[test] Add a failing test for cycle serialization in segment prefetches

Requires a fix in React to pass (possibly facebook/react#35471).

closes #86401

Author: unstubbable

test/e2e/app-dir/segment-cache/basic/app/cycle/client.tsx

@@ -0,0 +1,9 @@
+'use client'
+
+export function ClientComponent({ testProp }: { testProp: { self: unknown } }) {
+  return (
+    <div id="cycle-check">
+      {testProp.self === testProp ? 'Cycle resolved' : 'Cycle broken'}
+    </div>
+  )
+}

test/e2e/app-dir/segment-cache/basic/app/cycle/page.tsx

@@ -0,0 +1,8 @@
+import { ClientComponent } from './client'
+
+export default async function Page() {
+  const cycle = { self: null as unknown }
+  cycle.self = cycle
+
+  return <ClientComponent testProp={cycle} />
+}

test/e2e/app-dir/segment-cache/basic/app/page.tsx

@@ -1,5 +1,14 @@
 import { LinkAccordion } from '../components/link-accordion'
 
 export default function Page() {
-  return <LinkAccordion href="/test">Go to test page</LinkAccordion>
+  return (
+    <>
+      <p>
+        <LinkAccordion href="/test">Go to test page</LinkAccordion>
+      </p>
+      <p>
+        <LinkAccordion href="/cycle">Go to cycle page</LinkAccordion>
+      </p>
+    </>
+  )
 }

test/e2e/app-dir/segment-cache/basic/segment-cache-basic.test.ts

@@ -412,4 +412,43 @@ describe('segment cache (basic tests)', () => {
     const content = await page.textContent()
     expect(content).toContain('Cache Life Seconds Page')
   })
+
+  // TODO: Requires a fix in React.
+  it.failing(
+    'can handle circular references in client component props',
+    async () => {
+      let act: ReturnType<typeof createRouterAct>
+      const browser = await next.browser('/', {
+        beforePageLoad(page) {
+          act = createRouterAct(page)
+        },
+      })
+
+      // Reveal the link to trigger a prefetch.
+      const link = await act(
+        async () => {
+          await browser
+            .elementByCss('input[data-link-accordion="/cycle"]')
+            .click()
+          return browser.elementByCss('a[href="/cycle"]')
+        },
+        { includes: 'testProp' }
+      )
+
+      await act(
+        async () => {
+          await link.click()
+
+          // The page should render immediately because it was prefetched, and it
+          // should show the resolved cycle text.
+          expect(await browser.elementById('cycle-check').text()).toBe(
+            'Cycle resolved'
+          )
+        },
+        // No additional requests were required, because everything was
+        // prefetched.
+        'no-requests'
+      )
+    }
+  )
 })