Add Clang Tidy Check (#193)

- Add clang-tidy file and check
- Removed unnecessary inline specifiers for member functions in spatial_hash.hpp.
- Initialized member variables in spatial_hash.hpp to default values.
- Updated assertions to check for emptiness instead of size in various locations.
- Changed shared pointer parameters to use const references for efficiency.
- Simplified conditional checks and improved readability in multiple files.
- Replaced manual checks for negative values with std::max in collision_mesh.cpp.
- Enhanced clarity in comments and function signatures across several files.
- Updated distance type enums to use uint8_t for better memory efficiency.
- Improved consistency in function parameter naming and usage.
- Cleaned up unused parameters and improved function documentation.

Author: zfergus

.clang-tidy

@@ -0,0 +1,54 @@
+Checks: >
+  -*,
+
+  # Standard C++ Guidelines (Modernization, Idioms)
+  modernize-*,
+  performance-*,
+  readability-*,
+
+  # Bug Detection and Safety
+  bugprone-*,
+
+  # Specific high-value checks (even if not in a group above)
+  google-runtime-int,
+  cppcoreguidelines-pro-type-member-init,
+
+  # Exclusions/Suppressions (Checks often considered too aggressive or subjective)
+  -bugprone-throwing-static-initialization,
+  -cppcoreguidelines-owning-memory,
+  -modernize-use-trailing-return-type,
+  -readability-avoid-const-params-in-decls,
+  -readability-avoid-nested-conditional-operator,
+  -readability-container-contains,
+  -readability-else-after-return,
+  -readability-function-cognitive-complexity,
+  -readability-identifier-length,
+  -readability-implicit-bool-conversion,
+  -readability-isolate-declaration,
+  -readability-magic-numbers,
+  -readability-math-missing-parentheses,
+  -readability-redundant-access-specifiers
+
+WarningsAsErrors: '*'
+HeaderFilterRegex: '.*(ipc/).*'
+UseColor: true
+FormatStyle: file
+ExtraArgs:
+  - '-isysroot/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk'
+CheckOptions:
+  readability-identifier-naming.ClassCase: CamelCase
+  readability-identifier-naming.ConstantParameterCase: lower_case
+  readability-identifier-naming.ConstantParameterIgnoredRegexp: '^(_.*)$'
+  readability-identifier-naming.FunctionCase: lower_case
+  readability-identifier-naming.FunctionIgnoredRegexp: '^(AbslHashValue|.*[123][Ddf].*)$'
+  readability-identifier-naming.GlobalConstantCase: UPPER_CASE
+  readability-identifier-naming.MemberCase: lower_case
+  readability-identifier-naming.MemberIgnoredRegexp: '^([A-Z])$'
+  readability-identifier-naming.MethodCase: lower_case
+  readability-identifier-naming.MethodIgnoredRegexp: '^(.*[123][Ddf].*)$'
+  readability-identifier-naming.ParameterIgnoredRegexp: '^(_.*)$'
+  readability-identifier-naming.StructCase: CamelCase
+  readability-identifier-naming.VariableCase: aNy_CasE
+  readability-identifier-naming.VariableIgnoredRegexp: '^(_.*)$'
+  readability-identifier-naming.EnumCase: CamelCase
+  readability-identifier-naming.EnumConstantCase: UPPER_CASE

.github/workflows/clang-tidy-check.yml

@@ -0,0 +1,42 @@
+name: Clang-Tidy Check
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    paths:
+      - '.github/workflows/clang-tidy-check.yml'
+      - '.clang-tidy'
+      - 'src/**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+
+jobs:
+  clang-tidy:
+    name: Run Clang-Tidy
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y clang-tidy cmake build-essential
+
+      - name: Get number of CPU cores
+        uses: SimenB/[email protected]
+        id: cpu-cores
+
+      - name: Configure CMake
+        run: |
+          mkdir -p build
+          cd build
+          cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON ..
+
+      - name: Run Clang-Tidy
+        run: |
+          run-clang-tidy -quiet -j ${{ steps.cpu-cores.outputs.count }} -p build $(find src -name '*.cpp')

python/src/broad_phase/spatial_hash.cpp

@@ -69,7 +69,7 @@ void define_spatial_hash(py::module_& m)
             "voxel_count", &SpatialHash::voxel_count,
             "The number of voxels in each dimension.")
         .def_readwrite(
-            "one_div_voxelSize", &SpatialHash::one_div_voxelSize,
+            "one_div_voxel_size", &SpatialHash::one_div_voxel_size,
             "1.0 / voxel_size")
         .def_readwrite(
             "voxel_count_0x1", &SpatialHash::voxel_count_0x1,

python/src/candidates/candidates.cpp

@@ -12,7 +12,8 @@ void define_candidates(py::module_& m)
             "build",
             py::overload_cast<
                 const CollisionMesh&, Eigen::ConstRef<Eigen::MatrixXd>,
-                const double, std::shared_ptr<BroadPhase>>(&Candidates::build),
+                const double, const std::shared_ptr<BroadPhase>&>(
+                &Candidates::build),
             R"ipc_Qu8mg5v7(
             Initialize the set of discrete collision detection candidates.
 
