`multipart.py` type annotations mismatch documentation

[kornicameister]

Long story short

Problem lies in a mismatch between the documentation of multipart here and the actual code execution around courotines __anext__, next.

Expected behaviour

Code annotations are matching the documentation and therefore expected behavior.

Actual behaviour

As a developer, I didn't notice that multipart reader behavior is actually not as straightforward as it seemed to be. Reading the documentation again, revealed to me what should be expected in here however I would expect that mypy tells me that I need to account for that behavior.

Steps to reproduce

None that I can think of. Code works fine, only annotations need tuning.

Your environment

• aiohttp (3.5.4)
• server

[kornicameister]

@asvetlov since I've only "collaborated" with you in the past. I am working now on improving those annotations a bit. If you're interested I might push a patch in a day or two.

[aio-libs-bot]

GitMate.io thinks the contributor most likely able to help you is @asvetlov.

Possibly related issues are #120 (Documentation), #3230 (iter_chunks type annotation wrong), #558 (Documentation improvement), #3240 (Missing type annotations in pyi files), and #2478 (Documentation reorganizing ).

[kornicameister]

Ok, it went a bit faster. Can't exactly test that, something is off in my environment and can't quite tell what. It keeps on telling me that I should install cython although it is already installed. So fingers crossed and full transparency that I did not manage to test those out.

[asvetlov]

Fixed by #3905