Re: lv2 support for Debian 12 & zooming crash

Ted Felix <ted-Ll1PANez7xxWk0Htik3J/[email protected]> Wed, 21 Jan 2026 14:12:53 -0500
Newsgroups gmane.comp.audio.rosegarden.user
Message-ID <[email protected]>
 > If this is a bug and very rare, will it be named after me?

   Ha!  No.  It will be named after whatever part of Qt is messing this up.

   Give the latest in git a try.  I've rewritten all the matrix zoom 
code and it might be more stable for you now.

Ted.

On 1/21/26 6:52 AM, Babarosa wrote:
> Do you have a procedure that starts from an empty composition?
> 
> Not really, I didn't manage to crash Rosegarden using an empty composition.
> 
> Please do not laugh, but to trigger this crash I use the zoom wheels very rapidly like a lunatic (!) from maximum to minimum. Sometimes Rosegarden crashes after 15 movements, sometimes it takes 30 seconds.
> 
> If this is a bug and very rare, will it be named after me?
> 
> Thanks and Greetings, Michael
> 
> 
>> Gesendet: Montag, 19. Januar 2026 um 03:25
>> Von: "Ted Felix" <ted-Ll1PANez7xxWk0Htik3J/[email protected]>
>> An: Babarosa <[email protected]>, rosegarden-user <rosegarden-user-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
>> Betreff: Re: [Rosegarden-user] lv2 support for Debian 12 & zooming crash
>>
>> Fascinating.  This crash only touches us once at Panned.cpp:66.  And
>> that's just a message forward.  Unlikely that it is an rg problem.  More
>> likely a Qt5 bug.  We might want to try watching for a null event
>> pointer there, but I have a feeling that never happens as it would cause
>> an earlier crash (shorter call stack).
>>
>>     Do you have a procedure that starts from an empty composition?  Don't
>> spend any time on it if not.  It would just be nice to see if it is
>> reproducible with Qt6 and Philip could test that very easily.
>>
>>     I'll spend a little time beating it up with some huge compositions I
>> have lying around.
>>
>> Ted.
>>
>> On 1/18/26 5:24 PM, Babarosa wrote:
>> &gt; Please find attached the info. I can reproduce this crash.
>> &gt;
>> &gt; Thank you for helping, Michael
>> &gt;
>> &gt; Am 18.01.26 um 16:43 schrieb Ted Felix:
>> &gt;&gt; Ok. Usually for this kind of thing, running a debug build using ASAN
>> &gt;&gt; will give us a lot more information when it does crash.&nbsp; Or you can
>> &gt;&gt; run a debug build with gdb, which is a little more cumbersome, but
>> &gt;&gt; should get some good crash information for us to work with.
>> &gt;&gt;
>> &gt;&gt; &nbsp; Let me know if you need help setting either of those up.&nbsp; The cmake
>> &gt;&gt; line for ASAN is:
>> &gt;&gt;
>> &gt;&gt; cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS="-Werror -
>> &gt;&gt; fsanitize=address -fno-omit-frame-pointer"
>> &gt;&gt;
>> &gt;&gt; &nbsp; It's in the README.md.
>> &gt;&gt;
>> &gt;&gt; Ted.