@@ -29,7 +30,7 @@ void define_candidates(py::module_& m)
             py::overload_cast<
                 const CollisionMesh&, Eigen::ConstRef<Eigen::MatrixXd>,
                 Eigen::ConstRef<Eigen::MatrixXd>, const double,
-                std::shared_ptr<BroadPhase>>(&Candidates::build),
+                const std::shared_ptr<BroadPhase>&>(&Candidates::build),
             R"ipc_Qu8mg5v7(
             Initialize the set of continuous collision detection candidates.
 

python/src/collisions/normal/normal_collisions.cpp

@@ -12,7 +12,7 @@ void define_normal_collisions(py::module_& m)
             "build",
             py::overload_cast<
                 const CollisionMesh&, Eigen::ConstRef<Eigen::MatrixXd>,
-                const double, const double, std::shared_ptr<BroadPhase>>(
+                const double, const double, const std::shared_ptr<BroadPhase>&>(
                 &NormalCollisions::build),
             R"ipc_Qu8mg5v7(
             Initialize the set of collisions used to compute the barrier potential.

src/ipc/broad_phase/aabb.hpp

@@ -65,7 +65,7 @@ class AABB {
     /// @brief Maximum corner of the AABB.
     ArrayMax3d max;
     /// @brief Vertex IDs attached to the AABB.
-    std::array<index_t, 3> vertex_ids;
+    std::array<index_t, 3> vertex_ids = { { -1, -1, -1 } };
 };
 
 /// @brief Build one AABB per vertex position (row of V).

src/ipc/broad_phase/broad_phase.cpp

@@ -46,7 +46,7 @@ void BroadPhase::build(
     Eigen::ConstRef<Eigen::MatrixXi> edges,
     Eigen::ConstRef<Eigen::MatrixXi> faces)
 {
-    assert(vertex_boxes.size() > 0);
+    assert(!vertex_boxes.empty());
     assert(edges.size() == 0 || edges.cols() == 2);
     assert(faces.size() == 0 || faces.cols() == 3);
     build_edge_boxes(vertex_boxes, edges, edge_boxes);

src/ipc/broad_phase/broad_phase.hpp

@@ -114,7 +114,11 @@ class BroadPhase {
     virtual bool can_edge_face_collide(size_t ei, size_t fi) const;
     virtual bool can_faces_collide(size_t fai, size_t fbi) const;
 
-    static bool default_can_vertices_collide(size_t, size_t) { return true; }
+    static bool
+    default_can_vertices_collide(size_t /*unused*/, size_t /*unused*/)
+    {
+        return true;
+    }
 
     std::vector<AABB> vertex_boxes;
     std::vector<AABB> edge_boxes;

src/ipc/broad_phase/brute_force.cpp

@@ -22,7 +22,7 @@ void BruteForce::detect_candidates(
     tbb::enumerable_thread_specific<std::vector<Candidate>> storage;
 
     tbb::parallel_for(
-        tbb::blocked_range2d<size_t>(0ul, boxes0.size(), 0ul, boxes1.size()),
+        tbb::blocked_range2d<size_t>(0UL, boxes0.size(), 0UL, boxes1.size()),
         [&](const tbb::blocked_range2d<size_t>& r) {
             auto& local_candidates = storage.local();
 

src/ipc/broad_phase/bvh.cpp

@@ -33,7 +33,7 @@ void BVH::build(
 
 void BVH::init_bvh(const std::vector<AABB>& boxes, SimpleBVH::BVH& bvh)
 {
-    if (boxes.size() == 0) {
+    if (boxes.empty()) {
         return;
     }
 
@@ -101,7 +101,7 @@ void BVH::detect_candidates(
 void BVH::detect_vertex_vertex_candidates(
     std::vector<VertexVertexCandidate>& candidates) const
 {
-    if (vertex_boxes.size() == 0) {
+    if (vertex_boxes.empty()) {
         return;
     }
 
@@ -113,7 +113,7 @@ void BVH::detect_vertex_vertex_candidates(
 void BVH::detect_edge_vertex_candidates(
     std::vector<EdgeVertexCandidate>& candidates) const
 {
-    if (edge_boxes.size() == 0 || vertex_boxes.size() == 0) {
+    if (edge_boxes.empty() || vertex_boxes.empty()) {
         return;
     }
 
@@ -127,7 +127,7 @@ void BVH::detect_edge_vertex_candidates(
 void BVH::detect_edge_edge_candidates(
     std::vector<EdgeEdgeCandidate>& candidates) const
 {
-    if (edge_boxes.size() == 0) {
+    if (edge_boxes.empty()) {
         return;
     }
 
@@ -140,7 +140,7 @@ void BVH::detect_edge_edge_candidates(
 void BVH::detect_face_vertex_candidates(
     std::vector<FaceVertexCandidate>& candidates) const
 {
-    if (face_boxes.size() == 0 || vertex_boxes.size() == 0) {
+    if (face_boxes.empty() || vertex_boxes.empty()) {
         return;
     }
 
@@ -153,7 +153,7 @@ void BVH::detect_face_vertex_candidates(
 void BVH::detect_edge_face_candidates(
     std::vector<EdgeFaceCandidate>& candidates) const
 {
-    if (edge_boxes.size() == 0 || face_boxes.size() == 0) {
+    if (edge_boxes.empty() || face_boxes.empty()) {
         return;
     }
 
@@ -166,7 +166,7 @@ void BVH::detect_edge_face_candidates(
 void BVH::detect_face_face_candidates(
     std::vector<FaceFaceCandidate>& candidates) const
 {
-    if (face_boxes.size() == 0) {
+    if (face_boxes.empty()) {
         return;
     }