fix(ui): Extract ref from ExternalElementMounter props to prevent nodeRef overwrite (React 19) (#8534)

Author: wobsoriano

.changeset/soft-worms-battle.md

@@ -0,0 +1,5 @@
+---
+"@clerk/ui": patch
+---
+
+Fixed custom page icons not rendering in React 19 due to a forwarded ref overwriting the internal node reference.

packages/ui/src/utils/ExternalElementMounter.tsx

@@ -1,11 +1,21 @@
+import type { Ref } from 'react';
 import { useEffect, useRef } from 'react';
 
 type ExternalElementMounterProps = {
   mount: (el: HTMLDivElement) => void;
   unmount: (el?: HTMLDivElement) => void;
+  // In React 19, ref is a regular prop for function components (not wrapped in
+  // forwardRef). Without this field, ref ends up in ...rest and overwrites the
+  // internal nodeRef when spread onto the div, preventing mount from being called.
+  ref?: Ref<HTMLDivElement>;
 };
 
-export const ExternalElementMounter = ({ mount, unmount, ...rest }: ExternalElementMounterProps) => {
+export const ExternalElementMounter = ({
+  mount,
+  unmount,
+  ref: _forwardedRef,
+  ...rest
+}: ExternalElementMounterProps) => {
   const nodeRef = useRef(null);
 
   useEffect(() => {

packages/ui/src/utils/__tests__/ExternalElementMounter.test.tsx

@@ -0,0 +1,62 @@
+import { render, waitFor } from '@testing-library/react';
+import React from 'react';
+import { describe, expect, it, vi } from 'vitest';
+
+import { ExternalElementMounter } from '../ExternalElementMounter';
+
+describe('ExternalElementMounter', () => {
+  it('calls mount with the host div element', async () => {
+    const mount = vi.fn();
+    const unmount = vi.fn();
+
+    render(
+      <ExternalElementMounter
+        mount={mount}
+        unmount={unmount}
+      />,
+    );
+
+    await waitFor(() => expect(mount).toHaveBeenCalledOnce());
+    expect(mount).toHaveBeenCalledWith(expect.any(HTMLDivElement));
+  });
+
+  it('calls unmount with the same element when removed', async () => {
+    const mount = vi.fn();
+    const unmount = vi.fn();
+
+    const { unmount: removeComponent } = render(
+      <ExternalElementMounter
+        mount={mount}
+        unmount={unmount}
+      />,
+    );
+
+    await waitFor(() => expect(mount).toHaveBeenCalledOnce());
+    const mountedEl = mount.mock.calls[0][0];
+    removeComponent();
+
+    expect(unmount).toHaveBeenCalledWith(mountedEl);
+  });
+
+  it('calls mount even when a forwarded ref is present in props (React 19 regression)', async () => {
+    // In React 19, ref is a regular prop. Before the fix, a ref forwarded through
+    // the component chain would land in ...rest and overwrite nodeRef in
+    // `<div ref={nodeRef} {...rest} />`, preventing mount from being called.
+    // React 18 strips ref before passing to non-forwardRef components, so the
+    // regression is only observable in a React 19 runtime — but this test guards
+    // against it being reintroduced.
+    const mount = vi.fn();
+    const unmount = vi.fn();
+
+    render(
+      React.createElement(ExternalElementMounter, {
+        mount,
+        unmount,
+        ref: { current: null },
+      }),
+    );
+
+    await waitFor(() => expect(mount).toHaveBeenCalledOnce());
+    expect(mount).toHaveBeenCalledWith(expect.any(HTMLDivElement));
+  });
+});