tagbot.yml

name: Tagbot
on: [pull_request_target]

concurrency:
  group: "${{ github.workflow }}-${{ github.event.pull_request.number }}"
  cancel-in-progress: true

jobs:
  tagbot:
    # Note: can't rely on github.event.pull_request.merge_commit_sha because pull_request_target
    # does not wait for github mergability check, and the value is outdated.
    # Instead we merge manually in a temporary subdir "pr"
    runs-on: ubuntu-24.04
    permissions:
      pull-requests: write
    steps:
    - name: Checkout base branch for workflow scripts
      uses: actions/checkout@v4

    - name: Checkout PR for computing diff into "pr" subdirectory
      uses: actions/checkout@v4
      with:
        ref: "${{ github.event.pull_request.head.sha }}"
        path: 'pr'
        fetch-depth: 0
        
    - name: Attempt test merge
      id: merge
      run: |
        git config user.name "github-workflow"
        git config user.email "github-workflow@github.com"
        git merge --no-edit --no-ff origin/${{ github.event.pull_request.base.ref }}
      continue-on-error: true
      working-directory: pr

    - name: Abort if merge failed
      if: steps.merge.outcome == 'failure'
      run: |
        echo "Merge conflict detected, failing job."
        exit 1

    - name: set up Python
      uses: actions/setup-python@v5
      with:
        python-version: 3.12

    - name: Get packages
      run: pip install gitpython requests

    - name: Tag and comment
      env:
        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      run: python .github/workflows/tagbot.py