# `react-doctor/no-ref-callback-cleanup-before-react-19`

Ref cleanup requires React 19

- **Category:** Bugs
- **Severity:** warn
- **Source:** oxlint-plugin-react-doctor
- **Framework:** global
- **Enabled when:** react:18
- **Disabled when:** react:19

## Validate the diagnostic

Confirm the reported code matches this rule before you edit it.

Confirm the reported code matches `react-doctor/no-ref-callback-cleanup-before-react-19`. Compare it with the Before example and verify the same API, framework, and execution context. Treat it as a false positive only when one of those conditions differs.

## Compare the code

The corrected pattern shows a focused way to address the diagnostic.

### Reported pattern

```tsx
<Widget ref={(node) => { connect(node); return () => disconnect(node); }} />
```

### Corrected pattern

```tsx
const Panel = () => {
  const widgetRef = useRef(null);
  useEffect(() => {
    const node = widgetRef.current;
    connect(node);
    return () => disconnect(node);
  }, []);
  return <Widget ref={widgetRef} />;
};
```

## How to fix

Use the corrected pattern as a reference. Preserve behavior that the rule does not require you to change.

### Copyable fix prompt

Copy this self-contained prompt into your coding agent after you confirm the diagnostic.

````text
Fix every confirmed `react-doctor/no-ref-callback-cleanup-before-react-19` diagnostic in the current repository.

Required change:
- React 18 ignores functions returned from ref callbacks. Handle cleanup when React calls the ref with `null`, or require React 19 before returning a cleanup function.

Reference transformation:

Before:
```tsx
<Widget ref={(node) => { connect(node); return () => disconnect(node); }} />
```

After:
```tsx
const Panel = () => {
  const widgetRef = useRef(null);
  useEffect(() => {
    const node = widgetRef.current;
    connect(node);
    return () => disconnect(node);
  }, []);
  return <Widget ref={widgetRef} />;
};
```

Constraints:
- Confirm the reported code matches the Before pattern.
- Make the smallest change that fixes the root cause.
- Preserve behavior and interfaces unrelated to this diagnostic.
- Reuse existing project components, utilities, and conventions.
- Do not introduce render-phase side effects, render-phase state updates, or Hooks rule violations.
- Adapt identifiers and framework details instead of copying blindly.
- Do not disable the rule or suppress matching code.
- Confirm this rule is enabled for the project: `react:18`.
- Do not edit code when this condition applies: react:19.

Verification:
- Run focused tests for the changed behavior.
- Run React Doctor and confirm this diagnostic no longer appears.
- Report the files changed and any checks you could not run.
````