Trigger a merged build per pipeline rather than step

[zsims]

If the build pipeline has multiple steps, then multiple merge builds will be triggered. There should be only merged build triggered.

[flexportnes]

I'm interested in using this plugin over our home-grown solution, however we would need this functionality before switching. We currently pin the commit that will be merged into the PR as an artifact/metadata so that there's a consistent merge for all of the different steps, even if new commits are added to the target branch.

[zsims]

The plugin can do what's in this bug, it's just about avoiding duplicate builds on:

steps:
  - label: 'Make something'
    commands:
      - make something
    plugins:
      - seek-oss/github-merged-pr#v1.0.1:
          mode: trigger

  - label: 'Make something else'
    commands:
      - make something-else
    plugins:
      - seek-oss/github-merged-pr#v1.0.1:
          mode: trigger

The idea was to set metadata to make sure it's only triggered once. Regardless if you have multiple steps. Is that what you're after?

[flexportnes]

Not really-- our issue comes from if you have steps that don't start for a while in a build, or if you retry a step, you can get into a state where the merge ref from master isn't the same across all steps since each step performs the merge into the pr branch independently.

Maybe I'm misunderstanding how it works?