coverage.yml

name: coverage

on:
  pull_request:
    branches: [master, main]
  push:
    branches: [master, main]

permissions:
  contents: read

jobs:
  coverage:
    runs-on: ubuntu-latest
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
        with:
          # Full history so diff-cover can resolve origin/<base_ref>.
          fetch-depth: 0
      - uses: actions/setup-node@v4
        with:
          node-version: 20
          cache: npm
      - run: npm ci
      - run: npm test -- --coverage
      - uses: codecov/codecov-action@v4
        if: always()
        with:
          fail_ci_if_error: false

      # ------------------------------------------------------------------
      # Org patch-coverage mandate: every changed line in a PR diff must be
      # covered by a test (100%). Tool: diff-cover
      # (https://github.com/Bachmann1234/diff-cover). vitest's v8 provider
      # emits lcov with src/*.ts(x) paths + source-mapped line numbers, so it
      # lines up directly with the PR diff. `npm run gate` is untouched.
      # ------------------------------------------------------------------
      - name: Generate lcov coverage
        if: github.event_name == 'pull_request'
        run: npx vitest run --coverage --coverage.provider=v8 --coverage.reporter=lcov --coverage.reportsDirectory=coverage
      - uses: actions/setup-python@v5
        if: github.event_name == 'pull_request'
        with:
          python-version: '3.12'
      - name: Install diff-cover
        if: github.event_name == 'pull_request'
        run: pip install diff-cover
      - name: Patch coverage gate (100% of changed lines)
        if: github.event_name == 'pull_request'
        run: |
          git fetch origin "${{ github.base_ref }}" --depth=1 || true
          diff-cover coverage/lcov.info \
            --compare-branch="origin/${{ github.base_ref }}" \
            --fail-under=100