PluginWindow error when setting AutomatableParameters

Tracktion Engine
1

Hi

I’m making a simple GUI for the built-in Tracktion effects in DAW, I’m building. I’m using the code from PluginWindow.h from the examples and made a class TracktionPluginEditor that simply makes a Slider for each AutomatableParameter.
I set the Slider.onValue lambda like this:

onValueChange = [&] { param.setParameter(this->getValue(), NotificationType::dontSendNotification);
};

Opening up a plugin window for, say the Tracktion reverb works fine. The parameters show and moving the slider changes the plugin and the sound reacts accordingly. But if I close the plugin window and open up a new one, moving a slider now crashes the program. I get a
JUCE Message Thread (1): EXC_BAD_ACCESS (code=1, address=0x10)
It seems that there’s a bad Listener object being called in the lambda in juce_ValueTree.cpp :

void sendPropertyChangeMessage (const Identifier& property, ValueTree::Listener* listenerToExclude = nullptr)
{
ValueTree tree (*this);
callListenersForAllParents (listenerToExclude, [&] (Listener& l) {
l.valueTreePropertyChanged (tree, property);
});
}

but I can’t figure out why or what the originating object could be. I’ve tried to narrow the suspects down, tracing the calls and it looks like it’s a listener on the Plugin’s listener list.
Each Sliders is registered as a Listener on the AutomatableParameter, but I’m removing it again in the destructor, so I don’t think that’s the issue.

Does anyone have an idea of what might be going wrong?
Any suggestions appreciated!
I’m working on the Master branch btw.

2

Are you adding a listener somewhere but not removing it?

The easiest way of detecting these kinds of errors is using ASan (Address Sanitiser).

3

Yes! Found it. PluginWindow added as listener to the plugin’s valuetree, but forgot to remove.
Great tool. I didn’t know that. Thanks!