Crash in AUv2 Wrapper using VST3 SDK v3.7.7


We recently updated to the VST3 SDK v3.7.7 and now users are reporting a weird issue. It’s related to the implementation and its recent ObjcClassBuilder style refactoring.

Namely in lines 191/192: If AUView::setFrame() is called when the GUI is opened everything works fine. However, once the user resizes our GUI which invokes CFrame::setFrame(), inst.callSuper<void (NSRect)> gets dispached to [self setFrame...] instead of the super class’ method, which, of course, yields an endless recursion / stack overflow → crash.

The only difference I can see on the call stack for things to go wrong is that AUView::setFrame() is called from the VST3 library which calls into the AUWrapper lib.

To make things even stranger this only happens on Intel or in some circumstances on arm64. You can for instance reproduce the issue in the latest GarageBand on Ventura 13.1, but it’ll only happen there when GB is run in Rosetta mode.

I can work around this by either including a recurse guard or by commenting out the call to the super class’ setFrame function which, of course, isn’t the way to go because the container window won’t get resized that way.

It seems to me that something is wrong with the objcclassbuilder.h implementation. We didn’t change anything in the client code so I’m pretty sure it does have to do with the aforementioned refactoring of I still can’t figure out what’s the reasoning behind the change to a “dynamic” ObjCClassBuilder based implementation here at all.

EDIT: Please check the latet commit in GitHub - raygit83/vst3_public_sdk: VST 3 Implementation Helper Classes And Examples . It looks like when reverting back to a vanilla Objective C implementation the issue won’t occur at all.


Hi Ray,
I currently try to reproduce this, but no luck so far. Can you reproduce the issue with the AGain example from the SDK?

Hi Arne,

Not yet, but I’ll try ASAP or come up with a minimal example that demonstrates this behavior. The plugin has to call CFrame::setZoom() after the editor has been opened.

Please note that it only seems to occur in some circumstances: It has been observed in REAPER (both platforms) or GarageBand and Logic running on Intel or in Rosetta2 mode. There it strangely enough doesn’t happen on arm64.