aio-libs / multidict / 37838988742

86%

master: 86%

push

github

Build without -Wconversion on GCC 9 (#1760)

<!-- Thank you for your contribution! -->

## What do these changes do?

The re-tagged `v7.1.0` run got past the cp310 and cp311 armv7l wheels
after #1759, then failed on cp312: GCC 9, which the
`manylinux_2_31_armv7l` image ships, flags `_PyLong_CompactValue()` in
CPython's own `cpython/longintrepr.h` under `-Wsign-conversion`, and
`-Werror` makes that fatal. It is not specific to 32-bit or ARM: GCC 9
on x86_64 fails the same way for every CPython from 3.12 on, so building
the sdist with Ubuntu 20.04's default compiler would break too. GCC 10,
11 and 12 are clean.

`setup.py` now asks the configured compiler for its predefined macros
and drops `-Wconversion` when it is GCC older than 10. Clang, MSVC and a
compiler that cannot be probed keep the flags unchanged, so CI still
builds with `-Wconversion` everywhere it did.

The changelog entry goes into the unpublished 7.1.0 section next to the
#1759 one, since the tag gets moved to this merge commit.

## Are there changes in behavior for the user?

No; the C extension builds again with GCC 9.

## Is it a substantial burden for the maintainers to support this?

No; the check can go once GCC 9 stops mattering.

## Related issue number

Follow-up to #1759. Failed run:
https://github.com/aio-libs/multidict/actions/runs/37833640970

## Checklist

- [x] I think the code is well written
- [ ] Unit tests for the changes exist N/A, build fix; verified with GCC
9 builds as described below
- [x] Documentation reflects the changes
- [ ] If you provide code modification, please add yourself to
`CONTRIBUTORS.txt` N/A
- [ ] Add a new news fragment into the `CHANGES/` folder N/A, the entry
is added to the unreleased 7.1.0 section of `CHANGES.rst` directly
- [x] `make doc-spelling` passes and any new technical words are added
to `docs/spelling_wordlist.txt`

Drafted with Claude Code (Claude Opus 5.5); reviewed by @asvetlov.

<details>
<summary>Agent run details (optional, for ... (continued)

832 of 1664 branches covered (50.0%)

Branch coverage included in aggregate %.

9706 of 10588 relevant lines covered (91.67%)

1.83 hits per line