Error downloading ticket attachment

[daved@…]

When I try to download the following attachment: http://projects.edgewall.com/trac/attachment/ticket/1682/TraciWyg-0.5-py2.4.egg?format=raw

I get the error:

Traceback (most recent call last):
  File "/usr/lib/python2.3/site-packages/trac/web/main.py", line 299, in dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.3/site-packages/trac/web/main.py", line 189, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/lib/python2.3/site-packages/trac/attachment.py", line 289, in process_request
    self._render_view(req, attachment)
  File "/usr/lib/python2.3/site-packages/trac/attachment.py", line 444, in _render_view
    if 'charset=' not in mime_type:
TypeError: iterable argument required

[anonymous]

Dup of #3073.