Make CI run checkout PR for backlogger_preview

[b10n1k]

Switch trigger to pull_request_target and adjust the checkout actions
to run against the latest code in the PR.
Although it works for backlogger, it might impact when the workflow
run in another repository.

https://progress.opensuse.org/issues/158236

[github-actions]

PR Preview Action v1.4.7
Preview removed because the pull request was closed.
2024-04-29 10:51 UTC

[perlpunk]

Note that this action is not a workflow like the ones under .github/workflows. It provides an action that can be used from other repositories' workflows.
It needs to do a checkout into a different directory.
I don't know right now how to solve the problem, but this won't work.

[kalikiana]

I would guess ref: ${{ github.event.pull_request.head.sha }} is needed here. Unfortunately GitHub docs don't seem to explain this case?

Someone on stackoverflow suggests github.event.workflow_run.head_sha would work without giving an explanation. And maybe fetch-depth: 2 is needed?

I'm thinking out loud here since that's what I had to look up myself

[b10n1k]

seems to work now but not sure how affects https://github.com/os-autoinst/qa-tools-backlog-assistant/blob/master/.github/workflows/backlog_checker.yml#L21

[perlpunk]

I wonder if this can work because the main purpose of the action is to run on the main branch, so there is no github.event.pull_request.head.sha.
I think it should be possible to push this on your fork's main branch and try it out for real, before we merge and have to revert.
Also, I'm wondering if the preview was actually working before...

[b10n1k]

I wonder if this can work because the main purpose of the action is to run on the main branch, so there is no github.event.pull_request.head.sha. I think it should be possible to push this on your fork's main branch and try it out for real, before we merge and have to revert. Also, I'm wondering if the preview was actually working before...

i found it hard to run it from my repository. CI fails.

[okurz]

I see "TEST" on https://opensuse.github.io/backlogger/pr-preview/pr-42/ so I guess this works :)

[b10n1k]

I see "TEST" on https://opensuse.github.io/backlogger/pr-preview/pr-42/ so I guess this works :)

it does but i need to understand the I wonder if this can work because the main purpose of the action is to run on the main branch, so there is no github.event.pull_request.head.sha.

[b10n1k]

testing it with @kalikiana we verified it works. we think to merge and see how it will go

I checked with Yannis that the TEST change works, and this should address the review remarks

[kalikiana]

For reference, this is what it looked like with the TEST change, and after undoing https://github.com/openSUSE/backlogger/compare/3b1dcdee76c956d502539fae68d0528da7a1dc3d..83751c86485e6bfb8dd2b6748ab12add7288e22d which didn't work. I mention it since the proof is a moving target.

[kalikiana]

Well, something here is fishy. The preview did not change after the TEST change got removed.

[kalikiana]

Hum. Now I do see the update. Is there a delay we need to take into account? And which makes debugging this very confusing?