Issue #22290: PyObject_Call() now fails with an assertion error when called

vstinner · vstinner · commit 8f4ec8d3ef9a · 2014-09-05T01:10:29.000+02:00
with an exception set. This new assertion helps to understand if the exception
was already set before calling the function or raised by the function.
diff --git a/Objects/abstract.c b/Objects/abstract.c
@@ -2074,6 +2074,11 @@ PyObject_Call(PyObject *func, PyObject *arg, PyObject *kw)
 {
     ternaryfunc call;
 
+    /* PyObject_Call() must not be called with an exception set,
+       because it may clear it (directly or indirectly) and so the
+       caller looses its exception */
+    assert(!PyErr_Occurred());
+
     if ((call = func->ob_type->tp_call) != NULL) {
         PyObject *result;
         if (Py_EnterRecursiveCall(" while calling a Python object"))
