Back/forward crash

[Gnurou]

As reported by Kyle Davis:

I sometimes use the program as a running list for vocab I've come across but haven't committed to memory yet. Because of this, when I lose the bottom-pane history, it's like losing a little bit of work. Obviously the language itself isn't going anywhere and I'll come across the content again.

To reproduce the crash:

 - start a new instance of Tagaini Jisho 0.2.5 on Vista.
 - search for something that will produce no results, like "*耿*".
 - search for something that will produce results, like "*虻*".
 - click the "back" button in the search pane. This will clear the "*虻*" results.
 - click somewhere in the now-empty search results pane. This should gray out both the forward and back buttons for the search pane.
 - search for something that will produce results, like "*虻*".
 - crash.

[Gnurou (gnurou)]

There are actually two bugs here (possibly three):

1) clicking on the empty search results pane clears the search history out
2) a regexp-related crash that seems similar to the one in #567058

and

3) the user loses the search and detailed view history when the program crashes (which does not happen often, but is always frustrating anyway). Saving the search history in the database or config file (latter may not be practicable) sounds like a good idea.

[Misaki (myjunkmail311006)]

Related testing for this and bug #567058

Oddly, found a new way to crash! Using 0.2.6.2 under Ubuntu 10.4/Gnome.

1) - start a new instance of Tagaini Jisho.
2) - search for something that will produce no results, like "*耿*".
3) - search for something that will produce results, like "*虻*".
4)** - scroll in the results window, among the results.
5) - click the "back" button in the search pane. This will clear the "*虻*" results.
6) - click somewhere in the now-empty search results pane. Tagaini should crash.

Trying to replicate situations where Tagaini crashes without scrolling in the results window and instead bypassing step 4, but while this was happening several times couldn't get it to consistently happen. Could not exactly replicate the described crash of happening upon the third search result. Tried different methods of selecting search box other than Ctrl-L to replicate the crash without step 4 but without success.

- this pattern of crashing was done by copy-pasting the queries from this bug report.
- waiting 3~5 seconds after the (very short) query is complete before each action
- scrolling in step 4, and then selecting the search box, and then scrolling more (mouse/touchpad scroll without focusing the search results) before pressing the "back" button prevents the crash in step 6.
- using 「ひ」　for the second query also causes a crash with the described actions.

Other testing for the crash related to interrupting the database thread, as well as the clearing of search history:

It seems that the clearing of search history in the "forward" direction, after navigating back in search results, is due to the ordering in the list that shows up by pressing the arrow to the right of search results. From simple testing, it seems that the ordering of this list is updated either when the arrow is pressed to show the results; or when interacting with the search results. The current search is moved to the top, UNLESS it is already at the top, and at the search is performed again. This means with the search pattern
  1) - search for 「＊す＊」, wait to finish
  2) - search for 「ひ」, wait to finish
  3) - search for 「＊す＊」 again, wait to finish
  4) - back one in history to ひ, wait to finish (fast)
  5) - back again in history to ＊す＊, and while search is still underway (~17k results) scroll in results pane. Since it's already at the top of the list of search results, forward history will not be cleared and the search will not be interrupted and re-started, which would cause a crash.

Further describing this, going forward once more to ひ and pressing the search history arrow to the right of the search field will cause the current search to (very quickly) be re-performed, while the selection for the list of search results will remain on the previous top (＊す＊ in this case), despite that it is not the current displayed result. Pressing the arrow twice more, once to close and once more to reopen, will correctly show the current result at the top but the forward history has been removed due to the search having been performed again.

The final reason for a crash from the search results (at least in Ubuntu) is that changing focus away from Tagaini also causes ...