Issue #18408: PyObject_Call() now fails with an assertion error in debug mode

if the function called failed whereas no exception was raised, to detect bugs
earlier.

diff --git a/Objects/abstract.c b/Objects/abstract.c
index 244dcafc4b2b71ff9ebcc7ebb02b206e2ed5450d..6896600ebab21f93bb72dac763a02bf3002023ef 100644 (file)
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2104,10 +2104,16 @@ PyObject_Call(PyObject *func, PyObject *arg, PyObject *kw)
             return NULL;
         result = (*call)(func, arg, kw);
         Py_LeaveRecursiveCall();
-        if (result == NULL && !PyErr_Occurred())
+#ifdef NDEBUG
+        if (result == NULL && !PyErr_Occurred()) {
             PyErr_SetString(
                 PyExc_SystemError,
                 "NULL result without error in PyObject_Call");
+        }
+#else
+        if (result == NULL)
+            assert(PyErr_Occurred());
+#endif
         return result;
     }
     PyErr_Format(PyExc_TypeError, "'%.200s' object is not callable",