[Python-checkins] bpo-40398: Fix typing.get_args() for special generic aliases. (GH-19720)
Serhiy Storchaka
webhook-mailer at python.org
Mon Apr 27 03:27:30 EDT 2020
https://github.com/python/cpython/commit/6292be7adf247589bbf03524f8883cb4cb61f3e9
commit: 6292be7adf247589bbf03524f8883cb4cb61f3e9
branch: master
author: Serhiy Storchaka <storchaka at gmail.com>
committer: GitHub <noreply at github.com>
date: 2020-04-27T10:27:21+03:00
summary:
bpo-40398: Fix typing.get_args() for special generic aliases. (GH-19720)
files:
A Misc/NEWS.d/next/Library/2020-04-26-22-25-36.bpo-40398.OdXnR3.rst
M Lib/test/test_typing.py
M Lib/typing.py
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 46e0ea559ddb4..f191d3bb9e90c 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -3007,6 +3007,8 @@ class C(Generic[T]): pass
self.assertIs(get_origin(List[Tuple[T, T]][int]), list)
self.assertIs(get_origin(Annotated[T, 'thing']), Annotated)
self.assertIs(get_origin(List), list)
+ self.assertIs(get_origin(Tuple), tuple)
+ self.assertIs(get_origin(Callable), collections.abc.Callable)
self.assertIs(get_origin(list[int]), list)
self.assertIs(get_origin(list), None)
@@ -3024,13 +3026,16 @@ class C(Generic[T]): pass
(int, Tuple[str, int]))
self.assertEqual(get_args(typing.Dict[int, Tuple[T, T]][Optional[int]]),
(int, Tuple[Optional[int], Optional[int]]))
- self.assertEqual(get_args(Callable[[], T][int]), ([], int,))
+ self.assertEqual(get_args(Callable[[], T][int]), ([], int))
+ self.assertEqual(get_args(Callable[..., int]), (..., int))
self.assertEqual(get_args(Union[int, Callable[[Tuple[T, ...]], str]]),
(int, Callable[[Tuple[T, ...]], str]))
self.assertEqual(get_args(Tuple[int, ...]), (int, ...))
self.assertEqual(get_args(Tuple[()]), ((),))
self.assertEqual(get_args(Annotated[T, 'one', 2, ['three']]), (T, 'one', 2, ['three']))
- self.assertEqual(get_args(List), (typing.T,))
+ self.assertEqual(get_args(List), ())
+ self.assertEqual(get_args(Tuple), ())
+ self.assertEqual(get_args(Callable), ())
self.assertEqual(get_args(list[int]), (int,))
self.assertEqual(get_args(list), ())
diff --git a/Lib/typing.py b/Lib/typing.py
index 1aefcb8a8a27d..c82989861927d 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1420,11 +1420,13 @@ def get_args(tp):
"""
if isinstance(tp, _AnnotatedAlias):
return (tp.__origin__,) + tp.__metadata__
- if isinstance(tp, (_GenericAlias, GenericAlias)):
+ if isinstance(tp, _GenericAlias) and not tp._special:
res = tp.__args__
if tp.__origin__ is collections.abc.Callable and res[0] is not Ellipsis:
res = (list(res[:-1]), res[-1])
return res
+ if isinstance(tp, GenericAlias):
+ return tp.__args__
return ()
diff --git a/Misc/NEWS.d/next/Library/2020-04-26-22-25-36.bpo-40398.OdXnR3.rst b/Misc/NEWS.d/next/Library/2020-04-26-22-25-36.bpo-40398.OdXnR3.rst
new file mode 100644
index 0000000000000..a56da0c109592
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-04-26-22-25-36.bpo-40398.OdXnR3.rst
@@ -0,0 +1,2 @@
+:func:`typing.get_args` now always returns an empty tuple for special
+generic aliases.
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