[FIX]: cuda.core: simplify _check_runtime_error logic (#2003)

* cuda.core: prefer binding names for runtime errors

Use the generated runtime error enum as the name source for known CUDA Runtime errors so error messages remain stable when the runtime name table differs from the installed bindings.

Made-with: Cursor

* cuda.core: simplify runtime error naming path

`_check_error()` only routes `runtime.cudaError_t` instances into
`_check_runtime_error()`, so consulting `cudaGetErrorName()` and keeping a
fallback for unknown values does not improve the normal `cuda.core` path. The
Windows hybrid cudart issue is that the runtime name table can lag the
generated enum table, so using `error.name` directly is both simpler and a
better match for the values the code already has.

With the runtime path now relying on enum members, the runtime-side tests no
longer need to account for `UNEXPECTED ERROR CODE` in this loop or keep a
separate monkeypatch test for avoiding the runtime name lookup.

Made-with: Cursor

Author: rwgk

cuda_core/cuda/core/_utils/cuda_utils.pyx

@@ -171,10 +171,9 @@ cpdef inline int _check_driver_error(cydriver.CUresult error) except?-1 nogil:
 cpdef inline int _check_runtime_error(error) except?-1:
     if error == _RUNTIME_SUCCESS:
         return 0
-    name_err, name = runtime.cudaGetErrorName(error)
-    if name_err != _RUNTIME_SUCCESS:
-        raise CUDAError(f"UNEXPECTED ERROR CODE: {error}")
-    name = name.decode()
+    # `_check_error()` reaches this path only for `runtime.cudaError_t` values.
+    # Use the enum name directly because Windows hybrid cudart can lag that table.
+    name = error.name
     expl = RUNTIME_CUDA_ERROR_EXPLANATIONS.get(int(error))
     if expl is not None:
         raise CUDAError(f"{name}: {expl}")

cuda_core/tests/test_cuda_utils.py

@@ -48,22 +48,14 @@ def test_check_driver_error():
 
 
 def test_check_runtime_error():
-    num_unexpected = 0
     for error in runtime.cudaError_t:
         if error == runtime.cudaError_t.cudaSuccess:
             assert cuda_utils._check_runtime_error(error) == 0
         else:
             with pytest.raises(cuda_utils.CUDAError) as e:
                 cuda_utils._check_runtime_error(error)
             msg = str(e)
-            if "UNEXPECTED ERROR CODE" in msg:
-                num_unexpected += 1
-            else:
-                # Example repr(error): <cudaError_t.cudaErrorUnknown: 999>
-                enum_name = repr(error).split(".", 1)[1].split(":", 1)[0]
-                assert enum_name in msg
-    # Smoke test: We don't want most to be unexpected.
-    assert num_unexpected < len(driver.CUresult) * 0.5
+            assert error.name in msg
 
 
 def test_driver_error_enum_has_non_empty_docstring():