--- a/hgext/convert/common.py	Sat Feb 02 21:01:43 2008 +0100
+++ b/hgext/convert/common.py	Sun Feb 03 21:47:07 2008 -0200
@@ -30,8 +30,8 @@
 class commit(object):
     def __init__(self, author, date, desc, parents, branch=None, rev=None,
                  extra={}):
-        self.author = author
-        self.date = date
+        self.author = author or 'unknown'
+        self.date = date or '0 0'
         self.desc = desc
         self.parents = parents
         self.branch = branch