on_connect and on_disconnect type hints

[jhk-mjolner]

I'm using fastapi_websocket_rpc's on_connect callbacks on WebsocketRPCEndpoint. And it works. But when I use pyright to statically check the types, I get errors.

I define the callbacks like async def on_client_connect(self, channel: RpcChannel): and give them as WebsocketRPCEndpoint(on_connect=[self.on_client_connect]).

Pyright gives errors like

error: Argument of type "list[(channel: RpcChannel) -> Coroutine[Any, Any, None]]" cannot be assigned to parameter "on_connect" of type "List[Coroutine[Unknown, Unknown, Unknown]]" in function "__init__"
    "function" is incompatible with "Coroutine[Unknown, Unknown, Unknown]" (reportGeneralTypeIssues)

Looking further into it. It seems like the type hinting in WebsocketRPCEndpoint constructor doesn't quite match what it will accept at runtime.

A place I've looked: https://stackoverflow.com/a/59177557 and its comments

If I've understood correctly, a better type hint would be List[Callable[[RpcChannel], Awaitable[Any]]] instead of List[Coroutine] to say that it takes a list of something callable that will get an RpcChannel parameter, and that when called, should return something awaitable that can return anything.
At least pyright is happy if I modify the library code to have that type hint.

Is this something that you're interested in changing?

For now I'll use # type: ignore comments to disable type checking when constructing WebsocketRPCEndpoint

[asafc]

Hi @jhk-mjolner thanks for reporting!

We would be willing to review a PR, if you'd be interested in contributing this fix.
cc @roekatz