create-merge-release-into-dev-pr.yml

name: create-merge-release-into-dev-pr
on:
  workflow_dispatch:

env:
  BASE_BRANCH: test-dev

permissions: {}
jobs:
  setup:
    runs-on: ubuntu-latest
    outputs:
      latest_release_branch: ${{ steps.find_latest_release.outputs.branch }}
    steps:
    - id: find_latest_release
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        GITHUB_REPOSITORY: ${{ github.repository }}
      run: |
        BRANCH=$(curl -H "Authorization: token $GITHUB_TOKEN" \
          https://api.github.com/repos/$GITHUB_REPOSITORY/branches?protected=true | \
          jq -r '.[].name' | grep '^release/' | sort --version-sort | tail -1
        )
        if [ "$BRANCH" = "" ]; then
          echo "Invalid release branch found: $BRANCH"
          exit 1
        fi

        echo "branch=${BRANCH}" >> $GITHUB_OUTPUT

  merge-or-create-pr:
    permissions:
      contents: write # for git push
      pull-requests: write # for creating pull request

    runs-on: ubuntu-latest
    needs: setup
    timeout-minutes: 5
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          ref: ${{ env.BASE_BRANCH }} # TODO: DELETE ME
      - name: Try merging
        run: |
          # Fetching the dev and release branches without fetching their complete history
          # First fetch branches themselves excluding commits reachable by the other branch
          git fetch --shallow-exclude "$BASE_BRANCH" origin "$RELEASE_BRANCH"
          git fetch --shallow-exclude "$RELEASE_BRANCH" origin "$BASE_BRANCH"
          # Resolve bug in git https://stackoverflow.com/a/63879454/96823
          git repack -d
          # Get one commit more to connect the history of dev and release branches
          git fetch --deepen 1 origin "$BASE_BRANCH" "$RELEASE_BRANCH"

          # Create branch without checkout just to have shorter automatic commit message
          git branch "$RELEASE_BRANCH" origin/"$RELEASE_BRANCH"

          # Required config
          git config user.name "OpenProject Actions CI"
          git config user.email "operations+ci@openproject.com"

          if git diff --exit-code --quiet ..."$RELEASE_BRANCH"; then
            echo "Nothing to merge"
          else
            if git merge --no-edit --no-ff "$RELEASE_BRANCH"; then
              git push "$BASE_BRANCH"
            else
              gh pr create \
                --base "$BASE_BRANCH" \
                --head "$RELEASE_BRANCH" \
                --title "Merge $RELEASE_BRANCH into $BASE_BRANCH" \
                --body 'Created by GitHub action'
            end
          end
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          RELEASE_BRANCH: ${{ needs.setup.outputs.latest_release_branch }}