SocketStream.receive sometimes returns bytearray objects on Windows

[jonathanslenders]

Things to check first

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

AnyIO version

4.4.0

Python version

3.11

What happened?

StreamProtocol, here: https://github.com/agronholm/anyio/blob/master/src/anyio/_backends/_asyncio.py#L1075
incorrectly assumes that it will only get bytes objects as an argument. Unfortunately, on Windows, that's not the case. For the ProactorEventLoop, we'll get bytearray objects here.

See:

• asyncio.Protocol.data_received should also accept bytearray alongside bytes python/typeshed#12606
• asyncio.BaseProactorEventLoop feeds bytearray objects to the Protocol.data_received callback, contradicting docs python/cpython#123496

I think the quickest fix for anyio is to accept bytearray as well, and convert it into bytes, regardless of what typeshed/cpython do.

How can we reproduce the bug?

(Sorry, I don't have access to a Windows machine right now to create an example, but please let me know if an example script is needed.)

[jonathanslenders]

It looks like it was fixed in cpython v3.12.0a4 thanks to this commit:
python/cpython@1bb68ba

However, it would still be good to handle the issue here for Python 3.10 and 3.11. (3.9 doesn't have the issue).

[agronholm]

Review welcome. As I mentioned in the CPython issue, I was able to locally reproduce this even on the latest 3.12 release.