create-hotfix-pr.yml

name: Create Hotfix PR

on:
  pull_request:
    types:
      - closed # Trigger when a PR is closed
    branches:
      - 'release-candidate/*' # Trigger for any branch starting with 'release-candidate/'

jobs:
  create_hotfix_pr:
    # Only run this job if the PR was actually merged
    if: github.event.pull_request.merged == true
    runs-on: ubuntu-latest
    permissions:
      contents: write       # To push branches and commit changes
      pull-requests: write # To create the pull request

    env:
      BOT_NAME: "flow360-auto-hotfix-bot" # Name for the git committer
      BOT_EMAIL: "flow360-auto-hotfix-bot@users.noreply.github.com" # Email for the git committer

    steps:

      - name: Checkout Code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Configure Git
        run: |
          git config user.name "${{ env.BOT_NAME }}"
          git config user.email "${{ env.BOT_EMAIL }}"

      - name: Get Merged Commit SHA (Assuming Squash Merge)
        id: get_commit
        # This SHA reliably points to the single commit if squash-and-merge was used.
        # If using merge commits, this SHA points to the merge commit itself,
        # which might be harder to cherry-pick cleanly.
        run: |
          echo "sha=${{ github.event.pull_request.merge_commit_sha }}" >> $GITHUB_OUTPUT
          echo "branch_name=${{ github.event.pull_request.head.ref }}" >> $GITHUB_OUTPUT
          echo "base_branch=${{ github.event.pull_request.base.ref }}" >> $GITHUB_OUTPUT

      - name: Get Hotfix Target Branches
        id: get_target_branches
        run: |
          PR_BASE_BRANCH="${{ steps.get_commit.outputs.base_branch }}"
          echo "PR was merged into: $PR_BASE_BRANCH"

          TARGET_BRANCHES=("main") # Always target main for hotfix

          # Get all remote 'release-candidate' branches with version pattern as YY.I or YY.II
          ALL_RELEASE_CANDIDATE_BRANCHES=$(git branch -r | grep 'origin/release-candidate/' | sed 's/.*origin\///' | grep -E '^release-candidate/[0-9]{2}\.[0-9]{1,2}$' | sort -V)
          echo "Found release-candidate branches: $ALL_RELEASE_CANDIDATE_BRANCHES"

          # Determine the version of the current PR's base branch
          # Example: release-candidate/25.5 -> 25.05 (for proper numerical comparison)
          PR_BASE_VERSION=$(echo "$PR_BASE_BRANCH" | sed -n 's/release-candidate\/\([0-9]\{2\}\)\.\([0-9]\{1,2\}\)/\1.\2/p')
          
          # Handle cases like 25.5 vs 25.05 for comparison
          if [[ "$PR_BASE_VERSION" =~ ^[0-9]{2}\.[0-9]$ ]]; then
            PR_BASE_VERSION=$(echo "$PR_BASE_VERSION" | awk '{printf "%s%02d", substr($1,1,3), substr($1,4)}')
          fi

          if [[ -n "$PR_BASE_VERSION" ]]; then
            echo "Base branch version: $PR_BASE_VERSION"
            for branch in $ALL_RELEASE_CANDIDATE_BRANCHES; do
              # Extract version for comparison
              BRANCH_VERSION=$(echo "$branch" | sed -n 's/release-candidate\/\([0-9]\{2\}\)\.\([0-9]\{1,2\}\)/\1.\2/p')
              
              if [[ -n "$BRANCH_VERSION" ]]; then
                if [[ "$BRANCH_VERSION" =~ ^[0-9]{2}\.[0-9]$ ]]; then
                  BRANCH_VERSION=$(echo "$BRANCH_VERSION" | awk '{printf "%s%02d", substr($1,1,3), substr($1,4)}')
                fi

                # Compare versions
                if (( $(echo "$BRANCH_VERSION > $PR_BASE_VERSION" | bc -l) )); then
                  TARGET_BRANCHES+=("$branch")
                  echo "Adding $branch (version $BRANCH_VERSION) as it's higher than $PR_BASE_BRANCH (version $PR_BASE_VERSION)"
                fi
              fi
            done
          fi

          # Prepare output for next step
          HOTFIX_BRANCHES_JSON=$(printf '%s\n' "${TARGET_BRANCHES[@]}" | jq -R . | jq -s .)
          DELIMITER=$(uuidgen) # Generate a unique delimiter
          echo "HOTFIX_BRANCHES<<$DELIMITER" >> $GITHUB_OUTPUT
          echo "$HOTFIX_BRANCHES_JSON" >> $GITHUB_OUTPUT
          echo "$DELIMITER" >> $GITHUB_OUTPUT
          echo "Calculated hotfix target branches: ${TARGET_BRANCHES[@]}"


