https://github.com/python/cpython/commit/b2ac70a62ad1be8e037ce45ccf5f1b753ea5e64b
commit: b2ac70a62ad1be8e037ce45ccf5f1b753ea5e64b
branch: main
author: Serhiy Storchaka <[email protected]>
committer: serhiy-storchaka <[email protected]>
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.
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