fix(ui): Stop the sign-in start card flashing after a code is accepted

.changeset/olive-donuts-wave.md

@@ -0,0 +1,5 @@
+---
+'@clerk/ui': patch
+---
+
+Fix the sign-in start card briefly flashing over `<SignIn />` after a verification code is accepted, before the app renders its signed-in state.

packages/ui/src/components/SignIn/SignInFactorOne.tsx

@@ -123,8 +123,17 @@ function SignInFactorOneInternal(): JSX.Element {
 
   const [passwordErrorCode, setPasswordErrorCode] = React.useState<PasswordErrorCode | null>(null);
 
+  const setActiveTookOverRef = React.useRef(false);
+
   React.useEffect(() => {
     if (__internal_setActiveInProgress) {
+      // setActive owns navigation from here on. It consumes the sign-in (status -> null), so the
+      // check below would fire as setActive winds down and flash the start card over a success.
+      setActiveTookOverRef.current = true;
+      return;
+    }
+
+    if (setActiveTookOverRef.current) {
       return;
     }
 

packages/ui/src/components/SignIn/SignInFactorTwo.tsx

@@ -29,8 +29,17 @@ function SignInFactorTwoInternal(): JSX.Element {
     toggleAllStrategies,
   } = useSecondFactorSelection(signIn.supportedSecondFactors);
 
+  const setActiveTookOverRef = React.useRef(false);
+
   React.useEffect(() => {
     if (clerk.__internal_setActiveInProgress) {
+      // setActive owns navigation from here on. It consumes the sign-in (status -> null), so the
+      // check below would fire as setActive winds down and redirect over a flow that succeeded.
+      setActiveTookOverRef.current = true;
+      return;
+    }
+
+    if (setActiveTookOverRef.current) {
       return;
     }
 

packages/ui/src/components/SignIn/__tests__/SignInFactorOneSetActiveGuard.test.tsx

@@ -0,0 +1,118 @@
+import { ClerkAPIResponseError } from '@clerk/shared/error';
+import type { SignInResource } from '@clerk/shared/types';
+import { waitFor } from '@testing-library/react';
+import { describe, expect, it } from 'vitest';
+
+import { bindCreateFixtures } from '@/test/create-fixtures';
+import { render, screen } from '@/test/utils';
+
+import { SignInFactorOne } from '../SignInFactorOne';
+
+const { createFixtures } = bindCreateFixtures('SignIn');
+
+/**
+ * Mirrors the real `setActive` lifecycle: the flag goes up, the completed sign-in is consumed on
+ * the client (`status` -> `null`), the card re-renders while the flag is still up (clerk-js emits
+ * transitive state right before navigating), then the flag drops once navigation is done.
+ */
+const mockSetActiveLifecycle = (fixtures: any) => {
+  let release = () => {};
+  const gate = new Promise<void>(resolve => (release = resolve));
+
+  fixtures.clerk.setActive.mockImplementation(async (params: any) => {
+    fixtures.clerk.__internal_setActiveInProgress = true;
+    fixtures.signIn.status = null;
+    await gate;
+    await params.navigate?.({ session: { currentTask: null }, decorateUrl: (url: string) => url });
+    fixtures.clerk.__internal_setActiveInProgress = false;
+  });
+
+  return { finishSetActive: () => release() };
+};
+
+describe('SignIn setActive guard', () => {
+  it('does not bounce factor one back to the start card once setActive has completed', async () => {
+    const { wrapper, fixtures } = await createFixtures(f => {
+      f.withEmailAddress();
+      f.withPreferredSignInStrategy({ strategy: 'otp' });
+      f.startSignInWithEmailAddress({ supportEmailCode: true, supportPassword: false });
+    });
+
+    fixtures.signIn.prepareFirstFactor.mockReturnValueOnce(Promise.resolve({} as SignInResource));
+    fixtures.signIn.attemptFirstFactor.mockResolvedValueOnce({
+      status: 'complete',
+      createdSessionId: 'sess_123',
+    } as any);
+    const { finishSetActive } = mockSetActiveLifecycle(fixtures);
+
+    const { userEvent, rerender } = render(<SignInFactorOne />, { wrapper });
+
+    await userEvent.type(screen.getByLabelText(/Enter verification code/i), '123456');
+    await waitFor(() => expect(fixtures.clerk.setActive).toHaveBeenCalled(), { timeout: 3000 });
+
+    rerender(<SignInFactorOne />);
+    finishSetActive();
+    await waitFor(() => expect((fixtures.clerk as any).__internal_setActiveInProgress).toBe(false));
+
+    // The host app keeps <SignIn> mounted until its own signed-in state propagates, so the card
+    // re-renders at least once more after setActive resolves.
+    rerender(<SignInFactorOne />);
+
+    await waitFor(() => expect(fixtures.clerk.setActive).toHaveBeenCalled());
+    expect(fixtures.router.navigate).not.toHaveBeenCalledWith('../');
+  });
+
+  it('does not bounce back to the start card after a signUpIfMissing transfer completes', async () => {
+    const { wrapper, fixtures, props } = await createFixtures(f => {
+      f.withEmailAddress();
+      f.withPreferredSignInStrategy({ strategy: 'otp' });
+      f.withEnumerationProtection();
+      f.startSignInWithEmailAddress({ supportEmailCode: true, supportPassword: false });
+    });
+    props.setProps({ withSignUp: true });
+
+    fixtures.signIn.prepareFirstFactor.mockReturnValueOnce(Promise.resolve({} as SignInResource));
+    fixtures.signIn.attemptFirstFactor.mockImplementationOnce(() => {
+      (fixtures.signIn as any).firstFactorVerification = { status: 'transferable' };
+      return Promise.reject(
+        new ClerkAPIResponseError('Error', {
+          data: [{ code: 'sign_up_if_missing_transfer', long_message: '', message: '' }],
+          status: 404,
+        }),
+      );
+    });
+    // A sign-up with no additional requirements transfers straight to `complete`.
+    fixtures.signUp.create.mockResolvedValueOnce({ status: 'complete', createdSessionId: 'sess_123' } as any);
+    const { finishSetActive } = mockSetActiveLifecycle(fixtures);
+
+    const { userEvent, rerender } = render(<SignInFactorOne />, { wrapper });
+
+    await userEvent.type(screen.getByLabelText(/Enter verification code/i), '123456');
+    await waitFor(() => expect(fixtures.clerk.setActive).toHaveBeenCalled(), { timeout: 3000 });
+
+    rerender(<SignInFactorOne />);
+    finishSetActive();
+    await waitFor(() => expect((fixtures.clerk as any).__internal_setActiveInProgress).toBe(false));
+
+    // The terminal redirect leaves the page, but the document stays alive while the browser
+    // fetches the next one, so the card can still re-render and bounce.
+    rerender(<SignInFactorOne />);
+
+    expect(fixtures.router.navigate).not.toHaveBeenCalledWith('../');
+  });
+
+  it('still bounces to the start card when the sign-in was abandoned without setActive', async () => {
+    const { wrapper, fixtures } = await createFixtures(f => {
+      f.withEmailAddress();
+      f.withPreferredSignInStrategy({ strategy: 'otp' });
+      f.startSignInWithEmailAddress({ supportEmailCode: true, supportPassword: false });
+    });
+
+    fixtures.signIn.prepareFirstFactor.mockReturnValueOnce(Promise.resolve({} as SignInResource));
+    (fixtures.signIn as any).status = 'needs_identifier';
+
+    render(<SignInFactorOne />, { wrapper });
+
+    await waitFor(() => expect(fixtures.router.navigate).toHaveBeenCalledWith('../'));
+  });
+});