bpo-45924: Fix asyncio incorrect traceback when future's exception is raised multiple times (GH-30274)

1 files changed, 14 insertions, 0 deletions

diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index bb7c5a7..46175cc 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -70,6 +70,7 @@ typedef enum {
     PyObject *prefix##_context0;                                            \
     PyObject *prefix##_callbacks;                                           \
     PyObject *prefix##_exception;                                           \
+    PyObject *prefix##_exception_tb;                                        \
     PyObject *prefix##_result;                                              \
     PyObject *prefix##_source_tb;                                           \
     PyObject *prefix##_cancel_msg;                                          \
@@ -495,6 +496,7 @@ future_init(FutureObj *fut, PyObject *loop)
     Py_CLEAR(fut->fut_callbacks);
     Py_CLEAR(fut->fut_result);
     Py_CLEAR(fut->fut_exception);
+    Py_CLEAR(fut->fut_exception_tb);
     Py_CLEAR(fut->fut_source_tb);
     Py_CLEAR(fut->fut_cancel_msg);
     Py_CLEAR(fut->fut_cancelled_exc);
@@ -601,7 +603,9 @@ future_set_exception(FutureObj *fut, PyObject *exc)
     }
 
     assert(!fut->fut_exception);
+    assert(!fut->fut_exception_tb);
     fut->fut_exception = exc_val;
+    fut->fut_exception_tb = PyException_GetTraceback(exc_val);
     fut->fut_state = STATE_FINISHED;
 
     if (future_schedule_callbacks(fut) == -1) {
@@ -656,8 +660,16 @@ future_get_result(FutureObj *fut, PyObject **result)
 
     fut->fut_log_tb = 0;
     if (fut->fut_exception != NULL) {
+        PyObject *tb = fut->fut_exception_tb;
+        if (tb == NULL) {
+            tb = Py_None;
+        }
+        if (PyException_SetTraceback(fut->fut_exception, tb) < 0) {
+            return -1;
+        }
         Py_INCREF(fut->fut_exception);
         *result = fut->fut_exception;
+        Py_CLEAR(fut->fut_exception_tb);
         return 1;
     }
 
@@ -799,6 +811,7 @@ FutureObj_clear(FutureObj *fut)
     Py_CLEAR(fut->fut_callbacks);
     Py_CLEAR(fut->fut_result);
     Py_CLEAR(fut->fut_exception);
+    Py_CLEAR(fut->fut_exception_tb);
     Py_CLEAR(fut->fut_source_tb);
     Py_CLEAR(fut->fut_cancel_msg);
     Py_CLEAR(fut->fut_cancelled_exc);
@@ -815,6 +828,7 @@ FutureObj_traverse(FutureObj *fut, visitproc visit, void *arg)
     Py_VISIT(fut->fut_callbacks);
     Py_VISIT(fut->fut_result);
     Py_VISIT(fut->fut_exception);
+    Py_VISIT(fut->fut_exception_tb);
     Py_VISIT(fut->fut_source_tb);
     Py_VISIT(fut->fut_cancel_msg);
     Py_VISIT(fut->fut_cancelled_exc);