Typeshed regression in 0.940

[offbyone]

Bug Report

Typeshed had an issue with message.pyi that was identified in python/typeshed#7019:

typeshed/stdlib/email/message.pyi:13: error: Cannot determine type of "Any" (diff)

This was resolved in python/typeshed#7022 on Jan 24, sometime after the mypy 0.931 tag was cut.

mypy 0.940 apparently has the broken commit in typeshed, though. When running our regular CI tests, we picked up the 0.940 upgrade to mypy, which started failing our type checks by adding that additional output. You can see the pre- and post- upgrade tests here:

• hamcrest before, on 0.931: https://github.com/hamcrest/PyHamcrest/runs/5483300612?check_suite_focus=true
• hamcrest after, on 0.940: https://github.com/hamcrest/PyHamcrest/runs/5522914347?check_suite_focus=true

Your Environment

• Mypy version used: 0.940
• Mypy command-line flags: n/a
• Mypy configuration options from mypy.ini (and other config files): n/a
• Python version used: Observed on 3.8.12 and 3.10.0, but github stop tests after some fail in a group, so probably all 3.8+
• Operating system and version: Ubuntu and macOS

[Tinche]

This is also breaking the attrs test suite. Any chance this could be hotfixed? Feels kinda bad to tweak our test suite to account for this :(

[JelleZijlstra]

cc @JukkaL, maybe we can cherry-pick #12340 and do a hotfix?

[JukkaL]

@JelleZijlstra I'll do a 0.941 release with #12340.

[JukkaL]

Mypy 0.941 is now out with the fix (#12340).

[Tinche]

@JelleZijlstra @JukkaL thank you kindly for the quick response!