# `react-doctor/no-async-event-handler-without-reentry-guard`

Async mutating handler without re-entry guard

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

## Validate the diagnostic

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

Confirm the reported code matches `react-doctor/no-async-event-handler-without-reentry-guard`. 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
function Save({ payload }) {
  const [, setSaved] = useState(false);
  const handleSave = useCallback(async () => {
    await api.post("/save", payload);
    setSaved(true);
  }, [payload]);
  return <button onClick={handleSave} />;
}
```

### Corrected pattern

```tsx
function Save({ payload }) {
  const [isSaving, setIsSaving] = useState(false);
  const [, setSaved] = useState(false);
  const handleSave = useCallback(async () => {
    if (isSaving) return;
    setIsSaving(true);
    try {
      await api.post("/save", payload);
      setSaved(true);
    } finally {
      setIsSaving(false);
    }
  }, [isSaving, payload]);
  return <button disabled={isSaving} onClick={handleSave} />;
}
```

## 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-async-event-handler-without-reentry-guard` diagnostic in the current repository.

Required change:
- Block re-entry before the first `await`. Return when `busy` is true, or set the flag before entering `try`. Reset it in `finally`, and disable the control while the request runs.

Reference transformation:

Before:
```tsx
function Save({ payload }) {
  const [, setSaved] = useState(false);
  const handleSave = useCallback(async () => {
    await api.post("/save", payload);
    setSaved(true);
  }, [payload]);
  return <button onClick={handleSave} />;
}
```

After:
```tsx
function Save({ payload }) {
  const [isSaving, setIsSaving] = useState(false);
  const [, setSaved] = useState(false);
  const handleSave = useCallback(async () => {
    if (isSaving) return;
    setIsSaving(true);
    try {
      await api.post("/save", payload);
      setSaved(true);
    } finally {
      setIsSaving(false);
    }
  }, [isSaving, payload]);
  return <button disabled={isSaving} onClick={handleSave} />;
}
```

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`.

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.
````