Deprecate stream.unread_data

[asvetlov]

stream.unread_data() is a leaking abstracton: it violates chunk boundaries at least.
Aso, it prevents some optimizations.

The call is used in multipart. We already have MultipartBodyReader._unread buffer, replacement stream.unread_data() wit appending to self._unread looks feasible.

[asvetlov]

@kxepal I need your help
Can you spend a bit of your spare time on replacement stream.unread_data() with adding a read chunk into self._unread in multipart?

aiohttp 3.5 is going to be the latest 3.x release; I'd like to deprecate the method now and remove it entirely in aiohttp 4.0

[kxepal]

Ok, will do that, tomorrow (6.12).

[asvetlov]

Thanks!

[kxepal]

That seems wouldn't be too easy. We relay too much on that stream unread_data in different places and it serves a little bit different purpose than internal _unread - those one holds whole lines, while we have to unread arbitrary chunks of data. Mixing them breaks a lot.

I feel that I would have just to reimplement those stream unread logic on multipart side, what may be no very cool, but at least it will hold all the bits and not depend on foreign state.

[asvetlov]

@kxepal thanks for the status update.

I need your opinion: can we live with #3439 for a while? I don't want to block the release on the issue

[kxepal]

Yes, we can. For 4.0 we'll fix this issue.

[asvetlov]

@kxepal thanks!

[asvetlov]

Fixed by #3439

[lock]

This thread has been automatically locked since there has not been
any recent activity after it was closed. Please open a new issue for
related bugs.

If you feel like there's important points made in this discussion,
please include those exceprts into that new issue.