On Mon, Feb 11, 2013 at 2:23 PM, Saúl Ibarra Corretgé <saghul@gmail.com> wrote:


I think there are actually two cases: where stop() is called from the
task given to run_until_complete(), or from another task. In the former
case, because the exception bubbles out of the task's coroutine, the
task will be marked as done (and its exception set to _StopError) -- at
least I think so. In the latter case, the task will still be runnable,
and it will continue to run when the event loop is started again. (Hm...
maybe run_forever() should be called start(), to match stop()?)

I think your unittest only tests the former case.


Well, I think they are actually the same. In the gist I posted earlier I called loop.stop(), I didn't raise the exception inside the task, and loop.stop() will call call_soon so the actual raising will happen in the context on _run_once unless I'm mistaken.

Oh, you're right! Not my day for reading carefully. :-)
 
Here is an updated simple test with it's output: https://gist.github.com/saghul/4758151


I'm not sure what run_until_complete() should return in the latter case.
In fact it makes me doubt the behavior of run_until_complete() in
general. Maybe it should return the Future (although that's kind of
redundant)? Or an enum indicating what happened? (Cases would be result,
exception, timeout, running -- and maybe cancelled?)


I think the current behavior is ok, it the user really wants to check if the future was actually completed she can check with done(), if she saved the future in a variable, that is.

My other preferred approach would be to raise an exception, since I consider this an exceptional case: I told the loop to run until this future is completed so I expect that to happen. Since it didn't, NotCompletedError (or something alike) sounds good to me.

Good. How about calling future.result(), and letting it raise InvalidStateError ? (Except if the timeout handler was called.)

--
--Guido van Rossum (python.org/~guido)