AttributeError: 'list' object has no attribute 'lower'

[Ryan J Ollos]

Found in the logs:

[pid 25608 140573411886848] 2016-02-04 18:19:12,083 Trac[main] ERROR: Internal Server Error: <RequestWithSession "GET '/browser/trunk/trac/ticket/model.py?rev=6512&rev=6512'">, referrer None
Traceback (most recent call last):
  File "/usr/local/virtualenv/1.1dev/lib/python2.7/site-packages/trac/web/main.py", line 607, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/virtualenv/1.1dev/lib/python2.7/site-packages/trac/web/main.py", line 256, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/local/virtualenv/1.1dev/lib/python2.7/site-packages/trac/versioncontrol/web_ui/browser.py", line 335, in process_request
    if rev.lower() in ('', 'head'):
AttributeError: 'list' object has no attribute 'lower'

I recall Jun reporting a similar issue with duplicated arguments. I'll need to search for that.