Breaking changes in React experimental branch

[jackpope]

React is preparing changes, including some breaking, for the next major release. There are changes to the Reconciler that break @react-three/fiber.

To repro:

• Install react and react-dom @experimental
• Load @react-three/fiber demo
• Observe error

sandbox: https://codesandbox.io/p/sandbox/react-three-fiber-experimental-9hqh35

To prepare for the new versions, @react-three/fiber should build against the latest changes by upgrading react-reconciler, which requires new methods since 0.27.0. See all

[CodyJasonBennett]

Thanks for looking out. We're aware of this and plan to upgrade our reconciler alongside React 19 with our v9 release. I can make a PR for this shortly.