[BUG] CBV interaction with url_for

[dp-rufus]

I've just run into this issue in the wild. It's not a bug as such, but perhaps there's a way to prevent it catching people out like it did me?

Consider this example:

from fastapi import APIRouter, FastAPI, Request
from fastapi_utils.cbv import cbv

router = APIRouter()


@cbv(router)
class Foo:
    @router.get("/foo")
    async def example(self, request: Request):
        return request.url_for("example")


@cbv(router)
class Bar:
    @router.get("/bar")
    async def example(self, request: Request):
        return request.url_for("example")


app = FastAPI()
app.include_router(router)

Both of the url_for("example") calls return "/foo", whereas the expected behaviour might be for the second one to return "/bar" instead.

Without CBVs, IDEs and linters would warn about the function example being redefined, but it obviously doesn't when they're in two different classes. So the problem goes unnoticed until runtime, at which point the 'wrong' path is used.

If we made a change like this to cbv.py...

    for route in cbv_routes:
        router.routes.remove(route)
        _update_cbv_route_endpoint_signature(cls, route)
        route.name = cls.__name__ + '.' + route.name  # <-------------- this line is new
        cbv_router.routes.append(route)
    router.include_router(cbv_router)
    return cls

...then we could do url_for("Foo.example") or url_for("Bar.example").

However:

• It would need to be backwards compatible, although I don't see any immediate problem with inserting the same route twice with two different names
• It wouldn't stop the problem happening if two different modules both had CBVs with the same name, each containing a method with the same name
• It wouldn't play nicely with from x import Y as Z, if this matters - it would still use the name Y.whatever

Do you think this is worth addressing somehow? Thanks!

[yuval9313]

That does seems troublesome, Do you have any other ideas?
(since I don't actually want to use package ref inside strings e.g. "foo.example")