Code_Coverage.yml

# ─────────────────────────────────────────────────────────────────────────────
# CXXGraph – Code Coverage
#
# Generates an LCOV / gcovr HTML report and uploads to Codecov.
# Runs on: Ubuntu 24.04 + GCC 14 (latest stable toolchain with best gcov support)
#
# Two modes:
#   • push   → upload to Codecov (requires CODECOV_TOKEN secret)
#   • PR     → generate report & attach as artifact (no token needed)
# ─────────────────────────────────────────────────────────────────────────────
name: Code Coverage

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

permissions:
  contents: read

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

env:
  CPM_SOURCE_CACHE: ~/.cache/cpm

jobs:
  coverage:
    name: "Coverage · GCC 14 · C++17"
    runs-on: ubuntu-24.04
    timeout-minutes: 30

    steps:

      - name: Checkout
        uses: actions/checkout@v6
        with:
          fetch-depth: 1

      # ── Toolchain ─────────────────────────────────────────────────────
      - name: Install dependencies
        run: |
          sudo apt-get update -q
          sudo apt-get install -y --no-install-recommends \
            gcc-14 g++-14 lcov gcovr ninja-build

      - name: Install Ninja
        uses: seanmiddleditch/gha-setup-ninja@v6

      # ── CPM cache ─────────────────────────────────────────────────────
      - name: Cache CPM packages
        uses: actions/cache@v5
        with:
          path: ~/.cache/cpm
          key: cpm-ubuntu-coverage-${{ hashFiles('**/CMakeLists.txt') }}
          restore-keys: cpm-ubuntu-coverage-

      # ── Configure ─────────────────────────────────────────────────────
      - name: Configure CMake
        env:
          CC:  gcc-14
          CXX: g++-14
        run: |
          cmake -B build \
            -G Ninja \
            -DCMAKE_BUILD_TYPE=Debug \
            -DCMAKE_CXX_STANDARD=17 \
            -DCMAKE_CXX_STANDARD_REQUIRED=ON \
            -DCMAKE_CXX_EXTENSIONS=OFF \
            -DTEST=ON \
            -DCODE_COVERAGE=ON

      # ── Build & run tests ─────────────────────────────────────────────
      - name: Build
        run: cmake --build build --parallel

      - name: Run tests
        working-directory: build/test
        run: ./test_exe

      # ── Generate LCOV report ──────────────────────────────────────────
      - name: Capture coverage data
        working-directory: build
        run: |
          lcov \
            --capture \
            --directory . \
            --output-file coverage_raw.info \
            --ignore-errors mismatch \
            --gcov-tool gcov-14

      - name: Remove noise (system / third-party headers)
        working-directory: build
        run: |
          lcov \
            --remove coverage_raw.info \
              '/usr/*' \
              '*/googletest/*' \
              '*/googlemock/*' \
              '*/zlib/*' \
              '*/test/*' \
              '*/benchmark/*' \
              '*/CPM_packages/*' \
            --output-file coverage.info \
            --ignore-errors unused

      - name: Show coverage summary
        working-directory: build
        run: lcov --summary coverage.info

      # ── Generate browsable HTML report ────────────────────────────────
      - name: Generate HTML report
        working-directory: build
        run: |
          genhtml coverage.info \
            --output-directory coverage_html \
            --title "CXXGraph Coverage" \
            --legend \
            --show-details \
            --highlight

      # ── Also generate gcovr XML (for tooling / IDE integrations) ──────
      - name: Generate gcovr XML
        working-directory: build
        run: |
          gcovr \
            --root .. \
            --exclude '.*googletest.*' \
            --exclude '.*googlemock.*' \
            --exclude '.*zlib.*' \
            --exclude '.*test.*' \
            --exclude '.*CPM_packages.*' \
            --xml coverage.xml \
            --xml-pretty

      # ── Upload to Codecov ─────────────────────────────────────────────
      - name: Upload to Codecov
        uses: codecov/codecov-action@v6
        with:
          token:            ${{ secrets.CODECOV_TOKEN }}
          files:            build/coverage.info
          flags:            unittests
          name:             codecov-umbrella
          fail_ci_if_error: true

      # ── Attach HTML report as artifact (always, useful on PRs) ────────
      - name: Upload HTML coverage report
        if: always()
        uses: actions/upload-artifact@v7
        with:
          name: coverage-report-html
          path: build/coverage_html/
          retention-days: 14

      - name: Upload LCOV file
        if: always()
        uses: actions/upload-artifact@v7
        with:
          name: coverage-lcov
          path: build/coverage.info
          retention-days: 14