Repository navigation
3.11.1 Regression: namedtuple Enum values are cast to tuple #100098
Description
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
Activity
gh-100098: [Enum] insist on actual tuples, no subclasses, for auto (G…
pythongh-100098: [Enum] insist on actual tuples, no subclasses, for a…
gh-100098: [Enum] insist on actual tuples, no subclasses, for auto (G…
ethanfurman commentedon Dec 8, 2022
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:On the up-side, the
.valueattribute is now aTTuple, and you can directly access theid,a, andblistattributes on the enum mebers; on the (possible) down-side, the enum member is directly comparable to tuples.tzaffi commentedon Dec 16, 2022
FYI, you can achieve equivalent functionality on python 3.11.1 for
typing.NamedTupleusingdataclassesas follows:Modify namedtuple access