Release 0.900 planning

[JukkaL]

I'm planning to release mypy 0.900 some time in March. This release will have a particularly significant change, as third-party stubs are no longer shipped with mypy. They need to be installed by installing suitable stub packages. For example, pip install types-requests installs the stubs for Requests. Mypy will suggest the names of stub packages to install, and mypy --install-types will automatically install the suggested stub packages (this doesn't work with the mypy daemon, however).

Since this change is potentially quite disruptive, I'm announcing the release here well ahead of the target release date.

The unbundling of typeshed is already implemented in GitHub master, so it's possible to start testing this right now. If you can, please try using a development version and report how it went. You can find pre-built wheels here:

https://github.com/mypyc/mypy_mypyc-wheels/releases

I'll probably cut the release branch around mid-March (but this is still very tentative).

[hauntsaninja]

List of potential issues to discuss pre-release:

• --ignore-missing-imports not working for modularized typeshed types #10283
• Use native SupportsIndex in builtins typeshed#5229 (comment)

[TheCleric]

@JukkaL do we have a different timeframe for this now?

[JukkaL]

Sorry, things got delayed. Now it looks that we could have the release around Jun 4 to Jun 7.

It would be nice to fix these issues before the release:

• --ignore-missing-imports not working for modularized typeshed types #10283 (--ignore-missing-imports and modular typeshed)
• Limit the number of generated errors if stubs are missing #10529 (limit number of errors generated from missing stubs)

Please let me know if you can help with one of the above. Otherwise I'll look at fixing them.

[TheCleric]

I'll see if I can tackle #10283 . I'll post there if I have any questions.

[JukkaL]

I'd like to also address #10538 (document security implications of --install-types).

[TheCleric]

@JukkaL PR for #10283: #10546

[TheCleric]

@JukkaL PR for #10538 : #10555

Also I added a comment on #10529 because I tried to take a look at it, but am not sure if I'm understanding it correctly.

[JukkaL]

I think that all release blockers have now been addressed in master. I'll prepare the release branch on Monday. I'll probably cut the branch from a commit that is around 1-2 weeks old, and cherry-pick fixes that address release blockers or that seem low-risk. We've been testing 58aef05 internally at Dropbox.

My current estimate for the date of the release is Tue 8 Jun.

[JukkaL]

The release is now out: https://mypy-lang.blogspot.com/2021/06/mypy-0900-released.html

Thanks to everyone who helped with the release! This was a big one.

[JukkaL]

I uploaded mypy 0.901 that fixes mypy --install-types with binary wheels (#10596).

[JukkaL]

I uploaded mypy 0.902 that fixes a few more issues related to --install-types and stub packages.