Regression (runtime-v0.1.107): eager per-file ScriptingVM in File::import breaks deferred view-model binding

[bassrock]

Summary

Since runtime-v0.1.107, a script in a state machine that reads data-bound view-model properties throws attempt to index nil (and its effects never apply) when the host binds the view-model instance after loading the file via the CommandQueue. It worked on runtime-v0.1.106 and earlier.

Bisect

Built rive_render (headless CommandQueue host) against successive tags:

runtime	result
v0.1.106	✅ script runs, reads bound VM data correctly
v0.1.107	❌ attempt to index nil on data-bound property access in the script
v0.1.127	❌ same

Cause

src/command_server.cpp, CommandServer::processCommands() loadFile case, gained (v0.1.107):

#ifdef WITH_RIVE_SCRIPTING
    auto scriptingContext = std::make_unique<CPPRuntimeScriptingContext>(m_factory);
    scriptingContext->setRenderContext(m_factory);
    auto vm = make_rcp<ScriptingVM>(std::move(scriptingContext));
    rcp<rive::File> file = rive::File::import(rivBytes, m_factory, nullptr, m_fileAssetLoader, vm.get());
#else
    rcp<rive::File> file = rive::File::import(rivBytes, m_factory, nullptr, m_fileAssetLoader);
#endif

The per-file ScriptingVM is now created eagerly, inside File::import, so the file's script instances initialize during import. But a CommandQueue host typically binds view-model data after loadFile:

loadFile → instantiateArtboard/StateMachine → createDefaultInstance →
setViewModelInstance* → bindViewModelInstance → advance

So the script's first run happens against a view model that isn't bound yet. Reads of data-bound (incl. nested) properties resolve to nil. Even though the script re-runs when the VM is later bound, the data-bound targets it needs are unavailable at the point it errors.

Expected

A script should be able to observe view-model data that the host binds after a scripted import (the pre-v0.1.107 behavior), or there should be a documented way to defer/re-initialize the script VM after bindViewModelInstance.

Workaround

Importing without the eager VM (the pre-0.1.107 File::import(...) path) restores correct behavior — scripts then initialize lazily, after the view model is bound.

Environment

• Headless CommandQueue/CommandServer host (Metal on macOS, Vulkan/SwiftShader on Linux), WITH_RIVE_SCRIPTING enabled.
• Reproduces identically on macOS and Linux; not platform-specific.