phonopy test with PHONOPY_NO_C_EXT (Rust-only backend) workflow (phonopy/phonopy)

name: phonopy test with PHONOPY_NO_C_EXT (Rust-only backend)
 
# Run the test suite against a wheel built with PHONOPY_NO_C_EXT=1.  This
# verifies that lang="Rust" via the phonors crate covers every dispatch
# site that the C extension used to.  Anything that fails here is a
# missing-Rust-port site (per phonopy_RUST_MIGRATION.md, Phase 6A).
 
on:
  pull_request:
    branches: [main]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build-linux-no-c:
    timeout-minutes: 30
    runs-on: latchkey-small
    defaults:
      run:
        shell: bash -l {0}
    strategy:
      matrix:
        python-version: ["3.13"]
 
    steps:
      - uses: actions/checkout@v6
        with:
          # setuptools_scm needs tags to compute the phonopy version;
          # actions/checkout's default shallow clone hides them.
          fetch-depth: 0
      - uses: conda-incubator/setup-miniconda@v3
        with:
          miniforge-version: latest
      - name: Install dependencies
        run: |
          conda activate test
          conda install --yes -c conda-forge python=${{ matrix.python-version }}
          conda install --yes -c conda-forge matplotlib-base pyyaml scipy numpy spglib h5py pip pytest pypolymlp ase rust maturin
      - name: Setup symfc
        run: |
          conda activate test
          git clone https://github.com/symfc/symfc.git
          cd symfc
          pip install -e . -vvv
      - name: Setup phonors
        run: |
          conda activate test
          git clone https://github.com/phonopy/phonors.git
          cd phonors
          maturin develop --release
      - name: Setup phonopy without C extension
        env:
          PHONOPY_NO_C_EXT: "1"
          # Force the Make generator so scikit-build-core does not look
          # for Ninja.  CMakeLists.txt early-returns under
          # PHONOPY_NO_C_EXT=1, so no actual compilation happens.
          CMAKE_GENERATOR: "Unix Makefiles"
        run: |
          conda activate test
          pip install -e . -vvv
      - name: Verify _phonopy is absent
        run: |
          conda activate test
          python -c "
          try:
              import phonopy._phonopy
          except ImportError:
              print('OK: phonopy._phonopy is absent.')
          else:
              raise SystemExit('phonopy._phonopy was unexpectedly built.')
          "
      - name: Test with pytest (Rust backend)
        run: |
          conda activate test
          pytest test