npm i
npm run dev
react-refresh leaks FiberRootNodes from secondary renderers.
When R3F's Canvas unmounts, react-refresh's onCommitFiberRoot sees a late commit (didError=true, !wasMounted && !isMounted) and adds the root to failedRoots / helpersByRoot — never cleaned up.
Click the button, then observe all 16 values stay "alive" in dev mode.
In a production build (no react-refresh) they are properly GC'd.
After pressing "Collect garbage" button in Devtools:
In production build (note the last value is still retained, but that is a separate issue in R3F that I have investigated and reported):
