mutable-class-default (RUF012) misinterprete the code block

[ArazHeydarov]

Hello,

RUF012 working principle seems to be broken. I'm defining a Pydantic json_encoder config however Ruff detects it as typing annotation and raises an error when I check.

Code:

from bson import ObjectId
from pydantic import BaseConfig, BaseModel


class MongoModel(BaseModel):
    class Config(BaseConfig):
        allow_population_by_field_name = True
        json_encoders = {ObjectId: str}

Command: ruff check .

Result:

src/models/mongo_model.py:8:25: RUF012 Mutable class attributes should be annotated with `typing.ClassVar`
Found 1 error.

Current settings:

[tool.ruff.lint]
extend-select = ["I", "C90", 'N', 'UP', 'ASYNC', 'RUF']

Current Ruff version:
ruff 0.1.14

[charliermarsh]

It looks like BaseConfig is missing from our allowlist.

[charliermarsh]

What is BaseConfig? I can't find it in the Pydantic docs.

[trag1c]

What is BaseConfig? I can't find it in the Pydantic docs.

It's part of Pydantic v1: https://docs.pydantic.dev/2.0/api/config/#pydantic.config.BaseConfig

[ArazHeydarov]

It's a class that is deprecated as of Pydantic 2.0. The result is the same without inheriting from that class.
I know that the Config class definition itself is deprecated.

[charliermarsh]

Thank you! Will add.

[ArazHeydarov]

Thank you for your quick response.