Description

avboag

opened on Jun 20, 2023

Issue body actions

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

Reacted by Abraham Murciano and Jaden Chuah

Activity

1. avboag

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jun 20, 2023
2. iritkatriel

   added

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   on Nov 26, 2023
3. gpshead

   added a commit that references this issue on Apr 12, 2026

   gh-105936: Properly update closure cells for `__setattr__` and `__del…

   8a398bf
4. miss-islington

   added a commit that references this issue on Apr 12, 2026

   pythongh-105936: Properly update closure cells for `__setattr__` and …

   3fcd711
5. gpshead

   added 3 commits that reference this issue on Apr 12, 2026

   pythongh-105936: Properly update closure cells for `__setattr__` and …

   6645d06

   [3.14] gh-105936: Properly update closure cells for `__setattr__` and…

   942d302

   [3.13] pythongh-105936: Properly update closure cells for `__setattr_…

   aa1e00f
6. gpshead commented on Apr 13, 2026

   

   gpshead

   on Apr 13, 2026

   Member

   More actions

   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.
7. prakashsellathurai

   added a commit that references this issue on Apr 13, 2026

   Revert "pythongh-105936: Properly update closure cells for `__setattr…

   cdcefcb
8. ljfp

   added a commit that references this issue on Apr 25, 2026

   pythongh-105936: Properly update closure cells for `__setattr__` and …

   187221c
9. gpshead

   added a commit that references this issue on Apr 26, 2026

   [3.13] gh-105936: Properly update closure cells for __setattr__ and _…

   9651429
10. gpshead

    self-assigned this

    on Apr 26, 2026
11. gpshead commented on Apr 26, 2026

    

    gpshead

    on Apr 26, 2026

    Member

    More actions

    all merged. thanks for the report, contributions and reviews.
12. gpshead

    closed this as completedon Apr 26, 2026

Issue actions