gh-128799: Add frame of except* to traceback when wrapping a naked exception (#128971)

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);

Lib/test/test_traceback.py

@@ -2937,6 +2937,33 @@ class BaseExceptionReportingTests:
         report = self.get_report(exc)
         self.assertEqual(report, expected)
 
+    def test_exception_group_wrapped_naked(self):
+        # See gh-128799
+
+        def exc():
+            try:
+                raise Exception(42)
+            except* Exception as e:
+                raise
+
+        expected = (f'  + Exception Group Traceback (most recent call last):\n'
+                    f'  |   File "{__file__}", line {self.callable_line}, in get_exception\n'
+                    f'  |     exception_or_callable()\n'
+                    f'  |     ~~~~~~~~~~~~~~~~~~~~~^^\n'
+                    f'  |   File "{__file__}", line {exc.__code__.co_firstlineno + 3}, in exc\n'
+                    f'  |     except* Exception as e:\n'
+                    f'  |         raise\n'
+                    f'  | ExceptionGroup:  (1 sub-exception)\n'
+                    f'  +-+---------------- 1 ----------------\n'
+                    f'    | Traceback (most recent call last):\n'
+                    f'    |   File "{__file__}", line {exc.__code__.co_firstlineno + 2}, in exc\n'
+                    f'    |     raise Exception(42)\n'
+                    f'    | Exception: 42\n'
+                    f'    +------------------------------------\n')
+
+        report = self.get_report(exc)
+        self.assertEqual(report, expected)
+
     def test_KeyboardInterrupt_at_first_line_of_frame(self):
         # see GH-93249
         def f():

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"
@@ -2074,8 +2075,8 @@ raise_error:
 */
 
 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);
@@ -2101,6 +2102,15 @@ _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);

Python/executor_cases.c.h

@@ -3452,7 +3452,7 @@
             PyObject *match_o = NULL;
             PyObject *rest_o = NULL;
             _PyFrame_SetStackPointer(frame, stack_pointer);
-            int res = _PyEval_ExceptionGroupMatch(exc_value, match_type,
+            int res = _PyEval_ExceptionGroupMatch(frame, exc_value, match_type,
                 &match_o, &rest_o);
             stack_pointer = _PyFrame_GetStackPointer(frame);
             PyStackRef_CLOSE(exc_value_st);

Python/generated_cases.c.h

@@ -3201,7 +3201,7 @@
             PyObject *match_o = NULL;
             PyObject *rest_o = NULL;
             _PyFrame_SetStackPointer(frame, stack_pointer);
-            int res = _PyEval_ExceptionGroupMatch(exc_value, match_type,
+            int res = _PyEval_ExceptionGroupMatch(frame, exc_value, match_type,
                 &match_o, &rest_o);
             stack_pointer = _PyFrame_GetStackPointer(frame);
             PyStackRef_CLOSE(exc_value_st);