complain when there's no last exception

diff --git a/Lib/traceback.py b/Lib/traceback.py
index 3d877ee1502b38281c76d30c373993602e40f62f..b06fcea79618529e17bd8a8e83a8ed54b3e6d26d 100644 (file)
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -241,6 +241,8 @@ def format_exc(limit=None):
 def print_last(limit=None, file=None):
     """This is a shorthand for 'print_exception(sys.last_type,
     sys.last_value, sys.last_traceback, limit, file)'."""
+    if not hasattr(sys, "last_type"):
+        raise ValueError("no last exception")
     if file is None:
         file = sys.stderr
     print_exception(sys.last_type, sys.last_value, sys.last_traceback,