If using a frozen class with slots, add __getstate__ and __setstate__ to set the instance values. (GH-25786)
diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py
index 2fa0ae0..16ee4c7 100644
--- a/Lib/test/test_dataclasses.py
+++ b/Lib/test/test_dataclasses.py
@@ -2833,6 +2833,19 @@ class A:
self.assertFalse(hasattr(A, "__slots__"))
self.assertTrue(hasattr(B, "__slots__"))
+ # Can't be local to test_frozen_pickle.
+ @dataclass(frozen=True, slots=True)
+ class FrozenSlotsClass:
+ foo: str
+ bar: int
+
+ def test_frozen_pickle(self):
+ # bpo-43999
+
+ assert self.FrozenSlotsClass.__slots__ == ("foo", "bar")
+ p = pickle.dumps(self.FrozenSlotsClass("a", 1))
+ assert pickle.loads(p) == self.FrozenSlotsClass("a", 1)
+
class TestDescriptors(unittest.TestCase):
def test_set_name(self):