_lint.yml

# Reusable: lint (clang-format + cargo clippy + cargo fmt)
name: Lint

on:
  workflow_call: {}

permissions:
  contents: read

jobs:
  lint:
    runs-on: ubuntu-24.04
    timeout-minutes: 15
    steps:
      - uses: actions/checkout@v7 # v4.2.2

      - name: Install system deps
        run: |
          sudo apt-get update
          sudo apt-get install -y cmake ninja-build
          # Install clang-format via pip — the PyPI wheel provides an
          # exact version match (21.1.8) with the local dev environment
          # (Homebrew llvm@21, which is what `which clang-format` resolves
          # to on PATH). Ubuntu 24.04's default clang-format (v18) and the
          # LLVM apt repo's clang-format-21 produce different formatting,
          # causing spurious CI failures.
          pip install clang-format==21.1.8
          clang-format --version

      - name: Setup Rust
        uses: dtolnay/rust-toolchain@1.95.0 # pinned to match local dev
        with:
          components: clippy, rustfmt

      - name: Cache Cargo registry
        uses: actions/cache@v6 # v4.2.3
        with:
          path: |
            ~/.cargo/registry
            ~/.cargo/git
          # Cargo.lock is committed — use it as the precise cache key
          key: lint-cargo-registry-${{ hashFiles('**/Cargo.lock', '**/Cargo.toml') }}
          restore-keys: lint-cargo-registry-

      - name: Lint Rust (clippy)
        run: cargo clippy --all-targets -- -D warnings

      - name: Check formatting (Rust)
        run: cargo fmt --check

      - name: Lint C++ (clang-format)
        run: |
          set -e
          FILES=$(find engine/src engine/include -name '*.cpp' -o -name '*.h' 2>/dev/null)
          if [ -n "$FILES" ]; then
            echo "$FILES" | xargs clang-format --dry-run --Werror
            echo "  ✓ clang-format passed"
          fi