bpo-40389: Improve repr of typing.Optional (#19714)

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Vlad Serebrennikov 2020-04-30 04:06:39 +03:00 committed by GitHub
parent b1e11c31c5
commit 138a9b9c2a
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4 changed files with 10 additions and 2 deletions

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@ -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

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@ -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]]')

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@ -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:

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@ -0,0 +1 @@
``repr()`` now returns ``typing.Optional[T]`` when called for ``typing.Union`` of two types, one of which is ``NoneType``.