python_release_prep.yaml

name: Python Release Prep

# Sets the next version in python/pyproject.toml, renders the changelog fragments in
# python/changelog.d into python/CHANGELOG.md and opens a pull request. Merging that pull request
# starts the Python Release Tag workflow.

on:
  workflow_dispatch:
    inputs:
      version:
        description: Optional explicit X.Y.Z. Skips the automatic bump from the fragment types.
        type: string
        required: false

permissions:
  contents: write
  pull-requests: write

jobs:
  prep:
    name: Open release prep PR
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          ref: ${{ github.event.repository.default_branch }}

      - name: Set up uv
        uses: astral-sh/setup-uv@v6

      - name: Compute next version
        id: version
        env:
          VERSION_OVERRIDE: ${{ inputs.version }}
        run: |
          version=$(python3 python/scripts/release_version.py --version "$VERSION_OVERRIDE")
          echo "version=$version" >> "$GITHUB_OUTPUT"
          echo "Next version: $version"

      - name: Set version and render changelog
        env:
          VERSION: ${{ steps.version.outputs.version }}
        run: |
          cd python
          uv version --no-sync "$VERSION"
          uvx towncrier@26.9.0 build --yes --version "$VERSION" --date "$(date '+%B %-d, %Y')"

      - name: Open pull request
        env:
          GH_TOKEN: ${{ github.token }}
          VERSION: ${{ steps.version.outputs.version }}
          BASE_BRANCH: ${{ github.event.repository.default_branch }}
        run: |
          branch="release/python-v${VERSION}"
          title="Python(chore): v${VERSION} release prep"
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git checkout -b "$branch"
          git add -A python/pyproject.toml python/uv.lock python/CHANGELOG.md python/changelog.d
          git commit -m "$title"
          # A rerun for the same version replaces the branch and updates its open pull request.
          git push --force origin "$branch"
          if [[ "$(gh pr view "$branch" --json state -q .state 2>/dev/null)" == "OPEN" ]]; then
            echo "Updated the open pull request for ${branch}."
            exit 0
          fi
          gh pr create \
            --base "$BASE_BRANCH" \
            --head "$branch" \
            --title "$title" \
            --body "Sets the version to ${VERSION} and renders its changelog fragments. Review the version and entries before merging. Merging this pull request tags \`python/v${VERSION}\` and publishes it. See \`python/changelog.d/README.md\`."