Fix hang

Author: Sg312

apps/sim/app/api/copilot/chat/queries.ts

@@ -11,7 +11,7 @@ import {
   createInternalServerErrorResponse,
   createUnauthorizedResponse,
 } from '@/lib/copilot/request/http'
-import { readFilePreviewSessions } from '@/lib/copilot/request/session'
+import { deriveReplayTerminalState, readFilePreviewSessions } from '@/lib/copilot/request/session'
 import { readEvents } from '@/lib/copilot/request/session/buffer'
 import { toStreamBatchEvent } from '@/lib/copilot/request/session/types'
 import { authorizeWorkflowByWorkspacePermission } from '@/lib/workflows/utils'
@@ -71,6 +71,7 @@ export async function GET(req: NextRequest) {
         events: ReturnType<typeof toStreamBatchEvent>[]
         previewSessions: Awaited<ReturnType<typeof readFilePreviewSessions>>
         status: string
+        error?: string
       } | null = null
       if (chat.conversationId) {
         try {
@@ -94,15 +95,21 @@ export async function GET(req: NextRequest) {
             }),
           ])
 
+          const replayState = deriveReplayTerminalState(events)
+          const snapshotError =
+            replayState.error ?? (typeof run?.error === 'string' ? run.error : undefined)
           streamSnapshot = {
             events: events.map(toStreamBatchEvent),
             previewSessions,
             status:
-              typeof run?.status === 'string'
-                ? run.status
-                : events.length > 0
-                  ? 'active'
-                  : 'unknown',
+              typeof replayState.status === 'string'
+                ? replayState.status
+                : typeof run?.status === 'string'
+                  ? run.status
+                  : events.length > 0
+                    ? 'active'
+                    : 'unknown',
+            ...(typeof snapshotError === 'string' ? { error: snapshotError } : {}),
           }
         } catch (error) {
           logger.warn('Failed to load copilot chat stream snapshot', {

apps/sim/app/api/copilot/chat/stream/route.test.ts

@@ -3,7 +3,7 @@
  */
 
 import { NextRequest } from 'next/server'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import {
   MothershipStreamV1CompletionStatus,
   MothershipStreamV1EventType,
@@ -31,6 +31,7 @@ vi.mock('@/lib/copilot/request/session', () => ({
   readEvents,
   readFilePreviewSessions,
   checkForReplayGap,
+  deriveReplayTerminalState: vi.fn(() => ({})),
   createEvent: (event: Record<string, unknown>) => ({
     stream: {
       streamId: event.streamId,
@@ -81,6 +82,10 @@ describe('copilot chat stream replay route', () => {
     checkForReplayGap.mockResolvedValue(null)
   })
 
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
   it('returns preview sessions in batch mode', async () => {
     getLatestRunForStream.mockResolvedValue({
       status: 'active',
@@ -121,6 +126,28 @@ describe('copilot chat stream replay route', () => {
     })
   })
 
+  it('returns the persisted run error in batch mode for terminal errors', async () => {
+    getLatestRunForStream.mockResolvedValue({
+      status: 'error',
+      executionId: 'exec-1',
+      id: 'run-1',
+      error: 'tool replay failed',
+    })
+
+    const response = await GET(
+      new NextRequest(
+        'http://localhost:3000/api/copilot/chat/stream?streamId=stream-1&after=0&batch=true'
+      )
+    )
+
+    expect(response.status).toBe(200)
+    await expect(response.json()).resolves.toMatchObject({
+      success: true,
+      status: 'error',
+      error: 'tool replay failed',
+    })
+  })
+
   it('stops replay polling when run becomes cancelled', async () => {
     getLatestRunForStream
       .mockResolvedValueOnce({
@@ -148,6 +175,35 @@ describe('copilot chat stream replay route', () => {
     expect(getLatestRunForStream).toHaveBeenCalledTimes(2)
   })
 
+  it('stops replay once persisted terminal events are flushed even if the run row is still active', async () => {
+    getLatestRunForStream.mockResolvedValue({
+      status: 'active',
+      executionId: 'exec-1',
+      id: 'run-1',
+    })
+    readEvents.mockResolvedValue([
+      {
+        v: 1,
+        type: MothershipStreamV1EventType.complete,
+        seq: 1,
+        ts: '2026-01-01T00:00:00.000Z',
+        stream: { streamId: 'stream-1', cursor: '1' },
+        trace: { requestId: 'req-1' },
+        payload: {
+          status: MothershipStreamV1CompletionStatus.complete,
+        },
+      },
+    ])
+
+    const response = await GET(
+      new NextRequest('http://localhost:3000/api/copilot/chat/stream?streamId=stream-1&after=0')
+    )
+
+    const chunks = await readAllChunks(response)
+    expect(chunks.join('')).toContain(`"type":"${MothershipStreamV1EventType.complete}"`)
+    expect(getLatestRunForStream).toHaveBeenCalledTimes(1)
+  })
+
   it('emits structured terminal replay error when run metadata disappears', async () => {
     getLatestRunForStream
       .mockResolvedValueOnce({
@@ -167,4 +223,47 @@ describe('copilot chat stream replay route', () => {
     expect(body).toContain('"code":"resume_run_unavailable"')
     expect(body).toContain(`"type":"${MothershipStreamV1EventType.complete}"`)
   })
+
+  it('returns structured JSON when the initial replay lookup times out', async () => {
+    vi.useFakeTimers()
+    getLatestRunForStream.mockImplementation(() => new Promise(() => {}))
+
+    const responsePromise = GET(
+      new NextRequest('http://localhost:3000/api/copilot/chat/stream?streamId=stream-1&after=0')
+    )
+
+    await vi.advanceTimersByTimeAsync(10_000)
+
+    const response = await responsePromise
+    expect(response.status).toBe(504)
+    await expect(response.json()).resolves.toMatchObject({
+      error: 'The stream recovery timed out before replay could start.',
+      code: 'resume_initial_lookup_timeout',
+    })
+  })
+
+  it('returns structured JSON when batch replay times out', async () => {
+    vi.useFakeTimers()
+    getLatestRunForStream.mockResolvedValue({
+      status: 'active',
+      executionId: 'exec-1',
+      id: 'run-1',
+    })
+    readEvents.mockImplementation(() => new Promise(() => {}))
+
+    const responsePromise = GET(
+      new NextRequest(
+        'http://localhost:3000/api/copilot/chat/stream?streamId=stream-1&after=0&batch=true'
+      )
+    )
+
+    await vi.advanceTimersByTimeAsync(10_000)
+
+    const response = await responsePromise
+    expect(response.status).toBe(504)
+    await expect(response.json()).resolves.toMatchObject({
+      error: 'The stream batch replay timed out before completion.',
+      code: 'resume_batch_timeout',
+    })
+  })
 })