On Fri, Oct 13, 2017 at 1:45 PM, Ethan Furman <et...@stoneleaf.us> wrote: > On 10/13/2017 09:48 AM, Steve Dower wrote: >> >> On 13Oct2017 0941, Yury Selivanov wrote: > > >>> Actually, capturing context at the moment of coroutine creation (in >>> PEP 550 v1 semantics) will not work at all. Async context managers >>> will break. >>> >>> class AC: >>> async def __aenter__(self): >>> pass >>> >>> ^ If the context is captured when coroutines are instantiated, >>> __aenter__ won't be able to set context variables and thus affect the >>> code it wraps. That's why coroutines shouldn't capture context when >>> created, nor they should isolate context. It's a job of async Task. >> >> >> Then make __aenter__/__aexit__ when called by "async with" an exception to >> the normal semantics? >> >> It seems simpler to have one specially named and specially called function >> be special, rather than make the semantics >> more complicated for all functions. >
It's not possible to special case __aenter__ and __aexit__ reliably (supporting wrappers, decorators, and possible side effects). > +1. I think that would make it much more usable by those of us who are not > experts. I still don't understand what Steve means by "more usable", to be honest. Yury _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
