How to Reproduce

While doing a POST operation on /, Trac issued an internal error.

''(please provide additional details here)''

Request parameters:

{'__FORM_TOKEN': u'22f52b2760ea410970016e19',
 'recaptcha_challenge_field': u'03AHJ_Vusan9OFKEVe3hw24_fEpwH8F_jM62v6KKFq6FoPNlrE_9mdC_ktfDOyac9mGXg8RWaz_1s3acDHKmRj1EikVZvREa5qqp97t0rIViB9nLXNUNFawTGoDCU5LqplTxNmWezMT_YMNFMlgaXCeYJhwD0w8mGSIuc3a4o0BQ4NjGGw3Gwe5V4',
 'recaptcha_response_field': u'eatedaw unlimited'}

User agent: Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.81 Safari/537.1

System Information

''System information not available''

Enabled Plugins

''Plugin information not available''

Python Traceback

Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12.1-py2.6.egg/trac/web/main.py", line 511, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12.1-py2.6.egg/trac/web/main.py", line 202, in dispatch
    chosen_handler)
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12.1-py2.6.egg/trac/web/main.py", line 344, in _pre_process_request
    chosen_handler = filter_.pre_process_request(req, chosen_handler)
  File "/usr/local/lib/python2.6/dist-packages/TracSpamFilter-0.4.1dev_r10170-py2.6.egg/tracspamfilter/captcha/api.py", line 119, in pre_process_request
    del req.session['captcha_redirect']
KeyError: 'captcha_redirect'