ci: add CPU-only C++ build coverage

.github/workflows/pr.yaml

@@ -15,6 +15,7 @@ jobs:
       - changed-files
       - checks
       - clang-tidy
+      - conda-cpp-build-cpu
       - conda-cpp-build
       - conda-cpp-tests
       - conda-cpp-checks
@@ -169,6 +170,23 @@ jobs:
       arch: "amd64"
       container_image: "rapidsai/ci-conda:26.06-latest"
       script: "ci/run_clang_tidy.sh"
+  conda-cpp-build-cpu:
+    needs: [checks, changed-files]
+    permissions:
+      actions: read
+      contents: read
+      id-token: write
+      packages: read
+      pull-requests: read
+    secrets: inherit # zizmor: ignore[secrets-inherit]
+    uses: rapidsai/shared-workflows/.github/workflows/custom-job.yaml@release/26.06
+    if: fromJSON(needs.changed-files.outputs.changed_file_groups).test_cpp
+    with:
+      build_type: pull-request
+      node_type: cpu16
+      arch: "amd64"
+      container_image: "rapidsai/ci-conda:26.06-latest"
+      script: "env NVFOREST_EXTRA_CMAKE_ARGS=-DNVFOREST_ENABLE_GPU=OFF ci/build_cpp.sh"
   conda-cpp-build:
     needs: checks
     permissions:

conda/recipes/libnvforest/recipe.yaml

@@ -40,6 +40,7 @@ cache:
         CMAKE_CXX_COMPILER_LAUNCHER: ${{ env.get("CMAKE_CXX_COMPILER_LAUNCHER") }}
         CMAKE_GENERATOR: ${{ env.get("CMAKE_GENERATOR") }}
         NVCC_APPEND_FLAGS: ${{ env.get("NVCC_APPEND_FLAGS", default="") }}
+        NVFOREST_EXTRA_CMAKE_ARGS: ${{ env.get("NVFOREST_EXTRA_CMAKE_ARGS", default="") }}
         PARALLEL_LEVEL: ${{ env.get("PARALLEL_LEVEL", default="8") }}
         RAPIDS_ARTIFACTS_DIR: ${{ env.get("RAPIDS_ARTIFACTS_DIR", default="") }}
         SCCACHE_BUCKET: ${{ env.get("SCCACHE_BUCKET", default="") }}

cpp/include/nvforest/exceptions.hpp

@@ -22,11 +22,11 @@ struct unusable_model_exception : std::exception {
 /** Exception indicating model import failed */
 struct model_import_error : std::exception {
   model_import_error() : model_import_error("Error while importing model") {}
-  model_import_error(char const* msg) : msg_{msg} {}
-  virtual char const* what() const noexcept { return msg_; }
+  model_import_error(std::string msg) : msg_{msg} {}
+  virtual char const* what() const noexcept { return msg_.c_str(); }
 
  private:
-  char const* msg_;
+  std::string msg_;
 };
 
 /**

cpp/include/nvforest/forest_model.hpp

@@ -11,6 +11,10 @@
 #include <nvforest/detail/raft_proto/handle.hpp>
 #include <nvforest/infer_kind.hpp>
 
+#ifdef NVFOREST_ENABLE_GPU
+#include <cuda_runtime_api.h>
+#endif
+
 #include <cstddef>
 #include <type_traits>
 #include <variant>
@@ -289,7 +293,11 @@ struct forest_model {
     int current_device_id;
     if (out_mem_type == raft_proto::device_type::gpu ||
         in_mem_type == raft_proto::device_type::gpu) {
+#ifdef NVFOREST_ENABLE_GPU
       raft_proto::cuda_check(cudaGetDevice(&current_device_id));
+#else
+      throw raft_proto::gpu_unsupported("Tried to use GPU memory in CPU-only build");
+#endif
     } else {
       current_device_id = -1;
     }

cpp/include/nvforest/treelite_importer.hpp

@@ -21,6 +21,7 @@
 #include <treelite/tree.h>
 
 #include <cmath>
+#include <string>
 #include <variant>
 
 namespace nvforest {
@@ -351,24 +352,34 @@ struct treelite_importer {
         *processed_tl_model.get(), align_bytes, use_double_precision, dev_type, device, stream);
     }
 
