Issue #18408: Fix PyErr_NormalizeException(), handle PyObject_IsSubclass() failure

vstinner · vstinner · commit 74a7fa66639b · 2013-07-17T00:44:53.000+02:00
PyObject_IsSubclass() can fail and raise a new exception!
diff --git a/Python/errors.c b/Python/errors.c
@@ -227,12 +227,21 @@ PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb)
        value will be an instance.
     */
     if (PyExceptionClass_Check(type)) {
+        int is_subclass;
+        if (inclass) {
+            is_subclass = PyObject_IsSubclass(inclass, type);
+            if (is_subclass < 0)
+                goto finally;
+        }
+        else
+            is_subclass = 0;
+
         /* if the value was not an instance, or is not an instance
            whose class is (or is derived from) type, then use the
            value as an argument to instantiation of the type
            class.
         */
-        if (!inclass || !PyObject_IsSubclass(inclass, type)) {
+        if (!inclass || !is_subclass) {
             PyObject *args, *res;
 
             if (value == Py_None)
