Problem

We use "before" validators to read data from a file input and transform it. According to pydantic (pydantic/pydantic#468) and a user on Stack (https://stackoverflow.com/a/72362147/8557834), that is what you should do, although I'm not sure this is still the case today or if there are better options.

Yet, this plugin does not pickup such transformations in the "before" validator:

from pydantic import BaseModel, field_validator


class BeforeValidationTransformModel(BaseModel):
    real_value: float

    @field_validator('real_value', mode='before')
    def _convert_version(cls, input_value: Any) -> float:
        if isinstance(input_value, str):
            return 2.54
        return input_value


model = BeforeValidationTransformModel(real_value='a string')

print(model)

Potential solution

Incorporate the typing from the "before" validation method and expect a union.

Alternative solution

Suggest to replace "before" validators with better alternatives.