-    ASSERT(tl_model.num_target == 1, "nvForest does not support multi-target model");
+    if (tl_model.num_target != 1) {
+      throw model_import_error("nvForest does not support multi-target model");
+    }
     // Check tree annotation (assignment)
     if (tl_model.task_type == treelite::TaskType::kMultiClf) {
+      if (tl_model.num_class.Empty() || tl_model.num_class[0] <= 0) {
+        throw model_import_error("MultiClf model must define positive num_class");
+      }
       // Must be either vector leaf or grove-per-class
       if (tl_model.leaf_vector_shape[1] > 1) {  // vector-leaf
-        ASSERT(tl_model.leaf_vector_shape[1] == int(tl_model.num_class[0]),
-               "Vector leaf must be equal to num_class = %d",
-               tl_model.num_class[0]);
+        if (tl_model.leaf_vector_shape[1] != int(tl_model.num_class[0])) {
+          throw model_import_error("Vector leaf must be equal to num_class = " +
+                                   std::to_string(tl_model.num_class[0]));
+        }
         auto tree_count = num_trees(tl_model);
         for (decltype(tree_count) tree_id = 0; tree_id < tree_count; ++tree_id) {
-          ASSERT(tl_model.class_id[tree_id] == -1, "Tree %d has invalid class assignment", tree_id);
+          if (tl_model.class_id[tree_id] != -1) {
+            throw model_import_error("Tree " + std::to_string(tree_id) +
+                                     " has invalid class assignment");
+          }
         }
       } else {  // grove-per-class
         auto tree_count = num_trees(tl_model);
         for (decltype(tree_count) tree_id = 0; tree_id < tree_count; ++tree_id) {
-          ASSERT(tl_model.class_id[tree_id] == int(tree_id % tl_model.num_class[0]),
-                 "Tree %d has invalid class assignment",
-                 tree_id);
+          if (tl_model.class_id[tree_id] != int(tree_id % tl_model.num_class[0])) {
+            throw model_import_error("Tree " + std::to_string(tree_id) +
+                                     " has invalid class assignment");
+          }
         }
       }
     }

cpp/tests/treelite_importer.cpp

@@ -4,6 +4,7 @@
  */
 
 #include <nvforest/detail/raft_proto/device_type.hpp>
+#include <nvforest/detail/raft_proto/handle.hpp>
 #include <nvforest/postproc_ops.hpp>
 #include <nvforest/tree_layout.hpp>
 #include <nvforest/treelite_importer.hpp>
@@ -337,7 +338,12 @@ TEST(TreeliteImporter, DegenerateTree)
   auto fil_model = import_from_treelite_model(*tl_model, tree_layout::breadth_first);
   ASSERT_FALSE(fil_model.has_vector_leaves());
 
-  auto handle         = raft::handle_t{};
+#ifdef NVFOREST_ENABLE_GPU
+  auto raft_handle = raft::handle_t{};
+  auto handle      = raft_proto::handle_t{raft_handle};
+#else
+  auto handle = raft_proto::handle_t{};
+#endif
   auto X              = std::vector<double>{0.0};
   auto preds          = std::vector<double>(1, 0.0);
   auto expected_preds = std::vector<double>{1.0};
@@ -358,7 +364,12 @@ TEST(TreeliteImporter, DegenerateTreeWithVectorLeaf)
   auto fil_model = import_from_treelite_model(*tl_model, tree_layout::breadth_first);
   ASSERT_TRUE(fil_model.has_vector_leaves());
 
-  auto handle         = raft::handle_t{};
+#ifdef NVFOREST_ENABLE_GPU
+  auto raft_handle = raft::handle_t{};
+  auto handle      = raft_proto::handle_t{raft_handle};
+#else
+  auto handle = raft_proto::handle_t{};
+#endif
   auto X              = std::vector<double>{0.0};
   auto preds          = std::vector<double>(2, 0.0);
   auto expected_preds = std::vector<double>{0.5, 0.5};