Sugar craches during undo for the first Keyboard component startup

[alsroot]

|TestCase|
* remove all gconf options for desktop/sugar/peripherals/keyboard
* open Keyboard control panel component
* click Cancel button
* sugar crashes due to None value for self._group_switch_option in Keyboard.undo()

Also Keyboard doesn't handle initial values for self._klayouts properly.

[sayamindu]

Proposed fix

[sayamindu]

The proposed patch checks for None value in each *_set() method in the model.

However, it also reduces the APPLY_TIMEOUT value to .5 second, as in some cases, even after an undo, the changed selection would kick in (if the undo was done within 3 seconds of the last layout selection change).

[alsroot]

after applying patch, there is one undo issue

|TestCase|
* remove all gconf options for desktop/sugar/peripherals/keyboard
* start sugar and open Keyboard component
* change all parameters
* click cancel button
* open Keyboard again
* "Key(s) to change layout" has chosen value from previous session

[sayamindu]

Slightly updated patch to handle the Options problem.

[sayamindu]

Replying to alsroot:

after applying patch, there is one undo issue

|TestCase|
* remove all gconf options for desktop/sugar/peripherals/keyboard
* start sugar and open Keyboard component
* change all parameters
* click cancel button
* open Keyboard again
* "Key(s) to change layout" has chosen value from previous session

Good catch!! Could you see if the second patch fixes this ?

[alsroot]

it still has problem with "Key(s) to change layout"

[alsroot]

 http://git.sugarlabs.org/projects/sugar/repos/mainline/commits/aac27244f0afa012bdac7d5a89e72b59dbb84a76

[alsroot]

 http://git.sugarlabs.org/projects/sugar/repos/mainline/commits/522116f3cb21a9fbbea273c1d4c06adb60dfedaa

[sayamindu]

Our patching have exposed a few more bugs.

1. During startup, the model may get set to , which causes havoc with the other XKB settings as well

2. In certain situations, model may get set as None or and so on, and we need to take care of those values.

[sayamindu]

Patch to fix the new issues

[tomeu]

Patch looks good to me, but if the user visible effect of the patch doesn't matches this ticket any more, would be better to open new tickets. Please push, thanks!