fix(desktop): stop status-stack remounts from re-arming a dead-runtime poll storm (#98434)

apps/desktop/src/app/chat/composer/status-stack/index.tsx

@@ -21,7 +21,6 @@ import {
   dismissBackgroundProcess,
   groupStatusItems,
   refreshBackgroundProcesses,
-  resetBackgroundPollingGuard,
   type StatusGroup,
   stopBackgroundProcess
 } from '@/store/composer-status'
@@ -103,13 +102,15 @@ export function ComposerStatusStack({ queue, sessionId }: ComposerStatusStackPro
   const groups = useMemo(() => groupStatusItems(items), [items])
 
   // Seed from the registry on session open; event-driven refreshes (terminal /
-  // process tool completions) live in use-message-stream.
+  // process tool completions) live in use-message-stream. This must NOT reset
+  // the gone-polling latch: a mount/remount is not proof of a fresh runtime
+  // binding (a boot-restored tile can remount repeatedly while still bound to
+  // a dead runtime id), so clearing it here re-arms an endless 4001 storm
+  // against that id. The latch is reset at the actual rebind seams instead —
+  // gateway reconnect and runtime re-mint (see resetBackgroundPollingGuard
+  // call sites in use-gateway-boot.ts and store/gateway.ts).
   useEffect(() => {
     if (sessionId) {
-      // Opening/rebinding a session is a fresh runtime binding: clear any
-      // gone-latch left by a previous runtime under this id so the poll below
-      // is allowed to run again (see resetBackgroundPollingGuard).
-      resetBackgroundPollingGuard(sessionId)
       void refreshBackgroundProcesses(sessionId)
       void refreshSessionGoal(sessionId)
     }

apps/desktop/src/app/chat/composer/status-stack/polling-guard.test.tsx

@@ -0,0 +1,78 @@
+import { cleanup, render } from '@testing-library/react'
+import { MemoryRouter } from 'react-router'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { I18nProvider } from '@/i18n'
+import { resetBackgroundPollingGuard } from '@/store/composer-status'
+import { $gateway } from '@/store/gateway'
+
+import { ComposerStatusStack } from './index'
+
+// The stack measures itself into a surface var — jsdom has no ResizeObserver.
+class ResizeObserverStub {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+}
+
+vi.stubGlobal('ResizeObserver', ResizeObserverStub)
+
+const SID = 'sess-dead-runtime'
+
+function renderStack() {
+  return render(
+    <MemoryRouter>
+      <I18nProvider configClient={null} initialLocale="en">
+        <ComposerStatusStack queue={null} sessionId={SID} />
+      </I18nProvider>
+    </MemoryRouter>
+  )
+}
+
+// #98434: a boot-restored tile can stay bound to a dead runtime id and remount
+// repeatedly (no genuine rebind ever happens). The mount effect used to clear
+// the gone-polling latch on every mount, so each remount re-armed the 4001
+// storm against that id forever.
+describe('ComposerStatusStack dead-runtime remount', () => {
+  beforeEach(() => {
+    resetBackgroundPollingGuard()
+  })
+
+  afterEach(() => {
+    cleanup()
+    $gateway.set(null as never)
+    resetBackgroundPollingGuard()
+  })
+
+  it('does not re-poll process.list after a remount once the session is latched gone', async () => {
+    const request = vi.fn(async (method: string) => {
+      if (method === 'process.list') {
+        throw new Error('session not found')
+      }
+
+      return {}
+    })
+
+    const processListCalls = () => request.mock.calls.filter(([method]) => method === 'process.list').length
+
+    $gateway.set({ request } as never)
+
+    const first = renderStack()
+    await Promise.resolve()
+    await Promise.resolve()
+
+    expect(processListCalls()).toBe(1)
+
+    first.unmount()
+
+    const second = renderStack()
+    await Promise.resolve()
+    await Promise.resolve()
+
+    // Before the fix: the mount effect cleared the latch, so this remount
+    // re-fired process.list against the same dead id.
+    expect(processListCalls()).toBe(1)
+
+    second.unmount()
+  })
+})