label_testmerge_conflicts.yml

name: 'Testmerge Conflict Detection'

on:
  push:
    branches:
      - testmerge
  pull_request_target:
    types: [ready_for_review, opened, synchronize, reopened]

jobs:
  triage:
    runs-on: ubuntu-latest
    steps:
      - name: Git checkout
        uses: actions/checkout@v4
        with:
          token: ${{ secrets.GITHUB_TOKEN }}
          fetch-depth: 0
          ref: testmerge
      - name: Check for testmerge conflicts
        id: check
        run: |
          git config --local user.email "action@github.com"
          git config --local user.name "Testmerge Conflict Detection"
          git fetch origin pull/${{ github.event.number }}/head:PR${{ github.event.number }}
          git merge --no-commit --no-ff PR${{ github.event.number }} || true
          CONFLICTS=$(git ls-files -u | wc -l)
          if [ "$CONFLICTS" -gt 0 ] ; then
            echo "There is a merge conflict. Aborting"
            git merge --abort
            echo "success=0" >> $GITHUB_OUTPUT
            exit 0
          fi
          echo "success=1" >> $GITHUB_OUTPUT
      - name: Label PR
        uses: jburgess/AddRemovePrLabels@v1.0.4
        if: steps.check.outputs.success == 0
        with:
          githubToken: '${{ secrets.GITHUB_TOKEN }}'
          labelsToAdd: 'Testmerge Conflict'
      - name: Unlabel PR
        uses: jburgess/AddRemovePrLabels@v1.0.4
        if: steps.check.outputs.success == 1
        with:
          githubToken: '${{ secrets.GITHUB_TOKEN }}'
          labelsToRemove: 'Testmerge Conflict'