auto-merge.yml

name: Auto-merge
on:
  pull_request_target:
    types: ready_for_review
  workflow_call:
    inputs:
      pr:
        description: "Pull Request number"
        type: number
        required: true
      url:
        description: "Pull Request URL (HTML, not API)"
        type: string
        required: false

permissions:
  contents: write
  pull-requests: write

jobs:
  approve:
    continue-on-error: true
    runs-on: ubuntu-latest
    if: ${{ github.actor_id == github.repository_owner_id || inputs.pr }}
    env:
      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
    steps:
      - name: count requested reviewers
        id: reviewers
        run: |
          REVIEWERS_NUM=$(echo $REQUESTED_REVIEWERS | jq '. | length')
          echo "value=$REVIEWERS_NUM" >> "$GITHUB_OUTPUT"
        env:
          REQUESTED_REVIEWERS: ${{ toJson(github.event.pull_request.requested_reviewers) }}

      - name: Linked issues
        id: issues
        run: |
          QUERY='query ($prNumber: Int!, $repositoryName: String!, $repositoryOwner: String!) {
            repository(name: $repositoryName, owner: $repositoryOwner) {
              pullRequest(number: $prNumber) {
                closingIssuesReferences(first: 10) {
                  nodes {
                    number
                  }
                }
              }
            }
          }'

          ISSUES=$(gh api graphql -f query="$QUERY" -F prNumber=${{ github.event.pull_request.number || inputs.pr }} -F repositoryName=${{ github.event.repository.name }} -F repositoryOwner=${{ github.event.repository.owner.login }} -q '.data.repository.pullRequest.closingIssuesReferences.nodes[] | .number')

          echo "num=$ISSUES" >> "$GITHUB_OUTPUT"
          if [ -z "$ISSUES" ]
          then
            echo "No issues linked to this PR."
            echo "have=false" >> "$GITHUB_OUTPUT"
          else
            echo "Issue(s) linked: $ISSUES"
            echo "have=true" >> "$GITHUB_OUTPUT"
          fi
      # better criteria is "is this PR have only one issue and it authored by author of this PR?"

      - name: Approve
        # if there is no requested reviewers specified  and  PR don't have any linked issue's:
        if: success() && steps.reviewers.outputs.value == '0'
        run: gh pr review --approve "${{ github.event.pull_request.html_url || inputs.url || inputs.pr }}"

      - name: Auto-merge
        # only if no linked issue:
        if: success() && steps.reviewers.outputs.value == '0' && steps.issues.outputs.have != 'true'
        run: >-
          gh pr merge --auto
          --${{ github.event.pull_request.commits > 1 && 'squash' || 'merge' }}
          "${{ github.event.pull_request.html_url || inputs.url || inputs.pr }}"