Preference window of kupfer doesn't open

[Johannes]

I could not get to the preference window and only get the following error when I started kupfer from a terminal:
kupfer
Kupfer: A free software (GPLv3+) launcher
 Copyright © 2007--2011 Ulrik Sverdrup with others
 http://kaizer.se/wiki/kupfer/

[kupfer.core.sources] SourcePickler: Error loading /home/johannes/.cache/kupfer/kOqeQrgq3epiIo0mjl6AuSw-v4.pickle.gz:
Traceback (most recent call last):
  File "/usr/share/kupfer/kupfer/icons.py", line 256, in _setup_icon_renderer
    _icon_render_change(setctl)
  File "/usr/share/kupfer/kupfer/icons.py", line 260, in _icon_render_change
    renderer_dict = setctl.get_preferred_alternative('icon_renderer')
  File "/usr/share/kupfer/kupfer/core/settings.py", line 410, in get_preferred_alternative
    alternatives = self._alternatives[category_key]
KeyError: 'icon_renderer'
/usr/share/kupfer/kupfer/ui/browser.py:2087: Warning: g_object_set_qdata: assertion `G_IS_OBJECT (object)' failed
  self.window.realize()
/usr/share/kupfer/kupfer/ui/browser.py:636: Warning: g_object_set_qdata: assertion `G_IS_OBJECT (object)' failed
  requisition.width, requisition.height = self.__child.size_request ()

** (kupfer.py:9616): CRITICAL **: cr_parser_new_from_buf: assertion `a_buf && a_len' failed

** (kupfer.py:9616): CRITICAL **: cr_parser_set_sac_handler: assertion `a_this' failed

(kupfer.py:9616): librsvg-WARNING **: Error setting CSS SAC handler

** (kupfer.py:9616): CRITICAL **: cr_parser_destroy: assertion `a_this && PRIVATE (a_this)' failed
[kupfer.ui.browser] WindowController: Trying to register <Super>space to spawn kupfer.. success

** (kupfer.py:9616): CRITICAL **: cr_parser_new_from_buf: assertion `a_buf && a_len' failed

** (kupfer.py:9616): CRITICAL **: cr_parser_set_sac_handler: assertion `a_this' failed

(kupfer.py:9616): librsvg-WARNING **: Error setting CSS SAC handler

** (kupfer.py:9616): CRITICAL **: cr_parser_destroy: assertion `a_this && PRIVATE (a_this)' failed

** (kupfer.py:9616): CRITICAL **: cr_parser_new_from_buf: assertion `a_buf && a_len' failed

** (kupfer.py:9616): CRITICAL **: cr_parser_set_sac_handler: assertion `a_this' failed

(kupfer.py:9616): librsvg-WARNING **: Error setting CSS SAC handler

** (kupfer.py:9616): CRITICAL **: cr_parser_destroy: assertion `a_this && PRIVATE (a_this)' failed
Traceback (most recent call last):
  File "/usr/share/kupfer/kupfer/ui/browser.py", line 1885, in mitem_handler
    callback(ui_ctx)
  File "/usr/share/kupfer/kupfer/kupferui.py", line 62, in show_preferences
    win = preferences.GetPreferencesWindowController()
  File "/usr/share/kupfer/kupfer/ui/preferences.py", line 875, in GetPreferencesWindowController
    _preferences_window = PreferencesWindowController()
  File "/usr/share/kupfer/kupfer/ui/preferences.py", line 119, in __init__
    self._update_alternative_combobox('terminal', terminal_combobox)
  File "/usr/share/kupfer/kupfer/ui/preferences.py", line 783, in _update_alternative_combobox
    setctl.get_valid_alternative_ids(category_key), key=lambda t:t[1])
  File "/usr/share/kupfer/kupfer/utils.py", line 77, in locale_sort
    seq = seq if isinstance(seq, list) else list(seq)
  File "/usr/share/kupfer/kupfer/core/settings.py", line 396, in get_valid_alternative_ids
    validator = self._alternative_validators[category_key]
KeyError: 'terminal'

Don't know if this is probably already reported but I didn't find the exact error message.

[David Schneider (dnschneid)]

This is a guess as I'm not familiar with the code there, but it sounds like Kupfer couldn't find any candidates for a terminal emulator on your system. What do you use for a terminal?

This will probably work as a workaround:
in file /usr/share/kupfer/kupfer/core/settings.py, add the following line at line 396 (the line right after the """s for get_valid_alternative_ids):

if not category_key in self._alternative_validators: return

The equivalent patch is attached, although this doesn't address the issue that Kupfer wasn't able to find a terminal. You'll have to configure it yourself using the Custom Terminal plugin.

[Johannes (j-hannes)]

I use Xfce and therefore I use the xfce-terminal
terminal --version
terminal 0.4.8 (Xfce 4.8.0)

Copyright (c) 2003-2011
 The Xfce development team. All rights reserved.

Written by Benedikt Meurer <email address hidden>
and Nick Schermer <email address hidden>.

Please report bugs to <http://bugzilla.xfce.org/>.

Don't know if there's something special about it.

[Johannes (j-hannes)]

btw thanks for your help

[Johannes (j-hannes)]

Also the proposed patch works, just tried it and it does indeed solve my problem.

[David Schneider (dnschneid)]

Ah, yeah, we've seen that problem before (on IRC, I think).
Kupfer expects the Debian (or at least Ubuntu's) packaging of xfce, which has it as xfce4-terminal, so it doesn't have "terminal" in its database.
What Kupfer should really have is a fallback on Debian's alternatives or mime or whatever more standard ways of discovering terminal emulators there are.

At a minimum, at least, Kupfer won't crash with this patch :)