Repository navigation
dataclasses: frozen dataclasses with slots' __setattr__ and __delattr__ does not work. #105936
Description
Bug report
The check in frozen dataclasses' __setattr__ and __delattr__ does not work when slots=True:
@dataclass(frozen=True, slots=True)
class C:
i: int
C(10).j = 5
crashes with
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<string>", line 5, in __setattr__
TypeError: super(type, obj): obj must be an instance or subtype of type
instead of raising a FrozenInstanceError.
Likewise,
@dataclass(frozen=True, slots=True)
class C:
i: int
class D(C):
pass
D(10).j = 5
crashes with the same error instead of working.
Linked PRs
- gh-105936: Fix frozen dataclasses with slots'
__setattr__and__delattr_#105937 - gh-105936: Properly update closure cells for
__setattr__and__delattr__in frozen dataclasses with slots #144021 - [3.14] gh-105936: Properly update closure cells for
__setattr__and__delattr__in frozen dataclasses with slots (GH-144021) #148469 - [3.13] gh-105936: Properly update closure cells for __setattr__ and __delattr__ in frozen dataclasses with slots (GH-144021) #148476
Activity
gh-105936: Properly update closure cells for `__setattr__` and `__del…
pythongh-105936: Properly update closure cells for `__setattr__` and …
pythongh-105936: Properly update closure cells for `__setattr__` and …
[3.14] gh-105936: Properly update closure cells for `__setattr__` and…
[3.13] pythongh-105936: Properly update closure cells for `__setattr_…
gpshead commentedon Apr 13, 2026
A 3.13 is up as a Draft PR because it requires more changes and backporting pieces of some other stuff that is already in 3.14 in order for it to work.
Revert "pythongh-105936: Properly update closure cells for `__setattr…
pythongh-105936: Properly update closure cells for `__setattr__` and …
[3.13] gh-105936: Properly update closure cells for __setattr__ and _…
gpshead commentedon Apr 26, 2026
all merged. thanks for the report, contributions and reviews.