release.yml

name: Handle release process

# This workflow automates the release process.
# Only safe to use if the following conditions are met:
# 1. `main` is protected and requires a PR to merge.
# 2. Only squash-merging is allowed.
# 3. PRs are required to be up-to-date with `main` before merging.
# 4. Everyone is forbidden from creating releases manually.

on:
  # Case 1: manual trigger -> initiate release process
  workflow_dispatch:

  # Case 2: release PR is being updated -> update changelog
  push:
    branches:
      - 'bot/release/*'

  # Case 3: release PR is merged -> create a new release
  pull_request:
    types:
      - closed
    branches:
      - main

env:
  GH_TOKEN: ${{ secrets.PL_PASTEURBOT_PAT_PUBLIC }}

jobs:
  trigger-pr:
    runs-on: ubuntu-latest
    if: github.event_name == 'workflow_dispatch'

    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          token: ${{ secrets.PL_PASTEURBOT_PAT_PUBLIC }}
          fetch-depth: 0
          fetch-tags: true

      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version-file: "pyproject.toml"

      - name: Install git-cliff
        run: |
          pip install git-cliff

      - name: Generate changelog
        id: generate_changelog
        run: |
          git-cliff --output CHANGELOG.md --bump
          new_version=$(git-cliff --bumped-version)
          echo "new_version=$new_version" >> $GITHUB_OUTPUT

      - name: Trigger release PR
        run: |
          git config --global user.name "PasteurBot"
          git config --global user.email "hello@simulation.science"

          git checkout -b "bot/release/${{ steps.generate_changelog.outputs.new_version }}"
          git add CHANGELOG.md
          git commit -m "chore: update changelog"
          git push origin "bot/release/${{ steps.generate_changelog.outputs.new_version }}"

          pr_body=$(cat <<EOF
          This PR contains the generated changelog for the release ${{ steps.generate_changelog.outputs.new_version }}.

          ⚠️ **Merging this PR will immediately trigger a new release**. ⚠️

          To specify additional release notes, please edit this comment after the following line.

          ---
          EOF
          )

          gh pr create \
            --title "chore: release ${{ steps.generate_changelog.outputs.new_version }}" \
            --body "$pr_body" \
            --head "bot/release/${{ steps.generate_changelog.outputs.new_version }}" \
            --base "main"

  update-pr:
    runs-on: ubuntu-latest
    if: github.event_name == 'push' && startsWith(github.ref, 'refs/heads/bot/release/')

    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          token: ${{ secrets.PL_PASTEURBOT_PAT_PUBLIC }}
          fetch-depth: 0
          fetch-tags: true

      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version-file: "pyproject.toml"

      - name: Install git-cliff
        run: |
          pip install git-cliff

      - name: Generate changelog
        id: generate_changelog
        run: |
          git-cliff --output CHANGELOG.md --bump
          new_version=$(git-cliff --bumped-version)
          echo "new_version=$new_version" >> $GITHUB_OUTPUT

      - name: Update PR with changelog
        run: |
          git config --global user.name "PasteurBot"
          git config --global user.email "hello@simulation.science"

          git add CHANGELOG.md

          if git diff --cached --quiet; then
            echo "No changes to commit"
          else
            git commit -m "chore: update changelog before release"
            git push origin HEAD:${{ github.ref }}
          fi

  release:
    runs-on: ubuntu-latest
    if: github.event_name == 'pull_request' && github.event.pull_request.merged == true && startsWith(github.event.pull_request.head.ref, 'bot/release/')

    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          token: ${{ secrets.PL_PASTEURBOT_PAT_PUBLIC }}
          ref: ${{ github.event.pull_request.merge_commit_sha }}
          fetch-depth: 0
          fetch-tags: true

      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version-file: "pyproject.toml"

      - name: Install git-cliff
        run: |
          pip install git-cliff

      - name: Get version numbers
        id: get_version
        run: |
          current_version=$(gh release view --json tagName --jq '.tagName' || echo "v0.0.0")
          echo "current_version=$current_version" >> $GITHUB_OUTPUT

          new_version=$(git-cliff --bumped-version)
          echo "new_version=$new_version" >> $GITHUB_OUTPUT

      - name: Assemble release notes
        id: release_notes
        env:
          PR_BODY: ${{ github.event.pull_request.body }}
        run: |
          changelog=$(git-cliff --unreleased --bump --latest --strip all)
          # Strip off first line (which is the version number)
          changelog=$(printf "%s" "$changelog" | sed '1d')

          # Get custom notes from the PR body
          custom_notes="$PR_BODY"
          # Fix line endings
          custom_notes=$(echo "$custom_notes" | tr -d '\r')
          # Keep only the part after the first '---' line
          custom_notes=$(echo "$custom_notes" | sed -n '/^---$/,$p' | sed '1d')
          # Strip leading / trailing whitespace
          custom_notes=$(echo "$custom_notes" | sed 's/^[ \t]*//;s/[ \t]*$//')

          # Create the release notes file
          touch /tmp/notes.md
          echo "# Release ${{ steps.get_version.outputs.new_version }}" > /tmp/notes.md
          if [[ -n "$custom_notes" ]]; then
            printf "%s\n\n" "$custom_notes" >> /tmp/notes.md
          fi
          printf "## What's Changed\n%s\n" "$changelog" >> /tmp/notes.md

          # Append link to full diff
          echo -e "\n**Full diff**: https://github.com/${{ github.repository_owner }}/${{ github.repository }}/compare/${{ steps.get_version.outputs.current_version }}...${{ steps.get_version.outputs.new_version }}" >> /tmp/notes.md

          echo "release_note_file=/tmp/notes.md" >> $GITHUB_OUTPUT

      - name: Create new release
        run: |
          gh release create "${{ steps.get_version.outputs.new_version }}" \
            --title "${{ steps.get_version.outputs.new_version }}" \
            --notes-file "${{ steps.release_notes.outputs.release_note_file }}" \
            --target ${{ github.event.pull_request.merge_commit_sha }} \
            --latest