SVN log messages can be None.

attract_server/subversion.py

@@ -40,6 +40,10 @@ class CommitLogObserver(object):
             # assumption: revisions are always logged in strictly increasing order.
             self.last_seen_revision = log_entry.revision
 
+            # Log entries can be None.
+            if not log_entry.msg:
+                continue
+
             # Parse the commit log to see if there are any task markers.
             lines = log_entry.msg.split('\n', 1)
             first_line = lines[0]