React 19: DragDropProvider manager is destroyed during Strict Mode replay

[mnlttt]

Description

In React 19 development with StrictMode enabled, DragDropProvider can retain a manager instance after that instance has been destroyed during React’s development-only Effect replay.

useStableInstance creates the manager once and stores it in a ref, but its cleanup currently destroys ref.current from useInsertionEffect. The replayed lifecycle can therefore leave the mounted provider holding a destroyed manager.

Reproduction

1. Use React 19 in development mode with StrictMode enabled.
2. Render a DragDropProvider containing a draggable element.
3. Interact with the draggable element after the initial mount.

<StrictMode>
  <DragDropProvider>
    <Draggable />
  </DragDropProvider>
</StrictMode>

Expected behavior

The manager should remain usable for as long as its DragDropProvider remains mounted.

Actual behavior

The provider can retain a manager that has already been destroyed, so later drag interactions may fail.

Proposed direction

Move manager disposal out of useInsertionEffect and defer cleanup enough to distinguish the development-only Strict Mode replay from a real unmount.

I have a focused patch with a Storybook regression story and Playwright coverage ready to link in a pull request.

[clauderic]

Thanks for the precise diagnosis — we read packages/react/src/core/context/DragDropProvider.tsx and can confirm the root cause you describe:

function useStableInstance<T extends {destroy(): void}>(create: () => T): T {
  const ref = useRef<T | null>(null);

  if (!ref.current) {
    ref.current = create();
  }

  useInsertionEffect(() => {
    return () => ref.current?.destroy();
  }, []);

  return ref.current;
}

ref.current is only ever populated during render. Strict Mode's development-only effect replay runs the insertion-effect cleanup — which calls destroy() on the instance — and then re-runs setup without a re-render, so nothing recreates the manager. The provider stays mounted holding a destroyed DragDropManager.

Labelled as a bug against @dnd-kit/react. We see you've opened #2117 with a fix, a Storybook regression story and Playwright coverage — thank you, that's exactly the right shape. Leaving both for the maintainer to review together.