asyncio.Event.wait() doesn't seem to be cancelled by asyncio.wait_for(). Ctrl-c in the attached example produces output below. I'm not certain the code is correct though the documentation for wait_for() suggests it should work. Without the wait_for() it doesn't suffer from pending task destruction. This is Python 3.4.3. 


Hello World!
Hello World!
^CTraceback (most recent call last):
  File "./loop2.py", line 27, in <module>
    loop.run_until_complete(hello_world())
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py", line 304, in run_until_complete
    self.run_forever()
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py", line 276, in run_forever
    self._run_once()
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py", line 1136, in _run_once
    event_list = self._selector.select(timeout)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/selectors.py", line 502, in select
    kev_list = self._kqueue.control(None, max_ev, timeout)
KeyboardInterrupt
Task was destroyed but it is pending!
task: <Task pending coro=<wait() running at /Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/locks.py:242> wait_for=<Future pending cb=[Task._wakeup()]> cb=[_release_waiter(<Future pendi...sk._wakeup()]>)() at /Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/tasks.py:335]>
[1]    8134 exit 1     ../venv3/bin/python3 ./loop2.py

KeyboardInterrupt is not handled gently by asyncio (see https://groups.google.com/d/msg/python-tulip/sovg7EIBoXs/m7U-0UXqzSQJ)

you could cancel all tasks in the signal handler:

...

def sig_interrupt():
    print('interrupt')
    for task in asyncio.Task.all_tasks():
        task.cancel()

loop.add_signal_handler(signal.SIGINT, sig_interrupt)
...

Duplicate for #39622