Django channels raises TypeError on close: An asyncio.Future, a coroutine or an awaitable is required

[Rodrigo Bistolfi]

Hi there,

I am using Channels 2.1.7 with Python 3.7.2.
My consumer does this on connect:

async def connect(self):
    """Accept connect if user has been provided by middleware"""  
    self.user = self.scope.get('user')
    if self.user:
        await self.accept()
    else:
        await self.close()

When `self.close()` is called, an exception is raised:

Traceback (most recent call last):
  File "/opt/sps/.venv/lib/python3.7/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 147, in run_asgi
    result = await asgi(self.asgi_receive, self.asgi_send)
  File "/opt/sps/.venv/lib/python3.7/site-packages/channels/consumer.py", line 59, in __call__
    [receive, self.channel_receive], self.dispatch
  File "/opt/sps/.venv/lib/python3.7/site-packages/channels/utils.py", line 59, in await_many_dispatch
    await task
  File "/opt/sps/.venv/lib/python3.7/site-packages/channels/utils.py", line 51, in await_many_dispatch
    result = task.result()
  File "/opt/sps/.venv/lib/python3.7/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 227, in asgi_receive
    data = await self.recv()
  File "/opt/sps/.venv/lib/python3.7/site-packages/websockets/protocol.py", line 420, in recv
    return_when=asyncio.FIRST_COMPLETED,
  File "/usr/local/lib/python3.7/asyncio/tasks.py", line 361, in wait
    fs = {ensure_future(f, loop=loop) for f in set(fs)}
  File "/usr/local/lib/python3.7/asyncio/tasks.py", line 361, in <setcomp>
    fs = {ensure_future(f, loop=loop) for f in set(fs)}
  File "/usr/local/lib/python3.7/asyncio/tasks.py", line 592, in ensure_future
    raise TypeError('An asyncio.Future, a coroutine or an awaitable is '
TypeError: An asyncio.Future, a coroutine or an awaitable is required

The relevant code seems to be this:

while len(self.messages) <= 0:
    pop_message_waiter = asyncio.Future(loop=self.loop)
    self._pop_message_waiter = pop_message_waiter
    try:
        # If asyncio.wait() is canceled, it doesn't cancel
        # pop_message_waiter and self.transfer_data_task.
        tasks = [pop_message_waiter, self.transfer_data_task]
        yield from asyncio.wait(
            tasks,
            loop=self.loop,
            return_when=asyncio.FIRST_COMPLETED,
        )
    finally:
        self._pop_message_waiter = None

In websockets/protocol.py line 410 and ss, `self.trasfer_data_task` is `None`. If I remove it from the wait list it seems to work.
Any ideas?

Thanks in advance, Rodrigo