Fix authentication.requires type

[sobolevn]

I've noticed that authentication.requires does not preserve type information about the passed function.

So, I've fixed that!

from starlette.authentication import requires


@requires(['authenticated', 'admin'])
async def dashboard(request: str) -> int:  # Don't mind these fake types here
    ...

reveal_type(dashboard)
# Before:
# note: Revealed type is "Any"

# After:
# note: Revealed type is "def (request: builtins.str) -> typing.Coroutine[Any, Any, builtins.int]"

[Kludex]

I like the enthusiasm! Thanks for the PR @sobolevn ! 🙇

But... This is not the right annotation, that's why the # type: ignore was needed. Besides, I think that's something we need to discuss first, as it opens precendece to a lot of annotations in code.

For those reasons, I'll be closing this PR.

[sobolevn]

But... This is not the right annotation

It looks right to me 🤔
Can you please point out what's wrong?

This is the common way of expressing "this function returns a decorator that preserves the signature".
I might be missing something 🙂

that's why the # type: ignore was needed

type: ignore is needed, because we cannot really proove to mypy that _CallableType is the same thing as decorator. Mypy cannot inference that by default. There are two ways:

• cast() with runtime effect (small, but still)
• # type: ignore which does not have this effect

Besides, I think that's something we need to discuss first, as it opens precendece to a lot of annotations in code.

Sure thing, I will open an issue about that.
Update: #1662

[adriangb]

@Kludex I do think this is the right annotation, unless we want to be more explicit and encode Callable[[Request], Response] in there to avoid a typevar.

[Kludex]

Can we add at least the error on ignore[<error>]? 🙏

[adriangb]

Suggested change

	return decorator # type: ignore
	return decorator # type: ignore[return-value] # type checkers can't verify the type of the wrapper

[Kludex]

i'm already happy with just the return-value thingy, no need the comment stuff

[Kludex]

But... This is not the right annotation

It looks right to me thinking Can you please point out what's wrong?

This is the common way of expressing "this function returns a decorator that preserves the signature". I might be missing something slightly_smiling_face

that's why the # type: ignore was needed

type: ignore is needed, because we cannot really proove to mypy that _CallableType is the same thing as decorator. Mypy cannot inference that by default. There are two ways:

• cast() with runtime effect (small, but still)
• # type: ignore which does not have this effect

Besides, I think that's something we need to discuss first, as it opens precendece to a lot of annotations in code.

Sure thing, I will open an issue about that. Update: #1662

Thanks for the explanation! I guess I got excited closing PRs that day. 😰

I retract my words from before, and sorry for closing the PR. :)

[adriangb]

Thank you for the contribution @sobolevn !