Remove warning for ref cleanup function (facebook#28883)

Resources - RFC: reactjs/rfcs#205 - Warning implemented in facebook#22313 - Warning enabled in facebook#23145 - Feature added in facebook#25686 We have warned to prevent the old behavior since 18.0.0. The new feature has been on in canary for a while but still triggering the warning. This PR cleans up the warning for 19

Author: jackpope

packages/react-dom/src/__tests__/refs-test.js

@@ -706,45 +706,4 @@ describe('refs return clean up function', () => {
  expect(setup).toHaveBeenCalledTimes(1);
  expect(cleanUp).toHaveBeenCalledTimes(1);
  });
-
- it('warns if clean up function is returned when called with null', async () => {
- const container = document.createElement('div');
- const cleanUp = jest.fn();
- const setup = jest.fn();
- let returnCleanUp = false;
-
- const root = ReactDOMClient.createRoot(container);
- await act(() => {
- root.render(
- <div
- ref={_ref => {
- setup(_ref);
- if (returnCleanUp) {
- return cleanUp;
- }
- }}
- />,
- );
- });
-
- expect(setup).toHaveBeenCalledTimes(1);
- expect(cleanUp).toHaveBeenCalledTimes(0);
-
- returnCleanUp = true;
-
- await expect(async () => {
- await act(() => {
- root.render(
- <div
- ref={_ref => {
- setup(_ref);
- if (returnCleanUp) {
- return cleanUp;
- }
- }}
- />,
- );
- });
- }).toErrorDev('Unexpected return value from a callback ref in div');
- });
 });

packages/react-reconciler/src/ReactFiberCommitWork.js

@@ -318,30 +318,20 @@ function safelyDetachRef(current: Fiber, nearestMountedAncestor: Fiber | null) {
  }
  }
  } else if (typeof ref === 'function') {
- let retVal;
  try {
  if (shouldProfile(current)) {
  try {
  startLayoutEffectTimer();
- retVal = ref(null);
+ ref(null);
  } finally {
  recordLayoutEffectDuration(current);
  }
  } else {
- retVal = ref(null);
+ ref(null);
  }
  } catch (error) {
  captureCommitPhaseError(current, nearestMountedAncestor, error);
  }
- if (__DEV__) {
- if (typeof retVal === 'function') {
- console.error(
- 'Unexpected return value from a callback ref in %s. ' +
- 'A callback ref should not return a function.',
- getComponentNameFromFiber(current),
- );
- }
- }
  } else {
  // $FlowFixMe[incompatible-use] unable to narrow type to RefObject
  ref.current = null;