Pending asyncQueue.waiting() Task in langgraph causes "Task was destroyed but it is pending!"

[dmsthd]

I am using the langgraph library and running asynchronous execution inside the run_graph() function, which awaits graph.ainvoke().

I create task with asyncio.create_task(run_graph()) and call cancel() on it when needed. Although the cancellation log in run_graph() is printed properly, the internal Task asyncQueue.waiting() created by langgraph remains pending and does not get cancelled properly.

[ERROR] asyncio: Task was destroyed but it is pending!
source_traceback: Object created at (most recent call last):
  File "<string>", line 1, in <module>
  File ".pyenv/versions/3.11.4/lib/python3.11/multiprocessing/spawn.py", line 120, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File ".pyenv/versions/3.11.4/lib/python3.11/multiprocessing/spawn.py", line 133, in _main
    return self._bootstrap(parent_sentinel)
  File ".pyenv/versions/3.11.4/lib/python3.11/multiprocessing/process.py", line 314, in _bootstrap
    self.run()
  File ".pyenv/versions/3.11.4/lib/python3.11/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File ".venv/lib/python3.11/site-packages/uvicorn/_subprocess.py", line 80, in subprocess_started
    target(sockets=sockets)
  File ".venv/lib/python3.11/site-packages/uvicorn/server.py", line 67, in run
    return asyncio.run(self.serve(sockets=sockets))
  File ".pyenv/versions/3.11.4/lib/python3.11/asyncio/runners.py", line 190, in run
    return runner.run(main)
  File ".pyenv/versions/3.11.4/lib/python3.11/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
  File ".venv/lib/python3.11/site-packages/langgraph/pregel/main.py", line 3112, in ainvoke
    async for chunk in self.astream(
  File ".venv/lib/python3.11/site-packages/langgraph/pregel/main.py", line 2939, in astream
    async for _ in runner.atick(
  File ".venv/lib/python3.11/site-packages/langgraph/pregel/_runner.py", line 380, in atick
    futures[get_waiter()] = None
  File ".venv/lib/python3.11/site-packages/langgraph/pregel/main.py", line 2927, in get_waiter
    return aioloop.create_task(stream.wait())
task: <Task pending name='Task-167' coro=<AsyncQueue.wait() running at .venv/lib/python3.11/site-packages/langgraph/_internal/_queue.py:33> wait_for=<Future pending cb=[Task.task_wakeup()] created at .venv/lib/python3.11/site-packages/langgraph/_internal/_queue.py:28> created at .venv/lib/python3.11/site-packages/langgraph/pregel/main.py:2927>

The run_graph() coroutine catches the cancellation and logs it, but the internal asyncQueue.waiting() Task remains alive.

Any advice on how to properly cancel and cleanup asyncQueue.waiting() Task or if there is a recommended way to manage graceful shutdown with langgraph would be appreciated.

Environment

• Python version: 3.11.4
• langgraph version: 0.6.4
• Framework: FastAPI