run test only if labels don't contain 'documentation'

[nbiederbeck]

Fix #2226

[nbiederbeck]

Maybe documentation-only or no-pytest-needed would be a better label.

[StFroese]

Maybe relevant:
https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/troubleshooting-required-status-checks#handling-skipped-but-required-checks

[kosack]

I rebased onto the latest main. If this builds, we can merge

[Tobychev]

I gave it another go, tried a different syntax for the conditional to see if that caused the tests to be marked as skipped instead of succeeded as promised by the GitHub docs. I even removed the "documentation" label, which I really tough should ensure the tests are not skipped, but still get get marked as skipped and thus this will be stuck forever.

[Tobychev]

@kosack @nbiederbeck @maxnoe I finally figured out what the problem was: there's a bug/design error in how required steps interact with matrix jobs and the conditional check:
basically if you put the test at the top of a job like the initial PR did, you skip the parent job so the matrix of required jobs aren't even created, and thus they are not marked as skipped, and the requirement checker (or whatever its name is) will wait forever.

I've now implemented one of the two cludges proposed to get around this: put if gates into mostly every substep of the "test" workflow.

[LukasNickel]

Maybe documentation-only or no-pytest-needed would be a better label.

👍 on documentation-only (or any other tag).
I think it is not super clear, that a documentation tag would skip the code checks as a PR might contain changes in documentation and code.

The changes itself look fine to me. It is a bit confusing, that the skipped tests still show up in the list of checks, but its anyway helpful.

[Tobychev]

Changed the magic label to documentation-only and rebased on main to solve the problems with the docs failing to merge.

[Tobychev]

@maxnoe This could finally be merged once the doctests pass, but I don't really understand why they fail. Help!