name: Ensure Version Consistency on PR to Release

on:
  pull_request:
    branches:
      - release

jobs:
  check_version_and_tag:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: true  # Terminate the job immediately if any step fails
    steps:
      - name: Check out code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0 # Necessary to fetch all tags for comparison

      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: '3.x'

      - name: Install dependencies
        run: |
          python -m pip install toml

      - name: Extract version from pyproject.toml
        run: |
          echo "Extracting version from pyproject.toml"
          VERSION=$(python -c 'import toml; print(toml.load("pyproject.toml")["project"]["version"])')
          echo "Version in pyproject.toml is $VERSION"
          echo "VERSION=$VERSION" >> $GITHUB_ENV

      - name: Get tag for the PR's head commit
        run: |
          PR_HEAD_SHA=$(jq -r .pull_request.head.sha < "$GITHUB_EVENT_PATH")
          TAG=$(git tag --contains $PR_HEAD_SHA)
          echo "Tag on PR's head commit is $TAG"
          echo "TAG=$TAG" >> $GITHUB_ENV

      - name: Compare version and tag
        run: |
          if [ -z "$TAG" ]; then
            echo "Head commit of PR is not tagged. Ensure the head commit of PRs onto release is tagged with the version number."
            exit 1
          elif [ "$VERSION" != "$TAG" ]; then
            echo "Version in pyproject.toml ($VERSION) does not match the git tag ($TAG)."
            exit 1
          else
            echo "Version and git tag match. Check passed."