Should SomeStrEnum(str, Enum) require SLOT000?

[charliermarsh]

Discussed in #5747

^{Originally posted by jamesbraza July 13, 2023}
Please see the below file with Python 3.10.10:

from enum import Enum

class SomeStrEnum(str, Enum):
    KEY = "value"

Running ruff==0.0.278 on this:

> ruff --isolated --select="SLOT" a.py
a.py:3:7: SLOT000 Subclasses of `str` should define `__slots__`
Found 1 error.

Running flake8-slots==0.1.5 with flake8==4.0.1 on this, there's no error:

> flake8 a.py

Fwiw, Python 3.11's built-in enum.StrEnum doesn't seem to define __slots__.

I am not sure if there should or should not be SLOT000 for this. Looks like @qdegraaf added SLOT rule in ruff==0.0.273, so notifying him.

I am thinking either:

• This is a false positive of SLOT000
• Or should the built-in StrEnum define __slots__?

[charliermarsh]

Looks like flake8-slots omits enums: https://github.com/python-formate/flake8-slots/blob/0b1ecb9076c6194f29265b7bfb904d63073bce08/flake8_slots/__init__.py#L102.

[sujuka99]

Is this expected?

class SuperEnum(Enum):
	...

class CustomStrEnum(str, SuperEnum):  # Results in "SLOT000 Subclasses of `str` should define `__slots__`"
	...

[charliermarsh]

Yeah, we don't trace across base classes right now. You'd need to add Enum as a parent class to have it detected properly.

[sujuka99]

Yeah, we don't trace across base classes right now. You'd need to add Enum as a parent class to have it detected properly.

Thanks for the quick answer :)