ruff-mutable-default (RUF008) not not catching mutable default passed to attrs.field.

[ashb]

Simple repro case

❯ cat tst.py
import attrs

@attrs.define
class B :
    mutable_default: list[int] = []
    mutable_default2: list[int] = attrs.field(default=[])

❯ uvx [email protected] check --extend-select RUF008,B006 --preview -n --isolated  tst.py
All checks passed!

Originally posted by @ashb in #14327 (comment)

Output:

tst.py:5:34: RUF008 Do not use mutable default values for dataclass attributes
  |
3 | @attrs.define
4 | class B :
5 |     mutable_default: list[int] = []
  |                                  ^^ RUF008
6 |     mutable_default2: list[int] = attrs.field(default=[])
  |

I was hoping it would catch the same error on mutable_default2

[MichaReiser]

Can you tell me more about what diagnostics you'd expect?

E.g. this raises RUF012 for the mutable_default field https://play.ruff.rs/98850596-5ef1-4a1e-a3e5-fa07ed757a81

[MichaReiser]

Shouldn't it be @attrs.define instead of @attrs.deinfe?

[ashb]

🤦🏻 Okay, so that fixes the first one, but not the second. I guess it's up for debate if the second should be caught or not.

Updated top post

[MichaReiser]

Thanks for updating the summary. Adding support for attrs.field (in preview) does make sense to me, considering that #14327 (comment) introduced attrs support.