(fix) Handle the stale ref for fwd (#2075)

compat/src/index.js

@@ -417,9 +417,9 @@ function memo(c, comparer) {
  */
 function forwardRef(fn) {
 	function Forwarded(props) {
-		let ref = props.ref;
-		delete props.ref;
-		return fn(props, ref);
+		let clone = assign({}, props);
+		delete clone.ref;
+		return fn(clone, props.ref);
 	}
 	Forwarded.prototype.isReactComponent = true;
 	Forwarded._forwarded = true;

compat/test/browser/forwardRef.test.js

@@ -6,10 +6,11 @@ import {
 	hydrate,
 	memo,
 	useState,
+	useRef,
 	useImperativeHandle
 } from '../../src';
 import { setupScratch, teardown } from '../../../test/_util/helpers';
-import { setupRerender } from 'preact/test-utils';
+import { setupRerender, act } from 'preact/test-utils';
 /* eslint-disable react/jsx-boolean-value, react/display-name, prefer-arrow-callback */
 
 /** @jsx h */
@@ -351,4 +352,33 @@ describe('forwardRef', () => {
 		expect(spy).to.be.calledOnce;
 		expect(spy).to.be.calledWithExactly({ foo: 100 });
 	});
+
+	it('stale ref missing with passed useRef', () => {
+		let _ref = null;
+		let _set = null;
+		const Inner = forwardRef((props, ref) => {
+			const [_, setState] = useState(null);
+			_ref = ref;
+			_set = setState;
+			return <div ref={ref} />;
+		});
+
+		const Parent = () => {
+			const parentRef = useRef(null);
+			return <Inner ref={parentRef}>child</Inner>;
+		};
+
+		act(() => {
+			render(<Parent />, scratch);
+		});
+
+		expect(_ref).not.to.be.undefined;
+
+		act(() => {
+			_set(1);
+			rerender();
+		});
+
+		expect(_ref).not.to.be.undefined;
+	});
 });