gh-128799: Add frame of except* to traceback when wrapping a naked exception

Author: iritkatriel

Include/internal/pycore_ceval.h

@@ -264,7 +264,7 @@ PyAPI_DATA(const size_t) _Py_FunctionAttributeOffsets[];
 
 PyAPI_FUNC(int) _PyEval_CheckExceptStarTypeValid(PyThreadState *tstate, PyObject* right);
 PyAPI_FUNC(int) _PyEval_CheckExceptTypeValid(PyThreadState *tstate, PyObject* right);
-PyAPI_FUNC(int) _PyEval_ExceptionGroupMatch(PyObject* exc_value, PyObject *match_type, PyObject **match, PyObject **rest);
+PyAPI_FUNC(int) _PyEval_ExceptionGroupMatch(_PyInterpreterFrame *, PyObject* exc_value, PyObject *match_type, PyObject **match, PyObject **rest);
 PyAPI_FUNC(void) _PyEval_FormatAwaitableError(PyThreadState *tstate, PyTypeObject *type, int oparg);
 PyAPI_FUNC(void) _PyEval_FormatExcCheckArg(PyThreadState *tstate, PyObject *exc, const char *format_str, PyObject *obj);
 PyAPI_FUNC(void) _PyEval_FormatExcUnbound(PyThreadState *tstate, PyCodeObject *co, int oparg);

Misc/NEWS.d/next/Core_and_Builtins/2025-01-18-01-06-58.gh-issue-128799.vSNagk.rst

@@ -0,0 +1 @@
+Add frame of `except*` to traceback when it wraps a naked exception.

Python/bytecodes.c

@@ -2717,7 +2717,7 @@ dummy_func(
 
             PyObject *match_o = NULL;
             PyObject *rest_o = NULL;
-            int res = _PyEval_ExceptionGroupMatch(exc_value, match_type,
+            int res = _PyEval_ExceptionGroupMatch(frame, exc_value, match_type,
                                                   &match_o, &rest_o);
             DECREF_INPUTS();
             ERROR_IF(res < 0, error);

Python/ceval.c

@@ -27,6 +27,7 @@
 #include "pycore_range.h"         // _PyRangeIterObject
 #include "pycore_setobject.h"     // _PySet_Update()
 #include "pycore_sliceobject.h"   // _PyBuildSlice_ConsumeRefs
+#include "pycore_traceback.h"     // _PyTraceBack_FromFrame
 #include "pycore_tuple.h"         // _PyTuple_ITEMS()
 #include "pycore_uop_ids.h"       // Uops
 #include "pycore_pyerrors.h"
@@ -2094,8 +2095,8 @@ do_raise(PyThreadState *tstate, PyObject *exc, PyObject *cause)
 */
 
 int
-_PyEval_ExceptionGroupMatch(PyObject* exc_value, PyObject *match_type,
-                            PyObject **match, PyObject **rest)
+_PyEval_ExceptionGroupMatch(_PyInterpreterFrame *frame, PyObject* exc_value,
+                            PyObject *match_type, PyObject **match, PyObject **rest)
 {
     if (Py_IsNone(exc_value)) {
         *match = Py_NewRef(Py_None);
@@ -2121,6 +2122,15 @@ _PyEval_ExceptionGroupMatch(PyObject* exc_value, PyObject *match_type,
             if (wrapped == NULL) {
                 return -1;
             }
+            PyFrameObject *f = _PyFrame_GetFrameObject(frame);
+            if (f != NULL) {
+                PyObject *tb = _PyTraceBack_FromFrame(NULL, f);
+                if (tb == NULL) {
+                    return -1;
+                }
+                PyException_SetTraceback(wrapped, tb);
+                Py_DECREF(tb);
+            }
             *match = wrapped;
         }
         *rest = Py_NewRef(Py_None);