bpo-43216: Remove @asyncio.coroutine

[illia-v]

@asyncio.coroutine was scheduled for removal in Python 3.10 originally.

https://bugs.python.org/issue43216

[vstinner]

cc @1st1 @asvetlov

[vstinner]

LGTM. But I would prefer that @1st1 or @asvetlov merged it.

I only quickly looked at test changes. I'm fine with removing legacy @asyncio.coroutine, async def is now standard and preferred.

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[graingert]

This isn't stale

[graingert]

@1st1 @asvetlov

[vstinner]

multiprocessing tests hang on Address sanitizer. I cannot merge the PR because of it :-(

cc @pablogsal

[pablogsal]

multiprocessing tests hang on Address sanitizer. I cannot merge the PR because of it :-(

That's weird. Maybe run them again? We can look into increasing timeout for that run or excluding those

[vstinner]

Merged, thanks.

I decided to no longer wait for @1st1 or @asvetlov since they seem to be busy. The change looks reasonable.

If this change breaks too many asyncio project, we can consider to revert it, help projects to migrate, and reschedule the removal once enough projects migrated. I hope that in 2021, most projects are now written with "async def" and "await". The @coroutine syntax is a legacy of Python 3.4-3.5 era. I know that one of reasons why Instagram migrated from Python 2.7 to 3.6 is to get async def syntax!

[graingert]

@vstinner did this miss the deadline for py3.10 backport?

[illia-v]

Thanks @vstinner & @graingert!

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@vstinner did this miss the deadline for py3.10 backport?

This removal was discussed shortly before the 3.10 feature freeze. Victor suggested to wait for Python 3.11 to remove the decorator.

[vstinner]

This removal was discussed shortly before the 3.10 feature freeze. Victor suggested to wait for Python 3.11 to remove the decorator.

Exactly ;-)