This broke when we moved the check-cherry-picks workflow into the bigger
PR workflow. At this time, the "workflow run" became the whole PR
workflow, which includes many more than just 1 job, thus the assumption
in `jobs[0]` doesn't hold anymore.
Most of the checks we do for cherry-picks are dismissable warnings, with
one exception: When a commit hash has been found, but this hash is not
available in any of the pickable branches, we raise this with
severity=error. This should also *block* the merge and not be
dismissable. That's because this is a fixable issue in every case.
Previously, when the diff contained a context line with ```, this would
end the code block and entirely break the markdown rendering.
Now we use the html code blocks provided by `core.summary` and properly
escape the content, so that it never escapes via html tags.
This reduces noise that the cherry-pick reviews produce when formatting
related conflicts had to be resolved. We only do this in the
length-limited review comment, though. All changes, including
whitespace, can still be double-checked in the job log if needed.
This turns the check-cherry-pick script into a github-script based
JavaScript program. This makes it much easier to extend to check reverts
or merge commits later on.
Since all github-scripts need to be written in commonjs, we now default
to it by not setting package.json. Support from editors for .js files is
slightly better than .cjs. To still allow using module imports in the
test runner script, we trick node into loading the script itself as a
module again via `--import ./run`.
This just moves things around to use less specific naming - `labels` is
only *one* script that can potentially be run locally while still being
written in github-script. Later, we can add more.
