feat(cython): Hide C++ stacktrace by default (#70)

This PR introduces an environment variable `MLC_SHOW_CPP_STACKTRACES`,
which controls if CXX-side stacktrace is included when an exception is
thrown. It's turned on only if it's value is `1`. It means C++
stacktrace is hidden by default.

Should fix #68.

Author: potatomashed

.github/workflows/ci.yml

@@ -5,6 +5,7 @@ env:
   CIBW_BUILD_VERBOSITY: 3
   CIBW_TEST_REQUIRES: "pytest torch"
   CIBW_TEST_COMMAND: "pytest -svv --durations=20 {project}/tests/python/"
+  CIBW_ENVIRONMENT: "MLC_SHOW_CPP_STACKTRACES=1"
   MLC_CIBW_VERSION: "2.22.0"
   MLC_PYTHON_VERSION: "3.9"
   MLC_CIBW_WIN_BUILD: "cp39-win_amd64"

python/mlc/_cython/__init__.py

@@ -27,6 +27,7 @@
 )
 from .core import (  # type: ignore[import-not-found]
     container_to_py,
+    cxx_stacktrace_enabled,
     device_as_pair,
     dtype_as_triple,
     dtype_from_triple,
@@ -50,6 +51,7 @@
     tensor_shape,
     tensor_strides,
     tensor_to_dlpack,
+    toggle_cxx_stacktrace,
     type_add_method,
     type_cast,
     type_create,

python/mlc/_cython/core.pyx

@@ -1,6 +1,7 @@
 # cython: language_level=3
 import ctypes
 import itertools
+import os
 from libcpp.vector cimport vector
 from libc.stdint cimport int8_t, int16_t, int32_t, int64_t, uint8_t, uint16_t, uint32_t, uint64_t
 from libc.stdlib cimport malloc, free
@@ -407,7 +408,13 @@ cdef class PyAny:
             func = _vtable_get_func_ptr(vtable, type_index, True)
         except Exception as e:  # no-cython-lint
             raise TypeError(f"Cannot find method `{name}` for type: {cls}") from e
-        _func_call_impl(func, args, &c_ret)
+        if CXX_STACKTRACE_ENABLED:
+            _func_call_impl(func, args, &c_ret)
+        else:
+            try:
+                _func_call_impl(func, args, &c_ret)
+            except Exception as e:  # no-cython-lint
+                raise e.with_traceback(None)
         return _any_c2py_no_inc_ref(c_ret)
 
 cdef class Str(str):
@@ -1699,6 +1706,16 @@ cpdef list type_table():
     return list(TYPE_INDEX_TO_INFO)
 
 
+cpdef void toggle_cxx_stacktrace(bint enable):
+    global CXX_STACKTRACE_ENABLED
+    CXX_STACKTRACE_ENABLED = enable
+
+
+cpdef bint cxx_stacktrace_enabled():
+    global CXX_STACKTRACE_ENABLED
+    return CXX_STACKTRACE_ENABLED
+
+
 cdef const char* _DLPACK_CAPSULE_NAME = "dltensor"
 cdef const char* _DLPACK_CAPSULE_NAME_USED = "used_dltensor"
 cdef const char* _DLPACK_CAPSULE_NAME_VER = "dltensor_versioned"
@@ -1735,3 +1752,4 @@ cdef MLCFunc* _OPAQUE_INIT = _vtable_get_func_ptr(_VTABLE_INIT, kMLCOpaque, Fals
 cdef MLCFunc* _TENSOR_INIT = _vtable_get_func_ptr(_vtable_get_global(b"__init_DLManagedTensor"), kMLCTensor, False)
 cdef MLCFunc* _TENSOR_INIT_VER = _vtable_get_func_ptr(_vtable_get_global(b"__init_DLManagedTensorVersioned"), kMLCTensor, False)  # no-cython-lint
 cdef tuple _OPAQUE_TYPES = ()
+cdef bint CXX_STACKTRACE_ENABLED = os.environ.get("MLC_SHOW_CPP_STACKTRACES", "0") == "1"

python/mlc/core/func.py

@@ -3,7 +3,14 @@
 from collections.abc import Callable
 from typing import Any, TypeVar
 
-from mlc._cython import c_class_core, func_call, func_get, func_init, func_register
+from mlc._cython import (
+    c_class_core,
+    cxx_stacktrace_enabled,
+    func_call,
+    func_get,
+    func_init,
+    func_register,
+)
 
 from .object import Object
 
@@ -17,7 +24,13 @@ def __init__(self, func: Callable) -> None:
         func_init(self, func)
 
     def __call__(self, *args: Any) -> Any:
-        return func_call(self, args)
+        if cxx_stacktrace_enabled():
+            return func_call(self, args)
+        else:
+            try:
+                return func_call(self, args)
+            except Exception as e:
+                raise e.with_traceback(None)
 
     @staticmethod
     def get(name: str, allow_missing: bool = False) -> Func: