Drop support for 32-bit platforms?

[JukkaL]

32-bit platforms seem pretty much obsolete (outside of embedded, which we don't actively support). There is no 32-bit version of Windows 11, and Windows 10 will reach EOL soon. All new desktop processors have been 64-bit for well over a decade now.

Does anybody have evidence that a non-trivial number of users are still using 32-bit platforms?

If we decide to move forward with this, we can start with not running CI on 32-bit platforms and updating documentation to not say that 32-bit platforms are supported (not sure if we ever make this explicit).

We can still keep the existing level of support in mypyc, in case somebody wants to maintain it in the future. If at some point there hasn't been any interest in fixing issues on 32-bit platforms for 6 months, we can think about removing all existing support.

[sterliakov]

How much effort is needed in mypy (not mypyc) to keep supporting 32 bit? We still have remnants of python 2 support (such as lambda tuple unpacking support), but I don't remember any place outside of mypyc dependent on platform architecture. If the necessary support is really limited to running one more CI job on 32 bit, is it worth dropping at all?

[Newbytee]

Many Linux distributions still build 32-bit packages, especially for ARM. Also, some modern Android phones ship with 32-bit OS:es despite that the hardware is 64-bit, though I don't know how relevant this is for mypy. Maybe slightly more relevant for mypyc.

[JukkaL]

Supporting 32-bit platforms in mypy (when not compiled) doesn't take any effort, as long as CPython and GitHub Actions maintain 32-bit support. My main concern is mypyc, since it's fairly common that PRs require some work specific to 32-bit platforms.

One option would be to only run mypy tests (i.e no mypyc tests) on 32-bit platforms, but keep 32-bit support in mypyc around as a best-effort thing -- we'll accept PRs that fix mypyc issues on 32-bit platforms, but we won't promise to fix them ourselves.

[ilevkivskyi]

Yeah, supporting 32-bit on best effort basis sounds good.

[JukkaL]

It looks like only using 64-bit platforms in CI and supporting 32-bit platforms on a best effort basis is the best compromise.