Compiler: NonReactive annotation

[srubin]

Summary

How did you test this change?

[josephsavona]

This isn’t something we plan to support, at least not in the way it’s used in the fixtures. This NonReactive annotation appears intended to let you drop reactivity, like many frameworks notion of “untracked”, which our experience suggests is a footgun.

[srubin]

Thanks for the response, and understood! Creating this PR was an accident; It's not something I intended to submit upstream -- it's just something I am experimenting with. Our codebase heavily uses a custom hook based on the useEvent idea, so I'm exploring how React Compiler can simplify some of our use case.

[josephsavona]

Check out https://react.dev/reference/react/useEffectEvent

[srubin]

I'm aware of that, but my understanding is that it won't work for our use cases. It is only intended to be used within useEffects and doesn't guarantee a stable function reference. So, it won't help with avoiding re-renders of child components, e.g., those caused by passing event handler props to child components or other functions to be used within event handlers of child components.

Do not [...] pass them to other components or Hooks

and

Effect Event functions do not have a stable identity. Their identity intentionally changes on every render.

I'm not familiar with the history of what changed between that original RFC and shipping of the more limited approach in React 19.2. Our codebase has seen a lot of great performance improvements from our implementation of useEvent.