Calling Gc.compact() in cppia collects the current CppiaClosure/ScriptCallable?

[kevinresol]

I am not even sure if the title correctly describes the issue. But it seems to be the case for what I am seeing.

Looking at the stack trace below it seems like the function variable magically becomes null, while it was still usable 2 lines above (function->runFunctionClosure(ctx);)

What I notice is that there is a cpp.vm.Gc.compact() call inside the cppia function. Removing such call seems to fix the problem.

The setup is a bit complex to be isolated. So for now I am going to first describe the setup with text and see if there any insights and I hope it is some obvious gc usage issue. The following logic all happens in the same non-haxe thread:

1. Haxe is used as a library in a c++ project and it is initialized with:

   hxcpp_set_top_of_stack();
   const char *err = hxRunLibrary();
   

2. cppia bytecode is loaded and stored in a Haxe static variable

   module = cpp.cppia.Module.fromData(bytes);
   module.boot();
   

3. a class defined in cppia is initialized (Type.createInstance(module.resolveClass(name))) and a instance method is invoked via Reflect.callMethod
4. in such instance method cpp.vm.Gc.compact() is called
5. the crash in the screenshot happens, after the cppia method returns

Info:
macos: 15 (arm64)
haxe: 4.3.6
hxcpp: git (9687509)

[kevinresol]

In nightly haxe/hxcpp I actually get a Critical Error: Bad Allocation while collecting - from finalizer? when I run Gc.compact(). So this makes me curious: what is the correct usage of Gc.compact() within cppia?