How to make all fields required in pydantic model

Question

I have a pydantic (v2) model containing some fields with default values. I would like on some occasions for these models to be used in a "strict mode" where the default values are no longer available and every field must be supplied when using model_validate.

Is there an easy way to do this with minimal boilerplate (e.g. subclassing all the models one by one). I was hoping for maybe just an attribute to add to a model definition which would use then allow the context parameter on model_validate to be used to specify whether or not apply any default. Or maybe there is already something built into pydantic which i have missed?

Answer 1

I solved neatly by using the library https://github.com/zmievsa/cached_classproperty and the following code

from cached_classproperty import cached_classproperty
from pydantic import BaseModel, create_model, ConfigDict
from pydantic_core import PydanticUndefined
from typing import Any

class StrictModel(BaseModel):

    model_config = ConfigDict(ignored_types=(cached_classproperty,))

    @cached_classproperty
    def Strict(cls, **kwargs: Any):
        m = create_model(
            cls.__name__,
            __base__ = cls
        )

        for field in m.model_fields.values():
            field.default = PydanticUndefined

        m.model_rebuild(force=True)
        
        return m

########################################################################

class Foo(StrictModel):
    a: int = 2
    b: int = 2


foo = Foo(a=1)
print(foo) #a=1 b=2

bar = Foo.Strict(a=1) #validation error as b not supplied