https://github.com/python/cpython/commit/b2ac70a62ad1be8e037ce45ccf5f1b753ea... commit: b2ac70a62ad1be8e037ce45ccf5f1b753ea5e64b branch: main author: Serhiy Storchaka <storchaka@gmail.com> committer: serhiy-storchaka <storchaka@gmail.com> date: 2024-12-31T10:02:58+02:00 summary: gh-88834: Unify the instance check for typing.Union and types.UnionType (GH-128363) Union now uses the instance checks against its parameters instead of the subclass checks. files: A Misc/NEWS.d/next/Library/2024-12-30-20-48-28.gh-issue-88834.RIvgwc.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 aa42beca5f9256..ef3cfc9517085e 100644 --- a/Lib/test/test_typing.py +++ b/Lib/test/test_typing.py @@ -122,7 +122,7 @@ class Sub(Any): pass def test_errors(self): with self.assertRaises(TypeError): - issubclass(42, Any) + isinstance(42, Any) with self.assertRaises(TypeError): Any[int] # Any is not a generic type. @@ -137,6 +137,9 @@ class Something: pass class MockSomething(Something, Mock): pass self.assertTrue(issubclass(MockSomething, Any)) + self.assertTrue(issubclass(MockSomething, MockSomething)) + self.assertTrue(issubclass(MockSomething, Something)) + self.assertTrue(issubclass(MockSomething, Mock)) ms = MockSomething() self.assertIsInstance(ms, MockSomething) self.assertIsInstance(ms, Something) @@ -2010,13 +2013,81 @@ def test_basics(self): u = Union[int, float] self.assertNotEqual(u, Union) - def test_subclass_error(self): + def test_union_isinstance(self): + self.assertTrue(isinstance(42, Union[int, str])) + self.assertTrue(isinstance('abc', Union[int, str])) + self.assertFalse(isinstance(3.14, Union[int, str])) + self.assertTrue(isinstance(42, Union[int, list[int]])) + self.assertTrue(isinstance(42, Union[int, Any])) + + def test_union_isinstance_type_error(self): + with self.assertRaises(TypeError): + isinstance(42, Union[str, list[int]]) + with self.assertRaises(TypeError): + isinstance(42, Union[list[int], int]) + with self.assertRaises(TypeError): + isinstance(42, Union[list[int], str]) + with self.assertRaises(TypeError): + isinstance(42, Union[str, Any]) + with self.assertRaises(TypeError): + isinstance(42, Union[Any, int]) + with self.assertRaises(TypeError): + isinstance(42, Union[Any, str]) + + def test_optional_isinstance(self): + self.assertTrue(isinstance(42, Optional[int])) + self.assertTrue(isinstance(None, Optional[int])) + self.assertFalse(isinstance('abc', Optional[int])) + + def test_optional_isinstance_type_error(self): + with self.assertRaises(TypeError): + isinstance(42, Optional[list[int]]) + with self.assertRaises(TypeError): + isinstance(None, Optional[list[int]]) + with self.assertRaises(TypeError): + isinstance(42, Optional[Any]) + with self.assertRaises(TypeError): + isinstance(None, Optional[Any]) + + def test_union_issubclass(self): + self.assertTrue(issubclass(int, Union[int, str])) + self.assertTrue(issubclass(str, Union[int, str])) + self.assertFalse(issubclass(float, Union[int, str])) + self.assertTrue(issubclass(int, Union[int, list[int]])) + self.assertTrue(issubclass(int, Union[int, Any])) + self.assertFalse(issubclass(int, Union[str, Any])) + self.assertTrue(issubclass(int, Union[Any, int])) + self.assertFalse(issubclass(int, Union[Any, str])) + + def test_union_issubclass_type_error(self): with self.assertRaises(TypeError): issubclass(int, Union) with self.assertRaises(TypeError): issubclass(Union, int) with self.assertRaises(TypeError): issubclass(Union[int, str], int) + with self.assertRaises(TypeError): + issubclass(int, Union[str, list[int]]) + with self.assertRaises(TypeError): + issubclass(int, Union[list[int], int]) + with self.assertRaises(TypeError): + issubclass(int, Union[list[int], str]) + + def test_optional_issubclass(self): + self.assertTrue(issubclass(int, Optional[int])) + self.assertTrue(issubclass(type(None), Optional[int])) + self.assertFalse(issubclass(str, Optional[int])) + self.assertTrue(issubclass(Any, Optional[Any])) + self.assertTrue(issubclass(type(None), Optional[Any])) + self.assertFalse(issubclass(int, Optional[Any])) + + def test_optional_issubclass_type_error(self): + with self.assertRaises(TypeError): + issubclass(list[int], Optional[list[int]]) + with self.assertRaises(TypeError): + issubclass(type(None), Optional[list[int]]) + with self.assertRaises(TypeError): + issubclass(int, Optional[list[int]]) def test_union_any(self): u = Union[Any] diff --git a/Lib/typing.py b/Lib/typing.py index 5f3aacd877221c..e69b485422cbd2 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1733,12 +1733,16 @@ def __repr__(self): return super().__repr__() def __instancecheck__(self, obj): - return self.__subclasscheck__(type(obj)) + for arg in self.__args__: + if isinstance(obj, arg): + return True + return False def __subclasscheck__(self, cls): for arg in self.__args__: if issubclass(cls, arg): return True + return False def __reduce__(self): func, (origin, args) = super().__reduce__() diff --git a/Misc/NEWS.d/next/Library/2024-12-30-20-48-28.gh-issue-88834.RIvgwc.rst b/Misc/NEWS.d/next/Library/2024-12-30-20-48-28.gh-issue-88834.RIvgwc.rst new file mode 100644 index 00000000000000..ca43f914880ba3 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-12-30-20-48-28.gh-issue-88834.RIvgwc.rst @@ -0,0 +1,3 @@ +Unify the instance check for :class:`typing.Union` and +:class:`types.UnionType`: :class:`!Union` now uses the instance checks +against its parameters instead of the subclass checks.