More robust handling of argument indices in message extraction.

diff --git a/babel/messages/extract.py b/babel/messages/extract.py
index 39810923b957ce9a35c3ba894a13d7dfb26de352..da0063c260e744607468d6d163a86fe3d1ab74d5 100644 (file)
--- a/babel/messages/extract.py
+++ b/babel/messages/extract.py
@@ -220,7 +220,7 @@ def extract(method, fileobj, keywords=DEFAULT_KEYWORDS, comment_tags=(),
         for lineno, funcname, messages, comments in results:
             if isinstance(messages, (list, tuple)):
                 msgs = []
-                for index in keywords[funcname]:
+                for index in keywords[funcname] or (1,):
                     msgs.append(messages[index - 1])
                 messages = tuple(msgs)
                 if len(messages) == 1: