awaitable_attrs in sqlmodel v 0.0.24 not available

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Example Code

def get_engine():
    engine = create_async_engine(
        database_url
    )
    return engine

async_session_maker = async_sessionmaker(
    get_engine(),
    class_=AsyncSession,
    expire_on_commit=False,
    autoflush=True,
    autocommit=False,
)

async def get_session() -> AsyncGenerator[AsyncSession, None]:
    async with async_session_maker() as session:
        try:
            yield session
        except Exception:
            await session.rollback()  # Rollback on exception
            raise

# Worked in 0.0.22 but does not work in 0.0.24
@router.get(
    "/users/{user_id}/groups", response_model=list[UserGroupPublic]
)
async def get_user_groups_ep(
    user_id: int,
    session: AsyncSession = Depends(get_session),
):
    user: User | None = (
        await session.exec(select(User).where(User.id == user_id))
    ).first()
    if not user:
        return HTTPException(status_code=404, detail="User not found")
    return data=await user.awaitable_attrs.groups

Description

I have a toy Fast API project (using sqlmodel for db interactions) with an endpoint that returns a user's groups. This works fine in 0.0.22 but when using 0.0.24 I get an Attribute error (see below) . I tried looking for info about awaitable attrs in the release notes but couldn't find anything.

I understand I can do selectinload / joinedload etc to solve my issue in this instance. Was the behaviour of lazy loading (in an async context) changed? If so, how can it be done now?

File "/usr/local/lib/python3.12/site-packages/pydantic/main.py", line 989, in getattr
raise AttributeError(f'{type(self).name!r} object has no attribute {item!r}')
AttributeError: 'User' object has no attribute 'awaitable_attrs'

Operating System

Linux

Operating System Details

No response

SQLModel Version

0.0.24

Python Version

3.12

Additional Context

No response

[kokoc30]

awaitable_attrs is supplied by SQLAlchemy’s AsyncAttrs mixin. Using AsyncSession does not add it to model instances. Check whether the actual User class inherits that mixin:

from sqlalchemy.ext.asyncio import AsyncAttrs

print(issubclass(User, AsyncAttrs))

If it does not, add AsyncAttrs to your existing model’s bases, keeping its fields and relationship definitions:

from sqlalchemy.ext.asyncio import AsyncAttrs
from sqlmodel import SQLModel

# Class-header change; retain your existing User model body.
class User(AsyncAttrs, SQLModel, table=True):
    ...

You can also put the mixin on a shared non-table SQLModel base inherited by your table models. If you already have a UserBase, retain that base instead of replacing it and losing its fields. Then, while user is attached to the open async session:

return await user.awaitable_attrs.groups

SQLAlchemy added AsyncAttrs in 2.0.13; see its API documentation.

I checked the SQLModel base definitions in 0.0.22 and 0.0.24: neither base adds AsyncAttrs automatically. Since the question does not show User or its bases, I cannot establish why the earlier environment exposed that property. Compare the model inheritance/imports as well as the SQLAlchemy dependency versions between the two environments. This AttributeError occurs before a relationship load is attempted, so it does not itself demonstrate changed lazy-loading behavior. I have not reproduced your application.