[Async-sig] Asynchronous cleanup is a problem

[Nathaniel Smith]

On Wed, Jul 6, 2016 at 6:17 PM, Yury Selivanov <yselivanov at gmail.com> wrote:
>
>> ...does it actually work to re-enter a main loop from inside a __del__
>> callback? It seems like you could get into really nasty states with
>> multiple nested __del__ calls, or if a single sweep detects multiple
>> pieces of garbage with __del__ methods, then some of those __del__
>> calls could be delayed indefinitely while the first __del__ runs. Is
>> the cycle collector even re-entrant?
>
> We can have a flag on the async gen object to make sure that we run the finalizer only once. The finalizer will likely schedule async_gen.aclose() coroutine which will ensure a strong ref to the gen until it is closed. This can actually work.. ;)

Hmm, if the strategy is to schedule the work to happen outside of the
actual __del__ call, then I think this is back to assuming that all
coroutine runners are immortal and always running. Is that an
assumption you're comfortable with?

-n

-- 
Nathaniel J. Smith -- https://vorpus.org