sync_branches.yml

name: Sync Branches
on:
  push:
    branches:
      - "2.4"
      - "2.5"
  workflow_dispatch:

permissions: {}

jobs:
  sync-branches:
    strategy:
      matrix:
        include:
          - from_branch: "2.4"
            to_branch: "2.5"
          - from_branch: "2.5"
            to_branch: "main"
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write
    env:
      SYNC_COMMITTER: github-actions[bot]
    steps:
      - name: "Check out repository"
        uses: actions/checkout@v4.1.7
        with:
          persist-credentials: true

      - name: "Configure Git"
        run: |
          git config --global merge.ours.driver true
          git config --global pull.rebase false

      - name: "Check if merge branch already exists"
        id: check_sync
        run: |
          if git fetch origin "${SYNC_BRANCH}"; then
            echo "Branch ${SYNC_BRANCH} already exists, checking if the branch was modified..."
            COMMITTER="$(git show --pretty=format:"%cn <%ce>" --no-patch "origin/${SYNC_BRANCH}")"
            if [ "${COMMITTER}" = "${SYNC_COMMITTER}" ]; then
              echo "Branch ${SYNC_BRANCH} was not modified."
            else
              echo "Branch ${SYNC_BRANCH} was modified, either delete it or update it yourself."
              echo "skip_sync=true" >> $GITHUB_OUTPUT
            fi
          else
            echo "Branch ${SYNC_BRANCH} does not exist yet."
          fi
        env:
          SYNC_BRANCH: sync-branch-${{ matrix.from_branch}}-to-${{ matrix.to_branch }}

      - name: "Merge Changes"
        if: steps.check_sync.outputs.skip_sync != 'true'
        run: |
          git checkout -b "${SYNC_BRANCH}"
          git fetch origin "${TO_BRANCH}"
          git reset --hard "origin/${TO_BRANCH}"
          git pull --no-edit origin "${FROM_BRANCH}"
          COMMIT_ORIGINAL="$(git show --no-patch --format="%h" "origin/${TO_BRANCH}")"
          COMMIT_MERGE="$(git show --no-patch --format="%h" "origin/${TO_BRANCH}")"
          if [ "${COMMIT_ORIGINAL}" = "${COMMIT_MERGE}" ]; then
            git status
            echo "No changes (or merge conflict), skipping push and PR creation."
          else
            git push --force origin "${SYNC_BRANCH}"
            gh pr create -B "${FROM_BRANCH}" -H "${SYNC_BRANCH}" --title "${PULL_REQUEST_TITLE}" --body "${PULL_REQUEST_BODY}" --labels "sync-branches"
          fi
        env:
          FROM_BRANCH: ${{ matrix.from_branch}}
          TO_BRANCH: ${{ matrix.to_branch }}
          SYNC_BRANCH: sync-branch-${{ matrix.from_branch}}-to-${{ matrix.to_branch }}
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PULL_REQUEST_TITLE: Merge changes from `${{ matrix.from_branch }}` into `${{ matrix.to_branch }}`
          PULL_REQUEST_BODY: |
            New content has landed in the `${{ matrix.from_branch }}` branch, so let's merge the changes into `${{ matrix.to_branch }}`.