= bug description =
There is an issue with the ticketing component (https://fedorahosted.org/security-spin/report/1) of the Security Spin trac instance.

When somebody wants to read a ticket, trac says
{{{Trac detected an internal error:

TypeError: argument of type 'NoneType' is not iterable

}}}

and the traceback

{{{File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 525, in _dispatch_request
dispatcher.dispatch(req)
File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 267, in dispatch
content_type)
File "/usr/lib/python2.6/site-packages/trac/web/chrome.py", line 841, in render_template
stream |= self._filter_stream(req, method, filename, stream, data)
File "/usr/lib/python2.6/site-packages/Genshi-0.6-py2.6.egg/genshi/core.py", line 132, in or
return Stream(_ensure(function(self)), serializer=self.serializer)
File "/usr/lib/python2.6/site-packages/trac/web/chrome.py", line 997, in inner
data)
File "/usr/lib/python2.6/site-packages/tracvatar/web_ui.py", line 48, in filter_stream
self._lookup_email(author_data)
File "/usr/lib/python2.6/site-packages/tracvatar/web_ui.py", line 240, in _lookup_email
lookup_authors = sorted([a for a in author_data if '@' not in a])}}

Some sample tickets where the issue occurs:

• https://fedorahosted.org/security-spin/ticket/73
• https://fedorahosted.org/security-spin/ticket/71
• https://fedorahosted.org/security-spin/ticket/67
• https://fedorahosted.org/security-spin/ticket/65

This doesn't affect on all tickets. Newer tickets are working fine.

Thanks for taking a look.