mypy doesn't complain about non-existent attributes when setting

[samskiter]

Initial Checks

• I confirm that I'm using Pydantic V2

Description

Related: #245

The above issue is fixed for getting attributes when using the pydantic mypy plugin, but not for setting attributes

Example Code

class blah(pydantic.BaseModel):

    temperature: Optional[int] = pydantic.Field(
        ..., description="The temperature of the zone"
    )
    zone: int = pydantic.Field(..., description="The zone number")


myblah = blah(temperature=1, zone=2)
myblah.sdlkjdshljkdsj = "wekjhe" <<< # does not generate an error

print(myblah.aaa) # <<< Generates an error

Python, Pydantic & OS Version

python -c "import pydantic.version; print(pydantic.version.version_info())"
             pydantic version: 2.6.3
        pydantic-core version: 2.16.3
          pydantic-core build: profile=release pgo=true
                 install path: /Users/samduke/Development/tado-playground/hub_rpi/.venv/lib/python3.11/site-packages/pydantic
               python version: 3.11.8 (main, Feb  6 2024, 21:21:21) [Clang 15.0.0 (clang-1500.1.0.2.5)]
                     platform: macOS-14.1-arm64-arm-64bit
             related packages: typing_extensions-4.10.0 mypy-1.8.0
                       commit: unknown

[samskiter]

Workaround:

Adding an @no_type_check decorator to setattr:

class blah(pydantic.BaseModel):
    @no_type_check
    def __setattr__(self, name: str, value: json.Any) -> None:
        return super().__setattr__(name, value)

    temperature: Optional[int] = pydantic.Field(
        ..., description="The temperature of the zone"
    )
    zone: int = pydantic.Field(..., description="The zone number")

[Viicos]

Hum, are you certain this is an issue on latest? I believe this was fixed in #8651.

Those dunder methods are currently defined in a if not TYPE_CHECKING block, however it might be interesting to use no_type_check, would avoid the extra indentation block

[sydney-runkle]

Closing for now, as I believe this is fixed on main and will be in 2.7.0b1. Feel free to ping me if you run a test that proves otherwise!