gh-85283: _stat extension uses the limited C API

[vstinner]

The _stat C extension is now built with the limited C API.

• Issue: [C API] Convert a few stdlib extensions to the limited C API (PEP 384) #85283

[vstinner]

I moved the Changelog entry to the Build category, and I documented the change in the Build Changes of What's New in Python 3.13. See #85283 (comment) about the choice of the Category.

Hm, I'm not so sure about not building _stat if Py_TRACE_REFS are defined

[vstinner]

Hm, I'm not so sure about not building _stat if Py_TRACE_REFS are defined

It's a workaround for issue #108634: without this change, building Python with ./configure --with-trace-refs fails on this PR.

But. It's more complicated than expect: multiple tests fail when _stat extension is missing. See issue #108638.

I'm going to:

• Merge this PR: build _stat with Py_LIMITED_API
• Break TraceRefs buildbot for now
• maybe: Fix tests with _stat is missing, issue Test suite expects _stat extension to be available #108638
• maybe: don't build _stat on TraceRefs (to workaround Py_LIMITED_API issue)
• or: fix TraceRefs for Py_LIMITED_API, issue Py_TRACE_REFS is not compatible with Py_LIMITED_API #108634

[AA-Turner]

• Merge this PR: build _stat with Py_LIMITED_API
• Break TraceRefs buildbot for now

Just to note a slight hesitation of intentionally breaking a buildbot &c, given that _stat works currently, and building with the limited C API is a "nice to have" rather than critical/urgent. Would it be better to fix test assumptions you referenced first, then revisit this PR?

A

[vstinner]

or: fix TraceRefs for Py_LIMITED_API, issue #108634

I wrote PR #108663 which makes Py_TRACE_REFS build compatible with the limited C API.

[serhiy-storchaka]

Caught a bug! PyModule_Add requires 3.13.

[vstinner]

Caught a bug! PyModule_Add requires 3.13.

Oh! Only on Windows, so I didn't notice locally on Linux.

I don't want to downgrade _stat.c by avoid the new nice PyModule_Add() just to set Py_LIMITED_API to the oldest Python version. There is no benefits here, since _stat is shipped with Python itself. Well, the only benefit would be to test the limited C API itself. But here, I prefer to stick to PyModule_Add(). So I reverted the Py_LIMITED_API version to 3.13.

[vstinner]

Break TraceRefs buildbot for now

This PR will no longer break TraceRefs. I merged PR #108663 which adds limited C API support to Py_TRACE_REFS build.

[vstinner]

I rebased my PR to solve a merge conflict (Doc/whatsnew/3.13.rst).

[vstinner]

@erlend-aasland: Would you mind to review the latest version of the PR?

[vstinner]

On-going discussion about converting some stdlib C extensions to the limited C API: https://discuss.python.org/t/use-the-limited-c-api-for-some-of-our-stdlib-c-extensions/32465

[erlend-aasland]

@erlend-aasland: Would you mind to review the latest version of the PR?

Sorry, I prefer to still stay out of the C API discussions. From the linked discussion, it seems to me these changes are far from non-controversial; perhaps considered marking this as draft until consensus have been reached.

[vstinner]

Ok, I marked my PR as a draft. I already marked the 3 other similar PRs as draft.

[vstinner]

I close this PR until a decision is taken on using the limited C API for a few Python stdlib extensions. Well, it's not that complicated to rewrite this PR (or reuse the patch of the closed PR).