3.11.1 Regression: namedtuple Enum values are cast to tuple #100098

Zannick · 2022-12-08T03:21:12Z

Bug report

Between 3.11.0 and 3.11.1, Enums whose values are namedtuple objects have their values converted to tuple, which drops the field names we expect to be able to use, causing AttributeErrors. Test cases below create a namedtuple and an enum whose values are instances of that tuple. In the 3.11.1 case, referencing the enum value like NTEnum.NONE.value produces a tuple and not a namedtuple. In both cases, copy.copy preserves the namedtuple type.

It is not clear whether any item in the changelog or release notes references this change, nor could I quickly tell whether this was related to changes to address #93910.

Python 3.11.0 (main, Oct 24 2022, 18:26:48) [MSC v.1933 64 bit (AMD64)] on win32

>>> from enum import Enum
>>> from collections import namedtuple
>>> TTuple = namedtuple('TTuple', 'id a blist')
>>> class NTEnum(Enum):
...     NONE = TTuple(0, 0, [])
...     A = TTuple(1, 2, [4])
...     B = TTuple(2, 4, [0, 1, 2])
... 
...     
>>> NTEnum.NONE
<NTEnum.NONE: TTuple(id=0, a=0, blist=[])>
>>> NTEnum.NONE.value
TTuple(id=0, a=0, blist=[])
>>> [x.value for x in NTEnum]
[TTuple(id=0, a=0, blist=[]), TTuple(id=1, a=2, blist=[4]), TTuple(id=2, a=4, blist=[0, 1, 2])]
>>> import copy
>>> x = TTuple(0, 1, [7])
>>> x
TTuple(id=0, a=1, blist=[7])
>>> copy.copy(x)
TTuple(id=0, a=1, blist=[7])
>>> copy.deepcopy(x)
TTuple(id=0, a=1, blist=[7])
>>> NTEnum.NONE.value.blist
[]

Python 3.11.1 (tags/v3.11.1:a7a450f, Dec 6 2022, 19:58:39) [MSC v.1934 64 bit (AMD64)] on win32

>>> from enum import Enum
>>> from collections import namedtuple
>>> TTuple = namedtuple('TTuple', 'id a blist')
>>> class NTEnum(Enum):
...     NONE = TTuple(0, 0, [])
...     A = TTuple(1, 2, [4])
...     B = TTuple(2, 4, [0, 1, 2])
... 
...     
>>> NTEnum.NONE
<NTEnum.NONE: (0, 0, [])>
>>> NTEnum.NONE.value
(0, 0, [])
>>> [x.value for x in NTEnum]
[(0, 0, []), (1, 2, [4]), (2, 4, [0, 1, 2])]
>>> import copy
>>> x = TTuple(0, 1, [7])
>>> x
TTuple(id=0, a=1, blist=[7])
>>> copy.copy(x)
TTuple(id=0, a=1, blist=[7])
>>> copy.deepcopy(x)
TTuple(id=0, a=1, blist=[7])
>>> NTEnum.NONE.value.blist
Traceback (most recent call last):
  File "<pyshell#16>", line 1, in <module>
    NTEnum.NONE.value.blist
AttributeError: 'tuple' object has no attribute 'blist'

Your environment

CPython versions tested on: 3.11.0, 3.11.1
Operating system and architecture: win64 (amd64)
3.11.0 additionally tested on linux
3.11.0, 3.11.1 tested in IDLE

Linked PRs

The text was updated successfully, but these errors were encountered:

…H-100099) When checking for auto() instances, only top-level usage is supported, which means either alone or as part of a regular tuple. Other containers, such as lists, dicts, or namedtuples, will not have auto() transformed into a value.

…uto (pythonGH-100099) When checking for auto() instances, only top-level usage is supported, which means either alone or as part of a regular tuple. Other containers, such as lists, dicts, or namedtuples, will not have auto() transformed into a value. (cherry picked from commit ded02ca) Co-authored-by: Ethan Furman <ethan@stoneleaf.us>

…H-100099) When checking for auto() instances, only top-level usage is supported, which means either alone or as part of a regular tuple. Other containers, such as lists, dicts, or namedtuples, will not have auto() transformed into a value. (cherry picked from commit ded02ca) Co-authored-by: Ethan Furman <ethan@stoneleaf.us>

ethanfurman · 2022-12-08T20:25:42Z

Thank you for the bug report. The fix will be in 3.11.2. If you need to use 3.11.1 you can inherit directly from TTuple:

>>> from enum import Enum
>>> from collections import namedtuple
>>> TTuple = namedtuple('TTuple', 'id a blist')
>>> class NTEnum(TTuple, Enum):
...     NONE = TTuple(0, 0, [])
...     A = TTuple(1, 2, [4])
...     B = TTuple(2, 4, [0, 1, 2])
... 
>>> NTEnum.A
<NTEnum.A: TTuple(id=1, a=2, blist=[4])>
>>> 
>>> NTEnum.A.id
1
>>> NTEnum.B.blist
[0, 1, 2]

On the up-side, the .value attribute is now a TTuple, and you can directly access the id, a, and blist attributes on the enum mebers; on the (possible) down-side, the enum member is directly comparable to tuples.

Zannick added the type-bug An unexpected behavior, bug, or error label Dec 8, 2022

ethanfurman self-assigned this Dec 8, 2022

bedevere-bot mentioned this issue Dec 8, 2022

gh-100098: [Enum] insist on actual tuples, no subclasses, for auto #100099

Merged

bedevere-bot mentioned this issue Dec 8, 2022

[3.11] gh-100098: [Enum] insist on actual tuples, no subclasses, for auto (GH-100099) #100102

Merged

ethanfurman closed this as completed Dec 8, 2022

3.11.1 Regression: namedtuple Enum values are cast to tuple #100098

3.11.1 Regression: namedtuple Enum values are cast to tuple #100098

Zannick commented Dec 8, 2022 •

edited by bedevere-bot

ethanfurman commented Dec 8, 2022 •

edited

3.11.1 Regression: namedtuple Enum values are cast to tuple #100098

3.11.1 Regression: namedtuple Enum values are cast to tuple #100098

Comments

Zannick commented Dec 8, 2022 • edited by bedevere-bot

Bug report

Your environment

Linked PRs

ethanfurman commented Dec 8, 2022 • edited

Zannick commented Dec 8, 2022 •

edited by bedevere-bot

ethanfurman commented Dec 8, 2022 •

edited