action.yml

name: Get PR Number
description: Get PR number for mergue queues and squash merges
branding:
  icon: package
  color: blue

inputs:
  ### Required
  # Nothing!

  ### Typical / recommended
  # Nothing!

  ### Usually a bad idea / not recommended
  token:
    description: Specify token (GH or PAT), instead of inheriting one from the calling workflow
    default: ${{ github.token }}

outputs:
  pr:
    description: 'Associated pull request number'
    value: ${{ steps.vars.outputs.pr }}

runs:
  using: composite
  steps:
    # Process variables and inputs
    - uses: actions/checkout@v4
    - id: vars
      shell: bash
      run: |
        # Get PR number (pull_request, merge_group or push)
        if [ ${{ github.event_name }} == 'pull_request' ]
        then
          echo "Event type: pull request"
          pr=${{ github.event.number }}
        elif [ ${{ github.event_name }} == 'merge_group' ]
        then
          echo "Event type: merge queue"
          pr=$(echo ${{ github.event.merge_group.head_ref }} | grep -Eo "queue/main/pr-[0-9]+" | cut -d '-' -f2)
        elif [ ${{ github.event_name }} == 'push' ]
        then
          echo "Event type: push"
          pr=$(\
            curl -sL -H "Accept: application/vnd.github+json" -H "Authorization: Bearer ${{ inputs.token }}" \
              -H "X-GitHub-Api-Version: 2022-11-28" \
              https://api.github.com/repos/${{ github.repository }}/commits/${{ github.event.after }}/pulls \
                | jq .[0].number
          )
        elif [ ${{ github.event_name }} == 'release' ]
        then
          echo "Event type: release"
          pr=$(\
            curl -sL -H "Accept: application/vnd.github+json" -H "Authorization: Bearer ${{ inputs.token }}" \
              -H "X-GitHub-Api-Version: 2022-11-28" \
              https://api.github.com/search/issues\?q\=repo:${{ github.repository }}+is:pr+is:merged \
                | jq .items[0].number
          )

          if [ -z "${pr}" ]
          then
            echo "No PR number found. Was this push triggered by a squashed PR merge?"
            pr=""
          fi
        else
          echo "Event type: unknown or unexpected"
        fi

        # Validate PR number
        if [[ ! "${pr}" =~ ^[0-9]+$ ]]; then
          echo "PR number format incorrect: ${pr}"
          exit 1
        fi

        # Output PR number
        echo "Summary ---"
        echo -e "\tPR: ${pr}"
        echo "pr=${pr}" >> $GITHUB_OUTPUT