Created attachment 586281 [details]
patch

Description of problem:
When ibus-hunspell-table is enabled, typing key with unassigned keysym (NoSymbol) will cause crash.

Version-Release number of selected component (if applicable):
ibus-hunspell-table-0.0.6-1.fc17

How reproducible:
100%

Steps to Reproduce:
1. xmodmap -e "keycode 96 = NoSymbol"
2. enable "English - US(Hunspell)" engine in IBus menu
3. type F12
  
Actual results:
The engine process crashes with the following message:

 process 6891: Array or variant type requires that type string be written, but end_struct was written.
 The overall signature expected here was '(sa{sv}s(sa{sv}av))' and we are on byte 8 of that signature.
  D-Bus not built with -rdynamic so unable to print a backtrace

Expected results:
No crash.

Additional info:
I noticed this when using international keyboard with more keys than US keyboard.  Since IBus switches the system keyboard layout with "setxkbmap us", some keys (here "|") are unmapped.

It seems that ASCII range check in _table_mode_process_key_event() is fragile (patch attached).