diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index 7c3285cf440a39..82b08fc017884f 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -1189,6 +1189,9 @@ def _add_slots(cls, is_frozen, weakref_slot): # Remove __dict__ itself. cls_dict.pop('__dict__', None) + # Clear existing `__weakref__` descriptor, it belongs to a previous type: + cls_dict.pop('__weakref__', None) # gh-102069 + # And finally create the class. qualname = getattr(cls, '__qualname__', None) cls = type(cls)(cls.__name__, cls.__bases__, cls_dict) diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py index 46d4e0fedad2f2..46f33043c27071 100644 --- a/Lib/test/test_dataclasses.py +++ b/Lib/test/test_dataclasses.py @@ -3175,6 +3175,8 @@ class A: with self.assertRaisesRegex(TypeError, "cannot create weak reference"): weakref.ref(a) + with self.assertRaises(AttributeError): + a.__weakref__ def test_slots_weakref(self): @dataclass(slots=True, weakref_slot=True) @@ -3183,7 +3185,9 @@ class A: self.assertIn("__weakref__", A.__slots__) a = A(1) - weakref.ref(a) + a_ref = weakref.ref(a) + + self.assertIs(a.__weakref__, a_ref) def test_slots_weakref_base_str(self): class Base: @@ -3249,7 +3253,8 @@ class A(Base): self.assertIn("__weakref__", Base.__slots__) self.assertNotIn("__weakref__", A.__slots__) a = A(1) - weakref.ref(a) + a_ref = weakref.ref(a) + self.assertIs(a.__weakref__, a_ref) def test_weakref_slot_subclass_no_weakref_slot(self): @dataclass(slots=True, weakref_slot=True) @@ -3265,7 +3270,8 @@ class A(Base): self.assertIn("__weakref__", Base.__slots__) self.assertNotIn("__weakref__", A.__slots__) a = A(1) - weakref.ref(a) + a_ref = weakref.ref(a) + self.assertIs(a.__weakref__, a_ref) def test_weakref_slot_normal_base_weakref_slot(self): class Base: @@ -3280,7 +3286,8 @@ class A(Base): self.assertIn("__weakref__", Base.__slots__) self.assertNotIn("__weakref__", A.__slots__) a = A(1) - weakref.ref(a) + a_ref = weakref.ref(a) + self.assertIs(a.__weakref__, a_ref) class TestDescriptors(unittest.TestCase): diff --git a/Misc/NEWS.d/next/Library/2023-02-20-16-47-56.gh-issue-102069.FS7f1j.rst b/Misc/NEWS.d/next/Library/2023-02-20-16-47-56.gh-issue-102069.FS7f1j.rst new file mode 100644 index 00000000000000..04c87e515cca93 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-02-20-16-47-56.gh-issue-102069.FS7f1j.rst @@ -0,0 +1 @@ +Fix ``__weakref__`` descriptor generation for custom dataclasses.