[FastAPI] FromDishka is being refused by Pydantic

[wadinj]

Hi,

I'm facing an issue when using Pydantic with FastAPI route decorated with pydantic + Dishka

FastAPIError: Invalid args for response field! Hint: check that typing.Annotated[api.repository.UserRepository, FromComponent(component='')] is a valid Pydantic field type. 
If you are using a return type annotation
that is not a valid Pydantic field (e.g. Union[Response, dict, None]) 
you can disable generating the response model from 
the type annotation with the path operation decorator parameter response_model=None. 

The error seems to be only when using FastAPI route decorator like:
@app.get("/users/{user_id}", response_model=UserDTO)

If registration is done through add_api_route, Pydantic does not raise exception anymore:
app.add_api_route("/users/{user_id}", get_user_by_id, methods=["GET"], response_model=UserDTO)

Moreover, Dishka seems to not support FastAPI in sync mode, when using an injection on a sync endpoint, it raises:
TypeError: object list can't be used in 'await' expression from dishka/integrations/base.py:192 (as my endpoint return a list of object)
The method setup_dishka seems to take only AsyncContainer as argument

[Tishka17]

Did you forget @inject decorator? It is requried unless you explicitly enable autoinject which is not so trivial in fastapi.

We do not support sync mode yet. Actually, I do not think that using fastapi with sync view is a good idea - you loose all asyncio features and get its problems + additional. If you really need sync views I'd recommend using some WSGI-framerwork (not ASGI)

The problem with sync/async fastapi is mostly in mixing the both approaches. We can try to support sync-only mode, but anyway it looks like some guys will try to use async containers in sync code and vice versa.

[wadinj]

I did use the @inject decorator, I think all of this come from the fact I'm using sync mode. Agree that sync mode is not ideal in fastapi, but I've a large codebase already written in sync mode with some underlying libs without asyncio support yet.

Is there any plan to support sync mode? I would be interested to bring such contrib.

[Tishka17]

Try this code instead of builin integration. It should work with sync fastapi and sync container
https://github.com/Dark04072006/Simbir.Health/blob/main/services/account/src/account/presentation/dishka.py