      - name: Define Branch Names
        id: define_branches
        run: |
          ORIGINAL_PR_NUMBER=${{ github.event.pull_request.number }}
          # Convert JSON array to space-separated list
          BRANCHES=$(echo '${{ steps.get_target_branches.outputs.HOTFIX_BRANCHES }}' | jq -r '.[]')
          
          # Create outputs for all branches
          branch_list=""
          for branch in $BRANCHES; do
            new_branch="hotfix-${branch//\//-}-pr${ORIGINAL_PR_NUMBER}" # Replace '/' with '-' for new branch name
            branch_list+="${branch}:${new_branch} "
          done
          
          # Remove trailing space and store the list
          branch_list="${branch_list% }"
          echo "branch_pairs=${branch_list}" >> $GITHUB_OUTPUT

      - name: Create and Process Hotfix Branches
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_TITLE: ${{ github.event.pull_request.title }}
        run: |
          # Read branch pairs and process each one
          IFS=' ' read -r -a PAIRS <<< "${{ steps.define_branches.outputs.branch_pairs }}"

          for pair in "${PAIRS[@]}"; do
            IFS=':' read -r base_branch new_branch <<< "$pair"

            echo "Processing hotfix for branch: $base_branch"

            # Create and switch to new branch
            git checkout "$base_branch"
            git pull origin "$base_branch"
            git checkout -b "$new_branch"

            # Attempt cherry-pick
            if ! git cherry-pick ${{ steps.get_commit.outputs.sha }} --empty=keep; then
              echo "Cherry-pick encountered conflicts for $base_branch, attempting to resolve..."
              git add -A
              # Check if there are actual changes staged after conflict resolution attempt
              if git diff --cached --quiet; then
                  echo "Conflict resolution resulted in no changes. Aborting cherry-pick."
                  git cherry-pick --abort
                  continue # Skip PR creation if no changes after resolution
              fi
              git cherry-pick --continue

              if [ $? -eq 0 ]; then
                echo "Successfully resolved conflicts for $base_branch"
                had_conflicts="true"
              else
                echo "Failed to resolve conflicts for $base_branch"
                git cherry-pick --abort
                continue
              fi
            else
              echo "Cherry-pick successful for $base_branch"
              had_conflicts="false"
            fi

            CHANGED_FILES=$(git diff-tree --no-commit-id --name-only -r HEAD)
            if [ -z "$CHANGED_FILES" ]; then
                echo "Cherry-pick resulted in no changes, skipping PR creation for $base_branch"
                git reset --hard HEAD^ # Discard the empty commit if one was created by cherry-pick
                continue
            fi

            echo "Changed files:"
            echo "$CHANGED_FILES"

            # Push branch
            if git push origin "$new_branch"; then
              echo "Successfully pushed branch $new_branch"

              # Create PR
              PR_NUMBER="${{ github.event.pull_request.number }}"
              PR_URL="${{ github.event.pull_request.html_url }}"
              PR_AUTHOR="${{ github.event.pull_request.user.login }}"

              # Adjust PR title based on the target branch
              if [[ "$base_branch" == "main" ]]; then
                HOTFIX_PR_TITLE="[Hotfix Main]: $PR_TITLE"
              else
                base_branch_name=${base_branch#"release-candidate/"}
                HOTFIX_PR_TITLE="[Hotfix $base_branch_name]: $PR_TITLE"
              fi

              PR_BODY="Hotfix of PR #${PR_NUMBER} (${PR_URL}) to the \`${base_branch}\` branch.
              Hey @${PR_AUTHOR}, please review this hotfix PR created from your original PR."

              # Add conflict warning if needed
              if [[ "$had_conflicts" == "true" ]]; then
                PR_BODY="${PR_BODY}

          ### ⚠️ **Note:** This PR had conflicts with the base branch and was resolved automatically. Please review the changes carefully."
              fi

              # Create PR using gh cli
              gh pr create \
                --title "$HOTFIX_PR_TITLE" \
                --body "$PR_BODY" \
                --head "$new_branch" \
                --base "$base_branch" \
                --label "auto-hotfix" \
                --assignee "$PR_AUTHOR" \
                --draft
            else
              echo "Failed to push branch $new_branch"
            fi
          done