test(desktop): cover submit drift through e2e

apps/desktop/e2e/fixtures.ts

@@ -318,6 +318,7 @@ export async function launchDesktop(
 export interface MockBackendFixture {
   app: ElectronApplication
   page: Page
+  mock: Awaited<ReturnType<typeof startMockServer>>
   mockUrl: string
   sandbox: Sandbox
   cleanup: () => Promise<void>
@@ -346,6 +347,7 @@ export async function setupMockBackend(): Promise<MockBackendFixture> {
   return {
     app,
     page,
+    mock,
     mockUrl: mock.url,
     sandbox,
     cleanup: async () => {

apps/desktop/e2e/mock-server.ts

@@ -22,10 +22,16 @@ const CANNED_REPLY = 'Hello from the mock inference server! The full boot chain
 /**
  * Start the mock server on an ephemeral port.
  *
- * @returns a handle with `port`, `url`, and `close()`.
+ * @returns a handle with `port`, `url`, received user prompts, and `close()`.
  */
-export function startMockServer(): Promise<{ port: number; url: string; close: () => Promise<void> }> {
+export function startMockServer(): Promise<{
+  port: number
+  url: string
+  receivedPrompts: string[]
+  close: () => Promise<void>
+}> {
   return new Promise((resolve, reject) => {
+    const receivedPrompts: string[] = []
     const server = http.createServer((req, res) => {
       // CORS headers — the Electron renderer doesn't need them, but they
       // don't hurt and make the server usable from a browser context too.
@@ -75,6 +81,14 @@ export function startMockServer(): Promise<{ port: number; url: string; close: (
             // malformed JSON — treat as non-streaming with defaults
           }
 
+          const lastUserMessage = [...(parsed.messages ?? [])]
+            .reverse()
+            .find((message: { role?: unknown }) => message?.role === 'user')
+
+          if (typeof lastUserMessage?.content === 'string') {
+            receivedPrompts.push(lastUserMessage.content)
+          }
+
           const stream = parsed.stream === true
           const model = parsed.model || 'mock-model'
 
@@ -187,6 +201,7 @@ export function startMockServer(): Promise<{ port: number; url: string; close: (
       resolve({
         port,
         url,
+        receivedPrompts,
         close: () =>
           new Promise((resolveClose, rejectClose) => {
             server.close((err) => {

apps/desktop/e2e/submit-drift.spec.ts

@@ -0,0 +1,75 @@
+/**
+ * Regression coverage for #69578: harmless route-token churn during a send
+ * must not make the desktop silently drop the prompt before prompt.submit.
+ */
+
+import { test, expect } from './test'
+
+import {
+  type MockBackendFixture,
+  setupMockBackend,
+  waitForAppReady,
+} from './fixtures'
+
+const PROMPT = 'E2E route token drift must still submit this prompt.'
+
+let fixture: MockBackendFixture | null = null
+
+test.beforeAll(async () => {
+  fixture = await setupMockBackend()
+  await waitForAppReady(fixture!, 120_000)
+})
+
+test.afterAll(async () => {
+  await fixture?.cleanup()
+  fixture = null
+})
+
+test('submits while same-chat search tokens churn during new-session creation', async ({}, testInfo) => {
+  const { page, mock } = fixture!
+  const composer = page.locator('[contenteditable="true"]').first()
+
+  await composer.click()
+  await composer.type(PROMPT, { delay: 10 })
+
+  // The submit pipeline snapshots the route synchronously, then awaits session
+  // creation. Keep changing only the query string of whichever chat route is
+  // current. Before #69578, comparing the raw route token treated this as a
+  // user chat switch and aborted before prompt.submit.
+  await page.evaluate(() => {
+    let revision = 0
+    const interval = window.setInterval(() => {
+      const pathname = window.location.hash.slice(1).split(/[?#]/, 1)[0] || '/new'
+      window.location.hash = `${pathname}?e2e-route-churn=${revision++}`
+    }, 1)
+
+    ;(window as typeof window & { __e2eStopRouteChurn?: () => void }).__e2eStopRouteChurn = () => {
+      window.clearInterval(interval)
+    }
+  })
+
+  try {
+    await page.keyboard.press('Enter')
+
+    await expect
+      .poll(() => mock.receivedPrompts.includes(PROMPT), { timeout: 60_000 })
+      .toBe(true)
+
+    await page.waitForFunction(
+      prompt => document.querySelector('[data-slot="aui_thread-viewport"]')?.textContent?.includes(prompt) ?? false,
+      PROMPT,
+      { timeout: 15_000 },
+    )
+    await page.waitForFunction(
+      () => document.querySelector('[data-slot="aui_thread-viewport"]')?.textContent?.includes('mock inference server') ?? false,
+      undefined,
+      { timeout: 60_000 },
+    )
+  } finally {
+    await page.evaluate(() => {
+      ;(window as typeof window & { __e2eStopRouteChurn?: () => void }).__e2eStopRouteChurn?.()
+    })
+  }
+
+  await page.screenshot({ path: testInfo.outputPath('same-chat-route-churn-submitted.png') })
+})