Function tree

common/script/json_api.cpp:48–51

struct JSON* is opaque to scripts, so the only thing checkable at the boundary is that a pointer was passed at all — a NULL one used to fault inside nlohmann, several frames from the call that got it wrong.

    // boundary is that a pointer was passed at all — a NULL one used to fault
    // inside nlohmann, several frames from the call that got it wrong.
    nlohmann::json* tree(const ScriptArgs& args, int i)
    {
        return (nlohmann::json*)args.ptr(i);
    }

    // The heap's destroy function for a tree: json_new's `new`, undone.
    void deleteJson(void* ptr)