cache-read-only=true for scheduled workflows on main branch

[kkolman]

The default expression for cache-read-only value is:

${{ github.ref_name != github.event.repository.default_branch }}

But github.event.repository.default_branch is not set by GA on scheduled (cron) workflow runs.
Hence cache-read-only is resolved to true not writing to cache during scheduled runs on the main branch.
For CI configrations where workflows on main line are run via scheduling exclusively (no manual workflow runs happening) cache will never be written to.

I believe this behavior is worth documenting.

Unless there's a solid replacement to github.event.repository.default_branch for obtaining the default branch name (didnt find one in ga contexts).

[AndrzejPw]

@kkolman you are right - that's why I changed value of cache-read-only to:
${{ github.ref != 'refs/heads/develop' }}

And now scheduled runs at least try to write cache. The problem is they are failing with following error:
Save Gradle User Home failed in 'beforeSave': Error: ENOENT: no such file or directory, lstat '/Users/runner/.gradle/caches/7.4.2/kotlin-dsl/scripts/290aeeb3033fad5386fbca5f7db24fe3'

I think it may be related to scheduled workflow runs because when I tested action triggered by PR cache was written successfully.

[bigdaz]

Thanks for the reports. I think we should be able to detect when we are running with a scheduled trigger and avoid setting cache-read-only in this case.

However, I'm having trouble getting a scheduled workflow to execute: I added a ci-schedule.yml workflow and can run it manually via workflow_dispatch, but it never seems to run via the cron trigger. https://github.com/gradle/gradle-build-action/actions/workflows/ci-schedule.yml

Any ideas?

[AndrzejPw]

@bigdaz I see now it is being scheduled :). However, my error with Save Gradle User Home failed in 'beforeSave': Error: ENOENT: no such file or directory, lstat '/Users/runner/.gradle/caches/7.4.2/kotlin-dsl/scripts/290aeeb3033fad5386fbca5f7db24fe3 is not related with scheduled runs. I tested it again and now I have this error everytime cache-read-only is false.

[bigdaz]

@AndrzejPw Can you please raise a separate issue for your problem, since it appears unrelated to this reported issue? If you can provide a link to a failing build that would be great, otherwise the full stack trace would help.

[AndrzejPw]

Thank you - my bug with Save Gradle User Home does not appear anymore (maybe sth was wrong with github environment). If it happens again I will report it.

[bigdaz]

@AndrzejPw FYI there was another report of the ENOENT: no such file or directory from an internal project that allowed me to reproduce, diagnose and fix this issue: #408