From 138a9b9c2a394f30f222c23391f9515a7df9d809 Mon Sep 17 00:00:00 2001 From: Vlad Serebrennikov Date: Thu, 30 Apr 2020 04:06:39 +0300 Subject: bpo-40389: Improve repr of typing.Optional (#19714) --- Lib/test/test_dataclasses.py | 2 +- Lib/test/test_typing.py | 2 +- Lib/typing.py | 7 +++++++ Misc/NEWS.d/next/Library/2020-04-25-20-00-58.bpo-40389.FPA6f0.rst | 1 + 4 files changed, 10 insertions(+), 2 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2020-04-25-20-00-58.bpo-40389.FPA6f0.rst diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py index e8fe455..b20103b 100644 --- a/Lib/test/test_dataclasses.py +++ b/Lib/test/test_dataclasses.py @@ -2028,7 +2028,7 @@ class TestDocString(unittest.TestCase): class C: x: Union[int, type(None)] = None - self.assertDocStrEqual(C.__doc__, "C(x:Union[int, NoneType]=None)") + self.assertDocStrEqual(C.__doc__, "C(x:Optional[int]=None)") def test_docstring_list_field(self): @dataclass diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py index cab8de0..21bc7c8 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -1750,7 +1750,7 @@ class GenericTests(BaseTestCase): self.assertEqual(repr(Union[Tuple, Tuple[int]]).replace('typing.', ''), 'Union[Tuple, Tuple[int]]') self.assertEqual(repr(Callable[..., Optional[T]][int]).replace('typing.', ''), - 'Callable[..., Union[int, NoneType]]') + 'Callable[..., Optional[int]]') self.assertEqual(repr(Callable[[], List[T]][int]).replace('typing.', ''), 'Callable[[], List[int]]') diff --git a/Lib/typing.py b/Lib/typing.py index c829898..f3cd280 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -691,6 +691,13 @@ class _GenericAlias(_Final, _root=True): return _GenericAlias(self.__origin__, params, name=self._name, inst=self._inst) def __repr__(self): + if (self.__origin__ == Union and len(self.__args__) == 2 + and type(None) in self.__args__): + if self.__args__[0] is not type(None): + arg = self.__args__[0] + else: + arg = self.__args__[1] + return (f'typing.Optional[{_type_repr(arg)}]') if (self._name != 'Callable' or len(self.__args__) == 2 and self.__args__[0] is Ellipsis): if self._name: diff --git a/Misc/NEWS.d/next/Library/2020-04-25-20-00-58.bpo-40389.FPA6f0.rst b/Misc/NEWS.d/next/Library/2020-04-25-20-00-58.bpo-40389.FPA6f0.rst new file mode 100644 index 0000000..e7a60a8 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-04-25-20-00-58.bpo-40389.FPA6f0.rst @@ -0,0 +1 @@ +``repr()`` now returns ``typing.Optional[T]`` when called for ``typing.Union`` of two types, one of which is ``NoneType``. \ No newline at end of file -- cgit v0.12