Rule request: Detect dataclass() usage with Enum and its subclasses

[correctmost]

Motivation

There was a bug in archinstall because a dataclass decorator was incorrectly applied to an Enum:

@dataclass
class Audio(Enum):
    NoAudio = 'No audio server'
    Pipewire = 'pipewire'
    ...

The Python docs warn about such usage, but I am not aware of any linter that currently catches the error:

Adding dataclass() decorator to Enum and its subclasses is not supported. It will not raise any errors, but it will produce very strange results at runtime, such as members being equal to each other

Note: The docs mention that dataclass mixins can be used with enums, so there are some valid combinations of the constructs.

Related discussions

• Match on Enum with dataclass decorator python/cpython#114803
• gh-114803: Mention that @dataclass should not be applied on enums python/cpython#114891

Documentation

• https://docs.python.org/3/howto/enum.html#dataclass-support

Real world bugs

• audio: remove incorrect use of dataclass archlinux/archinstall#3058

[InSyncWithFoo]

There do seem to be quite a few bugs of this pattern.

[MichaReiser]

Thanks, this makes sense to me