Force pydantic to evaluate computed_field on instantiation

[c3101]

When create a model instance, computed_field is not actually computed. It's deferred to later when the property of that instance is actually requested.

In my instance, I need to build a rather complicated model, and need to do a lot of field validation. The only input to the model will be a byte array, and all properties of the model needs to be computed using the computed_field decorator.

Here is a overly simplistic example of the problem:

from pydantic import BaseModel, computed_field
from enum import Enum


class MySuperSpecificException(Exception):
    """We have to handle this in special ways"""

    def __init__(self, response_code):
        super().__init__(f"Non-zero HSM reponse received: {response_code}")


class RepsonseCode(Enum):
    NO_ERROR = "00"
    VERIFICATION_FAILURE = "01"


class Thing(BaseModel):
    raw_bytes: bytes

    @computed_field
    @property
    def message_size(self) -> int:
        hex_value = self.raw_bytes[0:2].hex()
        return int(hex_value, 16)

    @computed_field
    @property
    def full_message(self) -> str:
        return self.raw_bytes[2:].decode()

    @computed_field
    @property
    def response_code(self) -> RepsonseCode:
        _response_code = RepsonseCode(self.full_message[0:2])

        if _response_code != RepsonseCode.NO_ERROR:
            raise MySuperSpecificException(response_code=_response_code)

        else:
            return _response_code


def main():
    data: bytes = b"\x00/00AB12"
    thing1: Thing = Thing(raw_bytes=data)

    data: bytes = b"\x00/01AB12"
    thing2: Thing = Thing(raw_bytes=data)  # no exception was raised here

    print(f"Only here, when working with the model, do we get the exception: {thing2}")


if __name__ == "__main__":
    main()

Is there a way to force pydantic, to compute the computed_field fields upon instantiation?
This isn't an expensive operation, so we don't mind doing it as often as required, but need to catch bad data early in our pipeline.

I tried creating a field_validator for the property as well, that didn't seem to work either.