Improved error classes

Author: ankane

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## 0.22.0 (unreleased)
 
 - Updated LibTorch to 2.9.0
+- Improved error classes
 
 ## 0.21.0 (2025-08-07)
 

ext/torch/ext.cpp

@@ -16,10 +16,14 @@ void init_generator(Rice::Module& m, Rice::Class& rb_cGenerator);
 void init_ivalue(Rice::Module& m, Rice::Class& rb_cIValue);
 void init_random(Rice::Module& m);
 
+VALUE rb_eTorchError = Qnil;
+
 extern "C"
 void Init_ext() {
   auto m = Rice::define_module("Torch");
 
+  rb_eTorchError = Rice::define_class_under(m, "Error", rb_eStandardError);
+
   // need to define certain classes up front to keep Rice happy
   auto rb_cIValue = Rice::define_class_under<torch::IValue>(m, "IValue")
     .define_constructor(Rice::Constructor<torch::IValue>());

ext/torch/templates.h

@@ -31,7 +31,7 @@ using torch::nn::init::NonlinearityType;
 
 #define END_HANDLE_TH_ERRORS                                         \
   } catch (const torch::Error& ex) {                                 \
-    rb_raise(rb_eRuntimeError, "%s", ex.what_without_backtrace());   \
+    rb_raise(rb_eTorchError, "%s", ex.what_without_backtrace());   \
   } catch (const Rice::Exception& ex) {                              \
     rb_raise(ex.class_of(), "%s", ex.what());                        \
   } catch (const std::exception& ex) {                               \

ext/torch/utils.h

@@ -12,8 +12,10 @@ static_assert(
   "Incompatible LibTorch version"
 );
 
+extern VALUE rb_eTorchError;
+
 inline void handle_global_error(const torch::Error& ex) {
-  throw Rice::Exception(rb_eRuntimeError, ex.what_without_backtrace());
+  throw Rice::Exception(rb_eTorchError, ex.what_without_backtrace());
 }
 
 // keep THP prefix for now to make it easier to compare code

lib/torch.rb

@@ -210,7 +210,6 @@
 require_relative "torch/hub"
 
 module Torch
-  class Error < StandardError; end
   class NotImplementedYet < StandardError
     def message
       "This feature has not been implemented yet. Consider submitting a PR."

test/torch_test.rb

@@ -66,17 +66,15 @@ def test_tutorial
     assert_kind_of Numo::SFloat, b
   end
 
-  # TODO use Torch::Error
   def test_friendly_error_tensor_no_cpp_trace
-    error = assert_raises(RuntimeError) do
+    error = assert_raises(Torch::Error) do
       Torch.arange(0, 100).view([10, 10]).select(2, 0)
     end
     assert_equal "Dimension out of range (expected to be in range of [-2, 1], but got 2)", error.message
   end
 
-  # TODO use Torch::Error
   def test_friendly_error_torch_no_cpp_trace
-    error = assert_raises(RuntimeError) do
+    error = assert_raises(Torch::Error) do
       Torch.select(Torch.arange(0, 100).view([10, 10]), 2, 0)
     end
     assert_equal "Dimension out of range (expected to be in range of [-2, 1], but got 2)", error.message