KeyError: 'fields'

[vk@…]

How to Reproduce

While doing a GET operation on /ticket/49, Trac issued an internal error.

(please provide additional details here)

Request parameters:

{'action': u'diff', 'id': u'49', 'version': u'23'}

User Agent was: Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20100101 Firefox/8.0

System Information

Trac	0.11.7
Python	2.5.5 (r255:77872, Jun 3 2010, 14:43:28) [GCC 4.1.2 20080704 (Red Hat 4.1.2-48)]
setuptools	0.6c11
SQLite	3.6.23
pysqlite	2.3.2
Genshi	0.5.1
mod_wsgi	3.1 (WSGIProcessGroup tracdaemon WSGIApplicationGroup %{GLOBAL})
Pygments	1.3.1
Subversion	1.6.11 (r934486)
RPC	1.1.0-r7971
jQuery:	1.2.6

Python Traceback

Traceback (most recent call last):
  File "/usr/local/lib/python2.5/site-packages/Trac-0.11.7-py2.5.egg/trac/web/main.py", line 450, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.5/site-packages/Trac-0.11.7-py2.5.egg/trac/web/main.py", line 217, in dispatch
    self._post_process_request(req, *resp)
  File "/usr/local/lib/python2.5/site-packages/Trac-0.11.7-py2.5.egg/trac/web/main.py", line 309, in _post_process_request
    resp = f.post_process_request(req, *resp)
  File "/usr/local/lib/python2.5/site-packages/TracMasterTickets-2.1.3-py2.5.egg/mastertickets/web_ui.py", line 64, in post_process_request
    for field, field_data in change['fields'].iteritems():
KeyError: 'fields'

[Jun Omae]

PluginIssue (​th:MasterTicketsPlugin). It seems that the issue is the same as ​th:ticket:3920.