (P, int))
+        self.assertEqual(get_args(Callable[Concatenate[int, P], int]),
+                         (Concatenate[int, P], int))
+        self.assertEqual(get_args(list | str), (list, str))
 
 
 class CollectionsAbcTests(BaseTestCase):

Lib/typing.py

@@ -1668,6 +1668,8 @@ def get_origin(tp):
         return tp.__origin__
     if tp is Generic:
         return Generic
+    if isinstance(tp, types.Union):
+        return types.Union
     return None
 
 
@@ -1686,9 +1688,13 @@ def get_args(tp):
         return (tp.__origin__,) + tp.__metadata__
     if isinstance(tp, (_GenericAlias, GenericAlias)):
         res = tp.__args__
-        if tp.__origin__ is collections.abc.Callable and res[0] is not Ellipsis:
+        if (tp.__origin__ is collections.abc.Callable
+                and not (res[0] is Ellipsis
+                         or isinstance(res[0], (ParamSpec, _ConcatenateGenericAlias)))):
             res = (list(res[:-1]), res[-1])
         return res
+    if isinstance(tp, types.Union):
+        return tp.__args__
     return ()
 
 

Misc/NEWS.d/next/Library/2020-12-25-23-23-11.bpo-42740.F0rQ_E.rst

@@ -0,0 +1,2 @@
+:func:`typing.get_args` and :func:`typing.get_origin` now support :pep:`604`
+union types and :pep:`612` additions to ``Callable``.