fix(nextjs): Fix infinite redirect loop when page does not exist (#5073)

.changeset/twenty-doors-glow.md

@@ -0,0 +1,5 @@
+---
+'@clerk/nextjs': patch
+---
+
+Bug fix: On keyless avoid infinite redirect loop when page does not exist and application is attempting to sync state with middleware.

integration/tests/next-quickstart-keyless.test.ts

@@ -37,6 +37,25 @@ test.describe('Keyless mode @quickstart', () => {
     await app.teardown();
   });
 
+  test('Navigates to non existed page (/_not-found) without a infinite redirect loop.', async ({ page, context }) => {
+    const u = createTestUtils({ app, page, context });
+    await u.page.goToAppHome();
+    await u.page.waitForClerkJsLoaded();
+    await u.po.expect.toBeSignedOut();
+
+    await u.po.keylessPopover.waitForMounted();
+
+    const redirectMap = new Map<string, number>();
+    page.on('request', request => {
+      const url = request.url();
+      redirectMap.set(url, (redirectMap.get(url) || 0) + 1);
+      expect(redirectMap.get(url)).toBeLessThanOrEqual(1);
+    });
+
+    await u.page.goToRelative('/something');
+    await u.page.waitForAppUrl('/something');
+  });
+
   test('Toggle collapse popover and claim.', async ({ page, context }) => {
     const u = createTestUtils({ app, page, context });
     await u.page.goToAppHome();

packages/nextjs/src/app-router/client/keyless-cookie-sync.tsx

@@ -1,14 +1,18 @@
 'use client';
 
 import type { AccountlessApplication } from '@clerk/backend';
+import { useSelectedLayoutSegments } from 'next/navigation';
 import type { PropsWithChildren } from 'react';
 import { useEffect } from 'react';
 
 import { canUseKeyless } from '../../utils/feature-flags';
 
 export function KeylessCookieSync(props: PropsWithChildren<AccountlessApplication>) {
+  const segments = useSelectedLayoutSegments();
+  const isNotFoundRoute = segments[0]?.startsWith('/_not-found') || false;
+
   useEffect(() => {
-    if (canUseKeyless) {
+    if (canUseKeyless && !isNotFoundRoute) {
       void import('../keyless-actions.js').then(m =>
         m.syncKeylessConfigAction({
           ...props,
@@ -17,7 +21,7 @@ export function KeylessCookieSync(props: PropsWithChildren<AccountlessApplicatio
         }),
       );
     }
-  }, []);
+  }, [isNotFoundRoute]);
 
   return props.children;
 }

packages/nextjs/src/app-router/client/keyless-creator-reader.tsx

@@ -1,16 +1,22 @@
+import { useSelectedLayoutSegments } from 'next/navigation';
 import React, { useEffect } from 'react';
 
 import type { NextClerkProviderProps } from '../../types';
 import { createOrReadKeylessAction } from '../keyless-actions';
 
 export const KeylessCreatorOrReader = (props: NextClerkProviderProps) => {
   const { children } = props;
+  const segments = useSelectedLayoutSegments();
+  const isNotFoundRoute = segments[0]?.startsWith('/_not-found') || false;
   const [state, fetchKeys] = React.useActionState(createOrReadKeylessAction, null);
   useEffect(() => {
+    if (isNotFoundRoute) {
+      return;
+    }
     React.startTransition(() => {
       fetchKeys();
     });
-  }, []);
+  }, [isNotFoundRoute]);
 
   if (!React.isValidElement(children)) {
     return children;

packages/nextjs/src/app-router/keyless-actions.ts

@@ -5,19 +5,28 @@ import { redirect, RedirectType } from 'next/navigation';
 
 import { errorThrower } from '../server/errorThrower';
 import { detectClerkMiddleware } from '../server/headers-utils';
-import { getKeylessCookieName } from '../server/keyless';
+import { getKeylessCookieName, getKeylessCookieValue } from '../server/keyless';
 import { canUseKeyless } from '../utils/feature-flags';
 
 export async function syncKeylessConfigAction(args: AccountlessApplication & { returnUrl: string }): Promise<void> {
   const { claimUrl, publishableKey, secretKey, returnUrl } = args;
   const cookieStore = await cookies();
+  const request = new Request('https://placeholder.com', { headers: await headers() });
+
+  const keyless = getKeylessCookieValue(name => cookieStore.get(name)?.value);
+  const pksMatch = keyless?.publishableKey === publishableKey;
+  const sksMatch = keyless?.secretKey === secretKey;
+  if (pksMatch && sksMatch) {
+    // Return early, syncing in not needed.
+    return;
+  }
+
+  // Set the new keys in the cookie.
   cookieStore.set(getKeylessCookieName(), JSON.stringify({ claimUrl, publishableKey, secretKey }), {
     secure: true,
     httpOnly: true,
   });
 
-  const request = new Request('https://placeholder.com', { headers: await headers() });
-
   // We cannot import `NextRequest` due to a bundling issue with server actions in Next.js 13.
   // @ts-expect-error Request will work as well
   if (detectClerkMiddleware(request)) {