ci.yml

# Gradient-Free-Optimizers CI Pipeline
#
# Pipeline Structure:
# 1. Code Quality (gate) - Must pass before anything else runs
# 2. API Smoke Tests (gate) - Fast API freeze tests, must pass before main tests
# 3. Main Tests (parallel):
#    - OS Matrix Tests (Ubuntu, macOS, Windows × Python versions)
#    - Dependency Isolation Tests (no-sklearn, no-scipy)
# 4. Coverage - Runs after all tests pass

name: CI

on:
  push:
    branches:
      - main
      - dev
  pull_request:
    branches:
      - main
      - dev

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

jobs:
  # ===========================================================================
  # STAGE 1: Code Quality (gate)
  # ===========================================================================
  code-quality:
    name: Code Quality
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install pre-commit
        run: python -m pip install --no-cache-dir pre-commit

      - name: Get changed files
        id: changed-files
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            CHANGED_FILES=$(git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.sha }} | tr '\n' ' ')
          else
            CHANGED_FILES=$(git diff --name-only HEAD~1 HEAD | tr '\n' ' ')
          fi
          echo "CHANGED_FILES=${CHANGED_FILES}" >> $GITHUB_ENV

      - name: Print changed files
        run: |
          echo "Changed files:" && echo "$CHANGED_FILES" | tr ' ' '\n'

      - name: Run pre-commit on changed files
        run: |
          if [ -n "$CHANGED_FILES" ]; then
            pre-commit run --color always --files $CHANGED_FILES --show-diff-on-failure
          else
            echo "No changed files to check."
          fi

  # ===========================================================================
  # STAGE 2: API Smoke Tests (gate)
  # ===========================================================================
  api-smoke-tests:
    name: API Smoke Tests
    runs-on: ubuntu-latest
    needs: code-quality
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          python -m pip install build
          make install
          make install-test-requirements

      - name: Run API smoke tests
        run: |
          python -m pytest tests/test_api/ -v --tb=short -p no:warnings

  # ===========================================================================
  # STAGE 3a: Main Tests - OS Matrix
  # ===========================================================================
  test-matrix:
    name: Tests (${{ matrix.os }}, py${{ matrix.python-version }}, np${{ matrix.numpy-version }})
    runs-on: ${{ matrix.os }}
    needs: api-smoke-tests
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest]
        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
        numpy-version: ["1", "2"]
        exclude:
          # numpy 1.x not compatible with Python 3.13+
          - python-version: "3.13"
            numpy-version: "1"
          - python-version: "3.14"
            numpy-version: "1"
          # pandas 1.x has no pre-built wheel for Python 3.12, source build
          # broken since setuptools 81 removed pkg_resources (Feb 2026)
          - python-version: "3.12"
            numpy-version: "1"
          # Reduce macOS/Windows matrix to save CI minutes
          - os: macos-latest
            numpy-version: "1"
          - os: windows-latest
            numpy-version: "1"
      fail-fast: false

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}

      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          python -m pip install build
          make install
          make install-test-requirements

      - name: Install specific numpy/pandas versions
        shell: bash
        run: |
          if [ "${{ matrix.numpy-version }}" = "1" ]; then
            python -m pip install "numpy>=1.18.1,<2.0.0" "pandas>=1.0,<2.0"
          else
            python -m pip install "numpy>=2.0,<3.0" "pandas>=2.0,<3.0"
          fi

      - name: Run main tests
        run: |
          python -m pytest tests/test_main/ -v --tb=short -p no:warnings

  # ===========================================================================
  # STAGE 3b: Dependency Isolation Tests - No sklearn
  # ===========================================================================
  # TEMPORARILY DISABLED - Re-enable when dependency isolation testing is needed
  # test-no-sklearn:
  #   name: Tests (no sklearn)
  #   runs-on: ubuntu-latest
  #   needs: api-smoke-tests
  #   steps:
  #     - name: Checkout code
  #       uses: actions/checkout@v4

  #     - name: Set up Python 3.11
  #       uses: actions/setup-python@v5
  #       with:
  #         python-version: "3.11"

  #     - name: Install minimal dependencies (no sklearn)
  #       run: |
  #         python -m pip install --upgrade pip
  #         python -m pip install build numpy pandas pytest
  #         python -m pip install scipy

  #     - name: Build and install package
  #       run: |
  #         python -m pip install build
  #         python -m build
  #         pip install dist/*.whl

  #     - name: Verify sklearn is NOT installed
  #       run: |
  #         python -c "
  #         import sys
  #         try:
  #             import sklearn
  #             print('ERROR: sklearn is installed but should not be!')
  #             sys.exit(1)
  #         except ImportError:
  #             print('OK: sklearn is not installed')
  #         "

