merge.yml

name: Override Merge

on:
  issue_comment:
    types: [created]

jobs:
  merge_comment:
    # Run only if
    # 1. The comment was made on a PR.
    # 2. The comment was made by @samkit-jain.
    # 3. The comment was exactly "/merge" sans the quotes.
    # 4. The PR is open.
    if: |
      github.event.issue.pull_request &&
      github.event.comment.body == '/merge' &&
      !github.event.issue.closed_at &&
      github.event.issue.state == 'open' &&
      github.event.comment.user.login == 'samkit-jain'
    runs-on: ubuntu-latest
    name: Merge PR

    steps:
      - uses: actions/checkout@v2
        with:
          fetch-depth: 0
          token: ${{ secrets.GH_TOKEN }}

      # Get details of the PR. The target and base branch. And also whether the PR can be merged in or not.
      - name: Get PR details
        uses: octokit/request-action@v2.x
        id: get-pr-details
        with:
          route: GET /repos/{repository}/pulls/{pull_number}
          repository: ${{ github.repository }}
          pull_number: ${{ github.event.issue.number }}
        env:
          GITHUB_TOKEN: ${{ secrets.GH_TOKEN }}

      # Merge (rebase) the PR if it is allowed.
      - name: Merge the PR
        id: merge-status
        shell: bash
        env:
          MERGEABLE_STATUS: ${{ fromJson(steps.get-pr-details.outputs.data).mergeable_state }}
          BASE_BRANCH: ${{ fromJson(steps.get-pr-details.outputs.data).base.ref }}
          HEAD_BRANCH: ${{ fromJson(steps.get-pr-details.outputs.data).head.ref }}
        run: |
          if [ "$MERGEABLE_STATUS" = "clean" ]; then
            git config --global user.email "<>"
            git config --global user.name "GitHub Actions"
            git checkout $HEAD_BRANCH
            git pull origin $HEAD_BRANCH
            git checkout $BASE_BRANCH
            git pull origin $BASE_BRANCH
            git rebase $HEAD_BRANCH
            git push origin $BASE_BRANCH
            echo "::set-output name=message::'PR merged in succesfully.'"
          else
            echo "::set-output name=message::'PR cannot be merged in.'"
          fi

      # Post a success/failure comment to the PR.
      - name: Add comment to PR
        uses: octokit/request-action@v2.x
        with:
          route: POST /repos/{repository}/issues/{issue_number}/comments
          repository: ${{ github.repository }}
          issue_number: ${{ github.event.issue.number }}
          body: ${{ steps.merge-status.outputs.message }}
        env:
          GITHUB_TOKEN: ${{ secrets.GH_TOKEN }}

      # Post a failure message when any of the previous steps fail.
      - name: Add failure comment to PR
        if: ${{ failure() }}
        uses: octokit/request-action@v2.x
        with:
          route: POST /repos/{repository}/issues/{issue_number}/comments
          repository: ${{ github.repository }}
          issue_number: ${{ github.event.issue.number }}
          body: PR cannot be merged in. Check the Actions execution tab for details.
        env:
          GITHUB_TOKEN: ${{ secrets.GH_TOKEN }}