fix(files): answer 499 instead of 500 when a client disconnects mid-serve

apps/sim/app/api/files/serve/[...path]/route.test.ts

@@ -34,6 +34,7 @@ import {
   workspaceFileManagerMock,
   workspaceFileManagerMockFns,
 } from '@sim/testing/mocks/workspace-file-manager.mock'
+import { NextRequest } from 'next/server'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import { MAX_BUFFERED_TRANSFER_BYTES } from '@/lib/uploads/shared/types'
 
@@ -325,6 +326,24 @@ describe('File Serve API Route', () => {
     expect(serveLogger.error).not.toHaveBeenCalled()
   })
 
+  it('answers 499 without an error log when the client disconnects mid-read', async () => {
+    const controller = new AbortController()
+    mockReadLocalFileWithinLimit.mockImplementation(async () => {
+      controller.abort()
+      throw new Error('Request aborted')
+    })
+
+    const response = await GET(
+      new NextRequest('http://localhost:3000/api/files/serve/workspace/ws/report.md', {
+        signal: controller.signal,
+      }),
+      createRouteContext({ path: ['workspace', 'ws', 'report.md'] })
+    )
+
+    expect(response.status).toBe(499)
+    expect(serveLogger.error).not.toHaveBeenCalled()
+  })
+
   describe('versioned cache lifetime', () => {
     const principal = createExecutorPrincipal({
       subjectUserId: 'test-user-id',

apps/sim/app/api/files/serve/[...path]/route.ts

@@ -389,6 +389,7 @@ export const GET = withRouteHandler(
         request.method === 'HEAD'
       )
     } catch (error) {
+      if (request.signal.aborted) throw error
       if (error instanceof InternalUnauthenticatedError) {
         logger.warn('Unauthorized file access attempt', { error: error.message })
         return NextResponse.json(
@@ -599,6 +600,7 @@ async function handleLocalFile(
       options.ifNoneMatch
     )
   } catch (error) {
+    if (signal?.aborted) throw error
     logServeFailure('Error reading local file:', error)
     throw error
   }
@@ -689,6 +691,7 @@ async function handleCloudProxy(
       options.ifNoneMatch
     )
   } catch (error) {
+    if (signal?.aborted) throw error
     logServeFailure('Error downloading from cloud storage:', error)
     throw error
   }