[3.13] gh-141004: Add a CI job ensuring that new C APIs include documentation (GH-142102)

[ZeroIntensity]

(cherry picked from commit 1a7824a)

• Issue: Document the entire C API #141004

[ZeroIntensity]

See #142247 (comment).

[ZeroIntensity]

@hugovk Quick question -- it seems CI on 3.13 uses Python 3.12, not 3.13. Is that intentional? If so, I need to remove the use of _colorize here on 3.13.

[hugovk]

Hmm, well we're installing 3.x in this job, which right now is 3.14:

https://github.com/ZeroIntensity/cpython/blob/backport-1a7824a-3.13/.github/workflows/build.yml#L152-L154

However, for the 3.14 branch, when we run configure:

https://github.com/ZeroIntensity/cpython/blob/93459405c92cb5d275bf310b1d5d1dc43967cfdc/.github/workflows/build.yml#L164

We get:

checking for python3.14... python3.14
checking Python for regen version... Python 3.14.0

But on this 3.13 branch, for some reason we get:

checking for python3.13... no
checking for python3.13... no
checking for python3.12... python3.12
checking Python for regen version... Python 3.12.3

I'm not sure why configure is selecting 3.12...

[ZeroIntensity]

Do you know if the configure script on 3.13 checks for 3.14? I think that might be the problem. I'm guessing that Python 3.12 is already installed on the system the CI job is running on, and actions/setup-python installs 3.14, which isn't detected by the configure script, so it falls back to 3.12.

[hugovk]

Do you know if the configure script on 3.13 checks for 3.14?

No, it only checks the current version and lower.

main:

cpython/configure

Line 3828 in 756e7d1

for ac_prog in python$PACKAGE_VERSION python3.15 python3.14 python3.13 python3.12 python3.11 python3.10 python3 python

3.14:

cpython/configure

Line 3820 in f200776

for ac_prog in python$PACKAGE_VERSION python3.15 python3.14 python3.13 python3.12 python3.11 python3.10 python3 python

3.13:

cpython/configure

Line 3765 in b57d695

for ac_prog in python$PACKAGE_VERSION python3.13 python3.12 python3.11 python3.10 python3 python

I think that might be the problem. I'm guessing that Python 3.12 is already installed on the system the CI job is running on, and actions/setup-python installs 3.14, which isn't detected by the configure script, so it falls back to 3.12.

Yes, that indeed looks like the problem.

Here's a test workflow that installs a give version, then tries to check for them all:

          python3.15 --version --version || true
          python3.14 --version --version || true
          python3.13 --version --version || true
          python3.12 --version --version || true
          python3.11 --version --version || true
          python3.10 --version --version || true

And they all have the given version, plus 3.12. For example with 3.15:

Python 3.15.0a2 (main, Nov 19 2025, 15:10:47) [GCC 13.3.0]
/home/runner/work/_temp/9872e36d-a21e-4c3e-8aa1-e6d8f6781c42.sh: line 2: python3.14: command not found
/home/runner/work/_temp/9872e36d-a21e-4c3e-8aa1-e6d8f6781c42.sh: line 3: python3.13: command not found
Python 3.12.3 (main, Nov  6 2025, 13:44:16) [GCC 13.3.0]
/home/runner/work/_temp/9872e36d-a21e-4c3e-8aa1-e6d8f6781c42.sh: line 5: python3.11: command not found
/home/runner/work/_temp/9872e36d-a21e-4c3e-8aa1-e6d8f6781c42.sh: line 6: python3.10: command not found

And it's an old 3.12.3 baked into the image, because when we specifically ask for 3.12 we get the newest 3.12.12:

/home/runner/work/_temp/5205e491-dc12-4355-bc92-e4fd7a15bf8a.sh: line 1: python3.15: command not found
/home/runner/work/_temp/5205e491-dc12-4355-bc92-e4fd7a15bf8a.sh: line 2: python3.14: command not found
/home/runner/work/_temp/5205e491-dc12-4355-bc92-e4fd7a15bf8a.sh: line 3: python3.13: command not found
Python 3.12.12 (main, Oct 10 2025, 01:01:16) [GCC 13.3.0]
/home/runner/work/_temp/5205e491-dc12-4355-bc92-e4fd7a15bf8a.sh: line 5: python3.11: command not found
/home/runner/work/_temp/5205e491-dc12-4355-bc92-e4fd7a15bf8a.sh: line 6: python3.10: command not found

[ZeroIntensity]

Thanks, I created an issue: #142457