Fix Backmerge PR action

[iangmaia]

What does it do?

We have noticed the error below while creating a backmerge to a hotfix branch:

Error creating backmerge pull request: git '--git-dir=<...>/.git' '--work-tree=/<...>' '-c' 'core.quotePath=true' '-c' 'color.ui=false' 'rev-parse' 'release/<HOTFIX VERSION>'  2>&1
status: pid 11499 exit 128
output: "fatal: ambiguous argument 'release/<HOTFIX VERSION>': unknown revision or path not in the working tree.\nUse '--' to separate paths from revisions, like this:\n'git <command> [<revision>...] -- [<file>...]'\nrelease/<HOTFIX VERSION>

Meaning that the given branch release/<HOTFIX VERSION> isn't present locally and only in origin. From inspecting the code and logs, this error most likely happened in the method GitHelper.point_to_same_commit?, called in the line 106 of the action create_release_backmerge_pull_request_action.

This PRs uses origin/ to compare the refs and some safety net to point_to_same_commit?.

Checklist before requesting a review

• Run bundle exec rubocop to test for code style violations and recommendations
• Add Unit Tests (aka specs/*_spec.rb) if applicable
• Run bundle exec rspec to run the whole test suite and ensure all your tests pass
• Make sure you added an entry in the CHANGELOG.md file to describe your changes under the appropriate existing ### subsection of the existing ## Trunk section.
• If applicable, add an entry in the MIGRATION.md file to describe how the changes will affect the migration from the previous major version and what the clients will need to change and consider.

[dangermattic]

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[AliSoftware]

Would be worth testing this in real world in a dummy repo (maybe release-toolkit-demo, which was created a while ago mostly for such testing purposes…?), e.g. creating a release/12.4 branch and a release/12.3 branch then running that action with source_branch:'release/12.3' and no target_branches)

[iangmaia]

@AliSoftware

Would be worth testing this in real world in a dummy repo (maybe release-toolkit-demo, which was created a while ago mostly for such testing purposes…?), e.g. creating a release/12.4 branch and a release/12.3 branch then running that action with source_branch:'release/12.3' and no target_branches)

I've ran some tests, and unfortunately, fetching origin didn't really fix the issue, so we had to use origin/ when comparing refs. I've updated the code on 332e9f8, and this worked fine. I've also removed the origin fetch (17eb938) as it seems redundant in the end.

[mokagio]

What do you think of:

Suggested change

	puts "Error: #{e.message}"
	UI.error "Error fetching commits for #{ref1} and #{ref2}: #{e.message}"

Actually, those are two different suggestions:

• Use UI.error instead of puts
• Include the attempted operation in the error message

[mokagio]

Unrelated to this particular line, but I wonder if it would be worth adding a test to ensure that if we pass branches that already have "origin/" in the name, our logic doesn't append an additional "origin/" to them.

[mokagio]

@iangmaia I'll take over merging this already approved PR so that I can update the changelog etc. of my removal PR #580 on top of this. Thanks!