coverage.yaml

name: coverage

on:
  # this allows for `contents: write` and `pull-requests: write` from forks
  pull_request_target:

# limit default permissions to just read-only checkouts
permissions:
  contents: read

jobs:
  coverage:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        branch: [pr, main]
    outputs:
      cov-pr: ${{ steps.coverage.outputs.cov-pr }}
      cov-main: ${{ steps.coverage.outputs.cov-main }}
    steps:
      - name: Checkout
        uses: actions/checkout@v3
        with:
          # for safety, `pull_request_target` changes the default checkout to be the target branch, so we have to request the merge (we're limited to `permissions: {contents: read}`, so this is ok)
          ref: ${{ matrix.branch == 'main' && 'main' || (github.event.pull_request && format('refs/pull/{0}/merge', github.event.pull_request.number)) || '' }}

      - name: Bazel cache
        id: bazel-cache
        uses: actions/cache@v3
        with:
          path: ~/.cache/bazel
          key: ${{ runner.os }}-3.10-bazel-cache-${{ hashFiles('**/BUILD', '.bazelrc', '.bazelversion', 'WORKSPACE') }}
          restore-keys: ${{ runner.os }}-3.10-bazel-cache-

      - name: Install poetry
        run: pipx install poetry

      - name: Setup Python
        uses: actions/setup-python@v4
        with:
          python-version: "3.10"
          cache: poetry

      - name: Install dependencies
        run: poetry install --no-interaction

      - name: Run coverage
        id: coverage
        run: |
          poetry run ./tools/coverage.sh
          poetry run coverage json
          content=$(cat ./coverage.json)
          echo "cov-${{ matrix.branch }}=$content" >> $GITHUB_OUTPUT

  comment:
    runs-on: ubuntu-latest
    needs: [coverage]
    permissions:
      # needed to add coverage comment to the pull request
      pull-requests: write

    steps:
      - uses: actions/github-script@v6
        with:
          script: |
            const pr = ${{fromJson(needs.coverage.outputs.cov-pr).totals.percent_covered}};
            const main = ${{fromJson(needs.coverage.outputs.cov-main).totals.percent_covered}};
            const diff = pr - main;
            const report = `### Coverage report
            **Main**: ${main.toFixed(2)}% | **PR**: ${pr.toFixed(2)}% | **Diff: ${diff.toFixed(2)} ${diff >= 0 ? '✅' : '⚠️'}**`;
            await core.summary.addRaw(report).write()
            try {
              github.rest.issues.createComment({
                issue_number: context.issue.number,
                owner: context.repo.owner,
                repo: context.repo.repo,
                body: report
              })
            } catch (e) {
              console.log("Could not post comment to pull request", e)
            }