useImperativeHandle callback never called (when rendering w/ enzyme)

Do you want to request a feature or report a bug? bug

What is the current behavior?

I have the code:

function Form(props, ref) {

  React.useImperativeHandle(ref, () => {
    debugger;
    return {
      setErrors: () => {},
    };
  });
}

export default React.forwardRef(Form);

When I use the component, the callback passed to useImperativeHandle is never called. (The debugger statement is never hit).

The code that I have using the component is:

import {mount} from 'enzyme';

describe('Form component', () => {
  test('exposes a ref', async () => {
    let formRef;
    mount(<Form ref={ref => (formRef = ref)}>{() => <span>test</span>}</Form>);
    await pause(500); // this is just a setTimeout to give time for the hooks to run.
    expect(formRef.setErrors).toBeDefined();
  });

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn’t have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:

https://codesandbox.io/s/v8rqy75mn5

What is the expected behavior?

Callback should be called and returned value should be used as the ref.

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

    "react": "16.8.0-alpha.1",
    "react-dom": "16.8.0-alpha.1",
    "enzyme": "3.8.0",
    "enzyme-adapter-react-16": "1.8.0",

[gaearon]

You want:

const Form = React.forwardRef((props, ref) => {
  React.useImperativeHandle(ref, () => {
    debugger;
    return {
      setErrors: () => {},
    };
  });
})

Don’t miss React.forwardRef.

In the future might make this unnecessary but we can’t yet because that would have been a breaking change.

[threepointone]

Followed the chain and it looks like workarounds/fix existed on the enzyme side, and it’s not to do with React. Closing this issue.