Can't use query parameters in websocket route without path

[xd009642]

Summary

async fn ws_handler_pathless(
    ws: WebSocketUpgrade,
    headers: HeaderMap,
    params: Query<HashMap<String, String>>,
    mocks: Extension<MockList>,
) -> Response {
    ws_handler(ws, Path(String::new()), headers, params, mocks).await
}

async fn ws_handler(
    ws: WebSocketUpgrade,
    Path(path): Path<String>,
    headers: HeaderMap,
    Query(params): Query<HashMap<String, String>>,
    mocks: Extension<MockList>,
) -> Response {
    // SNIP IRRELEVANT CODE
 
    ws.on_upgrade(|socket| async move { handle_socket(socket, mocks).await })
}

impl MockServer {

    pub async fn start() -> Self {
        let mocks: MockList = Default::default();

        let router = Router::new()
            .route("/{*path}", any(ws_handler))
            .route("/", any(ws_handler_pathless))
            .layer(Extension(mocks.clone()));

        let listener = tokio::net::TcpListener::bind("0.0.0.0:0").await.unwrap();
        let addr = format!("ws://{}", listener.local_addr().unwrap());

        debug!("axum listening on: {}", addr);

        let (tx, rx) = oneshot::channel();
        let listening_server = axum::serve(listener, router).with_graceful_shutdown(async move {
            let _ = rx.await;
        });

        tokio::task::spawn(listening_server.into_future().in_current_span());

        Self {
            addr,
            shutdown: Some(tx),
            mocks,
        }
    }
    
    pub fn uri(&self) -> &str {
        &self.addr
    }
}

If I try to connect to format!("{}?query=param", server.uri()) with tokio-tungstenite connect_async I get a 400 bad request. If I then try to connect with format!("{}/path?query=param", server.uri()) it works.

I think it should be perfectly fine to use query parameters in a websocket without a path parameter also present - but I'm not 100% on that and google isn't very helpful (results are mainly JS people asking if query parameters exist with websockets...). Hence the discussion not an issue.

It seems tungstenite works as I'd expect because if I just change the addr to one not present I get a connection refused so it is connecting to axum and getting the bad request back not trying to substitute it's own thing (afaict)

axum version

0.8.1