Crash creating Script FX in SlotFX — null pointer in JavascriptMasterEffect::applyEffect

[tahinar]

HISE 4.1.0, macOS 26.5.2 (Tahoe), Apple Silicon (Mac17,2), standalone app.

Crash occurs when adding a Script FX module to a SlotFX effect slot. Reproduced
twice — first attempt with audio actively playing on the channel, second attempt
on a muted channel with no kit loaded (to rule out a race condition), same crash
both times.

EXC_BAD_ACCESS (SIGSEGV), KERN_INVALID_ADDRESS at 0x0000000000001000.

Crashing thread (Thread 9, com.apple.audio.IOThread.client):

hise::JavascriptMasterEffect::applyEffect(juce::AudioBuffer&, int, int)
hise::MasterEffectProcessor::renderWholeBuffer(juce::AudioBuffer&)
hise::EffectProcessorChain::renderMasterEffects(juce::AudioBuffer&)
hise::ModulatorSynth::renderNextBlockWithModulators(...)
hise::ModulatorSampler::renderNextBlockWithModulators(...)
hise::ModulatorSynthChain::renderNextBlockWithModulators(...) [x2, nested chains]
hise::MainController::processBlockCommon(...)
hise::BackendProcessor::processBlock(...)

far: 0x0000000000001000 — reads as a near-null pointer dereference inside
applyEffect(), suggesting the DSP network reference isn't valid at the point the
audio thread tries to render through it.

A second thread (Thread 0, JUCE Message Thread) was concurrently mid-construction
of the ScriptNode editor panel when the crash was captured:

scriptnode::DspNetworkGraph::DspNetworkGraph(scriptnode::DspNetwork*)
hise::HiseShapeButton::HiseShapeButton(...)
non-virtual thunk to scriptnode::DspNetworkGraph::RootUndoButtons::createPath(...)
juce::Path::loadPathFromData(...)
juce::MemoryInputStream::read(...)

Not certain if these two are related or coincidental, including both since they
were captured in the same crash report.

Steps to reproduce:

1. Fresh HISE 4.1.0 standalone project (also happens in [your project name])
2. Add a SlotFX effect slot to a channel
3. Set its effect type to Script FX via the Module Tree
4. Crash occurs [immediately / when opening its DSP network editor — confirm which]

Happy to attach the full crash log (I have it) and/or a minimal repro project if
useful.

[David Healey]

@tahinar Try with the latest version of HISE, 4.1.0 is ancient.