"KeyError: captcha_redirect" after logging in during captcha

[anonymous]

Steps to reproduce:

1. Log out of Trac
2. Attempt to add a comment on a ticket. (This redirects to captcha.)
3. Log in. (This returns user to captcha page.)
4. Submit captcha

Expected result: Comment submits successfully on step 4, or user is redirected to a non-captcha page on step 3.

Actual result:

2010-10-17 19:47:53,709 Trac[main] ERROR: Internal Server Error:
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12-py2.6.egg/trac/web/main.py", line 513, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12-py2.6.egg/trac/web/main.py", line 200, in dispatch
    chosen_handler)
  File "/usr/local/lib/python2.6/dist-packages/Trac-0.12-py2.6.egg/trac/web/main.py", line 346, 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'

[anonymous]

In r10276.

[Remy Blank]

You should rather use the in operator to check for a key in a dictionary:

if 'captcha_redirect' in req.session: 
    del req.session['captcha_redirect']