build.yml

on:
  # Run the workflow when new tags are created.
  push:
    tags:
      - v*
  # Allow the workflow to be triggered manually.
  workflow_dispatch:

name: Build

permissions:
  contents: write
  pull-requests: write

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      PUBLISH_BRANCH: publish
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install uv
        uses: astral-sh/setup-uv@v5

      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: 3.12

      - name: Create a name for the build branch
        run: |
          git checkout main
          echo "BUILD_BRANCH=build-$(git rev-parse --short HEAD)" >> $GITHUB_ENV

      # Reset the `publish` branch to point to `main`, because we use the `publish` branch
      # only to store the build artifacts, not for version control.
      - name: Reset the publish branch
        run: |
          git checkout -b $PUBLISH_BRANCH || true
          git checkout $PUBLISH_BRANCH
          git reset --hard origin/main
          git push --force origin $PUBLISH_BRANCH
          git checkout main

      # Delete the build branch if it already exists,
      # as the `peter-evans/create-pull-request` action used below will update the branch
      # if it exists, which we don't want.
      # Note: deleting the build branch will also close the corresponding PR, if it exists.
      - name: Delete the build branch
        run: |
          git branch -D $BUILD_BRANCH || true
          git push --force --delete origin $BUILD_BRANCH || true

      - name: Build the publication
        run: |
          git checkout main
          uv run --no-project _build.py

      # Open a PR to merge the build artifacts into the `publish` branch.
      # Note: this action automatically creates the build branch and commits all unstaged changes to it.
      - name: Open PR
        uses: peter-evans/create-pull-request@v7
        env:
          PR_BODY: |
            This PR creates a new version of the public Quarto publication. It was automatically created by the `build.yml` workflow.

            To preview this version of the publication, check out this PR branch locally and run `quarto preview`.

            To publish this version of the publication, merge this PR into the `publish` branch.
        with:
          # `base` is the target branch for the PR.
          base: ${{ env.PUBLISH_BRANCH }}
          # `branch` is the source branch for the PR.
          branch: ${{ env.BUILD_BRANCH }}
          commit-message: "Update the public Quarto publication"
          title: "[Publication] Update the public Quarto publication"
          body: ${{ env.PR_BODY }}