action.yaml

name: 'Validate version labels'
description: 'Checks that a PR has a valid version bump label'
inputs:
  LABELS:
    description: 'The labels from the PR, or provided by the user in a manual run. Only the version bump label is required, but if you choose to provide others, the format is "LABEL1,LABEL2,LABEL3""'
    required: true
outputs:
  VERSION_INSTRUCTION:
    description: "Which of 'patch', 'minor', or 'major' to pass to npm version, or if we should run npm version at all ('none')."
    value: ${{ steps.get-version-instruction.outputs.VERSION_INSTRUCTION }}
  MESSAGE:
    description: 'The message to pass to the PR comment if this job fails. If this job succeeds, this output is empty.'
    value: ${{ steps.get-version-instruction.outputs.MESSAGE }}
  JOB_ID:
    description: 'The ID of the job calling this action. Used to print a link in the PR comment.'
    value: ${{ steps.get-version-instruction.outputs.JOB_ID }}

runs:
  using: 'composite'
  steps:
    - id: get-version-instruction
      run: |
        shopt -s nocasematch
        echo "JOB_ID=${{ github.job }}" >> $GITHUB_OUTPUT
        LABELS=${{ inputs.LABELS }}

        # Do a regex search for version bump labels. This loads the BASH_REMATCH array with the matches so we can ensure there is only one.
        echo "Searching labels for version bump: $LABELS"
        if !  [[ $LABELS =~ (major|minor|patch|none|version-bump) ]]; then
          MESSAGE="No labels present on the PR, expected version bump label (one of 'major', 'minor', 'patch', or 'none')"
          echo "MESSAGE=$MESSAGE" >> $GITHUB_OUTPUT        
          exit 1
        elif [[ ${#BASH_REMATCH[@]} > 2 ]]; then #BASH_REMATCH[0] is the full match, BASH_REMATCH[1] is the first capture group, so >2 means there were more than one capture groups
          MESSAGE="Multiple version bump labels present on the PR, expected only one of 'major', 'minor', 'patch', or 'none'"
          echo "MESSAGE=$MESSAGE" >> $GITHUB_OUTPUT
          exit 1
        fi

        LABEL=${BASH_REMATCH[1]}
        echo "Version bump label found: $LABEL"
        echo "VERSION_INSTRUCTION=$LABEL" >> $GITHUB_OUTPUT
        echo "JOB_ID=${{ github.job}}" >> $GITHUB_OUTPUT
      shell: bash