RuntimeError if websocket client disconnects from the server before websocket connection is accepted

[invisibleroads]

During server shutdown (i.e. CTRL-C), uvicorn raises a RuntimeError if a websocket client disconnected from the server before the websocket connection was accepted.

ERROR:    ASGI callable returned without sending handshake.
INFO:     connection closed                                                                                                                       
ERROR:asyncio:Task exception was never retrieved
future: <Task finished name='Task-6' coro=<WebSocketProtocol.run_asgi() done, defined at $VIRTUAL_ENV/lib64/python3.12/site-packages/uvicorn/protocols/websockets/websockets_impl.py:234> exception=RuntimeError('unable to perform operation on <TCPTransport closed=True reading=False 0x56278210bc40>; the handler is closed')>
Traceback (most recent call last):
  File "$VIRTUAL_ENV/lib64/python3.12/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 258, in run_asgi
    self.send_500_response()
  File "$VIRTUAL_ENV/lib64/python3.12/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 218, in send_500_response
    self.transport.write(b"".join(content))
  File "uvloop/handles/stream.pyx", line 674, in uvloop.loop.UVStream.write
  File "uvloop/handles/handle.pyx", line 159, in uvloop.loop.UVHandle._ensure_alive
RuntimeError: unable to perform operation on <TCPTransport closed=True reading=False 0x56278210bc40>; the handler is closed

The offending code is in https://github.com/encode/uvicorn/blob/master/uvicorn/protocols/websockets/websockets_impl.py

    def send_500_response(self) -> None:
        msg = b"Internal Server Error"
        content = [
            b"HTTP/1.1 500 Internal Server Error\r\n" b"content-type: text/plain; charset=utf-8\r\n",
            b"content-length: " + str(len(msg)).encode("ascii") + b"\r\n",
            b"connection: close\r\n",
            b"\r\n",
            msg,
        ]
        self.transport.write(b"".join(content))    # <== !!!

I think we can safely wrap the transport.write in a try catch:

        try:
            self.transport.write(b"".join(content))
        except RuntimeError:
            pass

[invisibleroads]

Please see master...invisibleroads:uvicorn:patch-3

[Kludex]

This is an issue with uvloop. I've written an MRE on their side: MagicStack/uvloop#506 (comment)