[wxruby-users] Segfault with GridCellChoiceEditor

[Glen Holcomb]

On Tue, Jul 29, 2008 at 7:28 AM, Glen Holcomb <damnbigman at gmail.com> wrote:

> On Tue, Jul 29, 2008 at 4:37 AM, Alex Fenton <alex at pressure.to> wrote:
>
>> Hi Glen
>>
>> Glen Holcomb wrote:
>>
>>> In my application I have a few Grid objects in a Notebook.  The Grid
>>> objects are populated via GridTableBase.  Certain Grid cells need to have a
>>> choice interface (I'm artificially enforcing foreign key constraints).  All
>>> this works to the point where you try to edit the value for that cell.  The
>>> choice box renders (i.e. the drop down arrow appears) then the application
>>> segfaults.  Unfortunately I'm stuck developing this in a Windows (XP)
>>> environment so I can't do much with the segfault.  Any help would be most
>>> appreciated.
>>>
>> The problem here is the combination of GridTableBase and cell editors /
>> renderers, which makes the memory management very tricky. It's noted as a
>> bug here:
>>
>> http://rubyforge.org/tracker/index.php?func=detail&aid=19187&group_id=35&atid=218
>>
>> I don't know how to fix it in the library, but you should be able to work
>> around it by storing the cell editor in an instance variable somewhere. Then
>> ruby will mark it and preserve it from GC. From the code you posted on c.l.r
>> (please do post code on this mailing list as well)
>>
>> def get_attr(row, col, attr_kind)
>>  attr = Wx::GridCellAttr.new
>>
>>  if @db_table == "computers" and col == 4
>>   ## INSTEAD OF THIS
>>   # attr.set_editor(Wx::GridCellChoiceEditor.new(["CAD", "GIS", "CMT"]))
>>   ## TRY THIS
>>   @editors ||= []
>>   @editors << Wx::GridCellChoiceEditor.new(["CAD", "GIS", "CMT"])
>>   attr.set_editor(@editors.last)
>>  end
>>
>>  attr
>> end
>>
>> hth
>> alex
>>
>>
>>
>>
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>> wxruby-users at rubyforge.org
>> http://rubyforge.org/mailman/listinfo/wxruby-users
>>
>
> Thanks Alex, I'll give that a shot and let you know how it turns out.
>
> --
> "Hey brother Christian with your high and mighty errand, Your actions speak
> so loud, I can't hear a word you're saying."
>
> -Greg Graffin (Bad Religion)
>

Okay back sooner than I thought, turns out I had the code here at home after
all.  Still no go.  I tried GC.disable at the top of the app too and I get
the same exact behavior.

The dropdown menu renders for a split second then it reverts to looking like
the default cell.  After that any attempt to interact with the app causes
the segfault.

Oddly it doesn't segfault immediately and will infact continue to run until
I click anywhere in the window.  Returning focus to the app doesn't kill it
either.

-- 
"Hey brother Christian with your high and mighty errand, Your actions speak
so loud, I can't hear a word you're saying."

-Greg Graffin (Bad Religion)
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