Description

mhsmith

opened on Oct 5, 2025

Issue body actions

Bug report

Bug description:

This was discovered in #131882 (comment), which involved a configure check that used a header file. The PR changed the header file, but not the configure script. So the build reused a config.cache file from a different branch (probably main), the check wasn't rerun, and the fact that the change broke the build wasn't discovered until much later.

Because the configure script could depend on anything in the repository, I don't think there's any way to make this safe, not even within the scope of a single PR. So I suggest removing the cache action from the workflow.

This is a separate thing from ccache, which is still safe as far as I know.

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

Linked PRs

• GH-139596: Cease caching config.cache & ccache in GH Actions #139623
• [3.14] GH-139596: Cease caching config.cache & ccache in GH Actions #141429
• gh-139596: Cease caching config.cache & ccache in GH Actions #141451
• [3.13] GH-139596: Cease caching config.cache & ccache in GH Actions (GH-141429) #141569

Activity

1. mhsmith

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   buildThe build process and cross-buildThe build process and cross-build

   on Oct 5, 2025
2. picnixz

   added

   infraCI, GitHub Actions, buildbots, Dependabot, etc.CI, GitHub Actions, buildbots, Dependabot, etc.

   on Oct 5, 2025
3. gpshead

   added 2 commits that reference this issue on Nov 11, 2025

   GH-139596: Cease caching config.cache & ccache in GH Actions (GH-139623)

   c744ccb

   [3.14] pythonGH-139596: Cease caching config.cache & ccache in GH Act…

   ce5c716
4. gpshead commented on Nov 11, 2025

   

   gpshead

   on Nov 11, 2025

   Member

   More actions

   thanks! fixed on main - manual backport to 3.14 created as the yml files had changed enough, it could use review.
5. hugovk

   added 4 commits that reference this issue on Nov 14, 2025

   gh-139596: Cease caching config.cache & ccache in GH Actions (#141451)

   181a2f4

   pythongh-139596: Cease caching config.cache & ccache in GH Actions (p…

   aec35cc

   [3.14] GH-139596: Cease caching config.cache & ccache in GH Actions (#…

   a2442fd

   [3.13] pythonGH-139596: Cease caching config.cache & ccache in GH Act…

   7c80b6a
6. gpshead

   added a commit that references this issue on Nov 14, 2025

   [3.13] GH-139596: Cease caching config.cache & ccache in GH Actions (G…

   76db223
7. gpshead commented on Nov 14, 2025

   

   gpshead

   on Nov 14, 2025

   Member

   More actions

   thanks!
8. gpshead

   closed this as completedon Nov 14, 2025
9. StanFromIreland

   added 2 commits that reference this issue on Dec 6, 2025

   pythonGH-139596: Cease caching config.cache & ccache in GH Actions (p…

   8a2cb87

   pythongh-139596: Cease caching config.cache & ccache in GH Actions (p…

   206ec31

Issue actions