`StreamReaderProtocol` was a public API from Python 3.4 to 3.6:

- https://docs.python.org/3.4/library/asyncio-stream.html?highlight=streamreaderprotocol#streamreaderprotocol
- https://docs.python.org/3.5/library/asyncio-stream.html?highlight=streamreaderprotocol#streamreaderprotocol
- https://docs.python.org/3.6/library/asyncio-stream.html?highlight=streamreaderprotocol#streamreaderprotocol

In Python 3.7, it vanished from the documentation. I couldn't find which commit made that change and why.

- https://docs.python.org/3.7/search.html?q=streamreaderprotocol&check_keywords=yes&area=default

Apparently it's deprecated in Python 3.8 as a side effect of https://bugs.python.org/issue36889.

Unfortunately, that ticket says nothing about `StreamReaderProtocol` and how to replace it. The documentation added when fixing that ticket doesn't say anything about `StreamReaderProtocol` either.

It would be less difficult to swallow the rate of API churn in asyncio if there were at least a few words about why it's happening and what concrete benefits it brings to users.

I can understand the need to change APIs, even public APIs. However, when there's zero information in tickets, commit messages and documentations, I don't know why change is happening and how I'm supposed to adapt my code. That's stressful. If what I'm doing is deprecated, probably it's a bad idea, but I can't know why?

I'm sure you aren't trying to convince me to avoid stream utilities in asyncio and write my own buffering. However, that's the result you're getting :-/ Providing a quick explanation of deprecations / removals of public APIs would help.

(Somewhat related: https://bugs.python.org/issue24885)