Cannot set pydantic config options on model via class kwargs

[jeffchase]

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Example Code

from sqlmodel import SQLModel


class Test(SQLModel, arbitrary_types_allowed=True):
    id: int


print(Test.model_config)

Description

Setting model config parameters as class kwargs doesn't work when using pydantic v2:

from sqlmodel import SQLModel


class Test(SQLModel, arbitrary_types_allowed=True):
    id: int


print(Test.model_config)

>>> import test
{'from_attributes': True, 'registry': PydanticUndefined}
# missing arbitrary_types_allowed

This is caused by a bug in the meta-class:

sqlmodel/sqlmodel/main.py

Lines 529 to 535 in 4bac032

	allowed_config_kwargs: Set[str] = {
	key
	for key in dir(BaseConfig)
	if not (
	key.startswith("__") and key.endswith("__")
	) # skip dunder methods and attributes
	}

where allowed_config_kwargs is {'copy', 'pop', 'values', 'keys', 'fromkeys', 'items', 'update', 'setdefault', 'popitem', 'get', 'clear'}

With Pydantic v2, BaseConfig is aliased to ConfigDict which doesn't have the config keys as attributes.

Operating System

Linux

Operating System Details

No response

SQLModel Version

0.0.24

Python Version

3.13.2

Additional Context

Pydantic version: 2.11.7

[Muguett-DBY]

Using model_config is a working alternative to the class keyword here:

from pydantic import ConfigDict
from sqlmodel import SQLModel


class Test(SQLModel):
    model_config = ConfigDict(arbitrary_types_allowed=True)
    id: int


assert Test.model_config["arbitrary_types_allowed"] is True
assert Test.model_config["from_attributes"] is True

Pydantic merges this with inherited configuration, so SQLModel's from_attributes=True remains in place.

I reproduced the dropped class keyword on both SQLModel 0.0.24/Pydantic 2.11.7 and SQLModel 0.0.48/Pydantic 2.14.1. On both, the model_config form also successfully validates a field annotated with a custom class, while rejecting an instance of the wrong class. Checked with Codex assistance. This works around the metaclass issue; it doesn't fix the keyword form itself.