  #     - name: Run dependency isolation tests
  #       run: |
  #         python -m pytest tests/test_dependencies/test_no_sklearn.py -v --tb=short -p no:warnings

  # ===========================================================================
  # STAGE 3b: Dependency Isolation Tests - No scipy
  # ===========================================================================
  test-no-scipy:
    name: Tests (no scipy)
    runs-on: ubuntu-latest
    needs: api-smoke-tests
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install minimal dependencies (no scipy)
        run: |
          python -m pip install --upgrade pip
          python -m pip install build numpy pandas pytest tqdm

      - name: Build and install package
        run: |
          python -m pip install build
          python -m build
          pip install dist/*.whl

      - name: Verify scipy is NOT installed
        run: |
          python -c "
          import sys
          try:
              import scipy
              print('ERROR: scipy is installed but should not be!')
              sys.exit(1)
          except ImportError:
              print('OK: scipy is not installed')
          "

      - name: Run dependency isolation tests
        run: |
          python -m pytest tests/test_dependencies/test_no_scipy.py -v --tb=short -p no:warnings

  # ===========================================================================
  # STAGE 3c: Dependency Isolation Tests - No numpy (pure Python)
  # ===========================================================================
  test-no-numpy:
    name: Tests (no numpy, pure Python)
    runs-on: ubuntu-latest
    needs: api-smoke-tests
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install minimal dependencies (no numpy, no scipy)
        run: |
          python -m pip install --upgrade pip
          python -m pip install build pytest tqdm

      - name: Build and install package
        run: |
          python -m pip install build
          python -m build
          pip install dist/*.whl

      - name: Uninstall numpy and pandas (test pure Python mode)
        run: |
          pip uninstall numpy pandas -y

      - name: Verify numpy and pandas are NOT installed
        run: |
          python -c "
          import sys
          errors = []
          for mod in ('numpy', 'pandas'):
              try:
                  __import__(mod)
                  errors.append(f'{mod} is installed but should not be')
              except ImportError:
                  print(f'OK: {mod} is not installed')
          if errors:
              for e in errors:
                  print(f'ERROR: {e}')
              sys.exit(1)
          "

      - name: Verify array backend uses pure Python
        run: |
          python -c "
          from gradient_free_optimizers._array_backend import _backend_name, HAS_NUMPY
          assert not HAS_NUMPY, 'HAS_NUMPY should be False'
          assert _backend_name == 'pure', f'Expected pure backend, got {_backend_name}'
          print('OK: using pure Python array backend')
          "

      - name: Run dependency isolation tests
        run: |
          python -m pytest tests/test_dependencies/test_no_numpy.py -v --tb=short -p no:warnings

  # ===========================================================================
  # STAGE 3d: C Extension Tests (no numpy, with compiled C backend)
  # ===========================================================================
  test-c-extension:
    name: Tests (C extension, no numpy)
    runs-on: ubuntu-latest
    needs: api-smoke-tests
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install build dependencies
        run: |
          python -m pip install --upgrade pip
          python -m pip install build pandas pytest tqdm setuptools

      - name: Build and install package (with C extension)
        run: |
          python -m pip install build
          python -m build
          pip install dist/*.whl

      - name: Uninstall numpy (keep C extension)
        run: |
          pip uninstall numpy -y || true

      - name: Verify C extension is active
        run: |
          python -c "
          from gradient_free_optimizers._array_backend import _backend_name, HAS_NUMPY, HAS_C_EXTENSION
          assert not HAS_NUMPY, 'numpy should not be installed'
          assert HAS_C_EXTENSION, 'C extension should be available'
          assert _backend_name == 'c_extension', f'Expected c_extension backend, got {_backend_name}'
          print('OK: using C extension array backend')
          "

      - name: Run C extension unit tests
        run: |
          python -m pytest tests/test_internal/test_array_backend/test_c_extension.py -v --tb=short -p no:warnings

      - name: Run dependency isolation tests
        run: |
          python -m pytest tests/test_dependencies/test_no_numpy.py -v --tb=short -p no:warnings

  # ===========================================================================
  # STAGE 4: Coverage Report (only on Ubuntu with full dependencies)
  # ===========================================================================
  coverage:
    name: Coverage Report
    runs-on: ubuntu-latest
    needs: [test-matrix, test-no-scipy, test-no-numpy, test-c-extension]
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          python -m pip install build
          make install
          make install-test-requirements

      - name: Run tests with coverage
        run: |
          python -m pytest tests/test_main/ tests/test_api/ \
            --cov=gradient_free_optimizers \
            --cov-report=term-missing \
            --cov-report=xml \
            -p no:warnings

      - name: Upload coverage to Codecov
        uses: codecov/codecov-action@v5
        with:
          token: ${{ secrets.CODECOV_TOKEN }}
          files: ./coverage.xml
          fail_ci_if_error: false
          verbose: true