create-merge-from-previous-release-branch-pr.yml

name: create-merge-from-previous-release-branch
on:
  push:
    branches: ["release/*"]
  workflow_dispatch:

permissions: {}
jobs:
  setup:
    if: github.repository == 'opf/openproject'
    runs-on: ubuntu-latest
    outputs:
      previous_release_branch: ${{ steps.find_release_branches.outputs.previous_branch }}
      latest_release_branch: ${{ steps.find_release_branches.outputs.latest_branch }}
    steps:
      - id: find_release_branches
        env:
          GITHUB_TOKEN: ${{ secrets.OPENPROJECTCI_GH_CORE_PAT }}
          GITHUB_REPOSITORY: ${{ github.repository }}
        run: |
          LATEST_BRANCHES=$(gh api --paginate \
            "repos/$GITHUB_REPOSITORY/branches?protected=true&per_page=100" \
            --jq '.[].name' | grep '^release/' | sort --version-sort | tail -2
          )
          LATEST_BRANCH=$(echo "$LATEST_BRANCHES" | tail -1)
          PREVIOUS_BRANCH=$(echo "$LATEST_BRANCHES" | head -1)
          if [ -z "$LATEST_BRANCH" ] || [ -z "$PREVIOUS_BRANCH" ]; then
            echo "Invalid release branches found: latest=$LATEST_BRANCH, previous=$PREVIOUS_BRANCH"
            exit 1
          fi
          echo "Found previous release branch: $PREVIOUS_BRANCH"
          echo "previous_branch=${PREVIOUS_BRANCH}" >> $GITHUB_OUTPUT
          echo "Found latest release branch: $LATEST_BRANCH"
          echo "latest_branch=${LATEST_BRANCH}" >> $GITHUB_OUTPUT
  merge-or-create-pr:
    if: github.event_name == 'workflow_dispatch' || (github.event_name == 'push' && github.ref_name == needs.setup.outputs.previous_release_branch)
    env:
      RELEASE_BRANCH: ${{ needs.setup.outputs.latest_release_branch }}
      PREVIOUS_RELEASE_BRANCH: ${{ needs.setup.outputs.previous_release_branch }}

    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@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
        with:
          ref: ${{ env.RELEASE_BRANCH }}

      - name: Fetch both release branches with sufficient history
        run: |
          # Calculate a reasonable date to fetch from (e.g., 6 months ago)
          SINCE_DATE=$(date -d '3 months ago' '+%Y-%m-%d')
          echo "Fetching commits since: $SINCE_DATE"

          # Fetch both branches with commits since the calculated date
          git fetch --shallow-since="$SINCE_DATE" origin "$RELEASE_BRANCH" "$PREVIOUS_RELEASE_BRANCH" || {
            echo "Shallow-since fetch failed, trying with depth strategy..."

            # Fallback: Use progressive deepening
            git fetch --depth=50 origin "$RELEASE_BRANCH" "$PREVIOUS_RELEASE_BRANCH"
            for depth in 100 200 500 1000; do
              if git merge-base --is-ancestor "origin/$PREVIOUS_RELEASE_BRANCH" "origin/$RELEASE_BRANCH" 2>/dev/null || \
                 git merge-base --is-ancestor "origin/$RELEASE_BRANCH" "origin/$PREVIOUS_RELEASE_BRANCH" 2>/dev/null || \
                 git merge-base "origin/$RELEASE_BRANCH" "origin/$PREVIOUS_RELEASE_BRANCH" >/dev/null 2>&1; then
                echo "Found sufficient history at depth $depth"
                break
              fi
              echo "Deepening to $depth commits..."
              git fetch --deepen=$((depth-50)) origin "$RELEASE_BRANCH" "$PREVIOUS_RELEASE_BRANCH" || true
            done
          }

      - name: Resolve bug in git https://stackoverflow.com/a/63879454/96823
        run: git repack -d

      - name: Verify we have sufficient history
        run: |
          echo "Checking if we can find merge-base between branches..."
          if git merge-base "origin/$RELEASE_BRANCH" "origin/$PREVIOUS_RELEASE_BRANCH" >/dev/null 2>&1; then
            MERGE_BASE=$(git merge-base "origin/$RELEASE_BRANCH" "origin/$PREVIOUS_RELEASE_BRANCH")
            echo "✅ Found merge-base: $MERGE_BASE"
          else
            echo "⚠️ Could not find merge-base, operations may be limited"
          fi

          echo "Branch $RELEASE_BRANCH has $(git rev-list --count origin/$RELEASE_BRANCH) commits"
          echo "Branch $PREVIOUS_RELEASE_BRANCH has $(git rev-list --count origin/$PREVIOUS_RELEASE_BRANCH) commits"

      - name: Create local tracking branches
        run: |
          git branch "$PREVIOUS_RELEASE_BRANCH" "origin/$PREVIOUS_RELEASE_BRANCH" || true
          git branch "$RELEASE_BRANCH" "origin/$RELEASE_BRANCH" || true

      - name: Required git config
        run: |
          git config user.name "OpenProject Actions CI"
          git config user.email "operations+ci@openproject.com"

      - name: Show diff
        run: git diff ..."$PREVIOUS_RELEASE_BRANCH"

      - name: Try merging or create a PR
        run: |
          if git diff --exit-code --quiet ..."$PREVIOUS_RELEASE_BRANCH"; then
            echo "Nothing to merge from $PREVIOUS_RELEASE_BRANCH into $RELEASE_BRANCH"
          else
            if git merge --no-edit --no-ff "$PREVIOUS_RELEASE_BRANCH" && git push origin "$RELEASE_BRANCH"; then
              echo "Successfully merged $PREVIOUS_RELEASE_BRANCH into $RELEASE_BRANCH and pushed"
            else
              # Close all previous PRs with label
              pr_numbers=$(gh pr list --label merge-previous-release-branch --json number --jq='.[].number')
              for pr_number in $pr_numbers; do
                gh pr close "$pr_number" --delete-branch
              done

              pr_body=$(
                echo 'Created by GitHub action'
                for pr_number in $pr_numbers; do
                  echo "Replaces #$pr_number"
                done
              )

              TEMP_BRANCH="merge-$PREVIOUS_RELEASE_BRANCH-$(date "+%Y%m%d%H%M%S")"

              git branch "$TEMP_BRANCH" "$PREVIOUS_RELEASE_BRANCH"

              git push origin "$TEMP_BRANCH"

              gh pr create \
                --base "$RELEASE_BRANCH" \
                --head "$TEMP_BRANCH" \
                --title "Merge $PREVIOUS_RELEASE_BRANCH into $RELEASE_BRANCH" \
                --body "$pr_body" \
                --label merge-previous-release-branch
              echo "Created a PR to merge $PREVIOUS_RELEASE_BRANCH ($TEMP_BRANCH) into $RELEASE_BRANCH"
            fi
          fi
        env:
          GITHUB_TOKEN: ${{ secrets.OPENPROJECTCI_GH_CORE_PAT }}