fix(desktop): hide Windows subprocess consoles (#802)

Ensure Electron sidecar launch and Windows taskkill calls hide console windows, and pass the same hidden-window spawn option through desktop CLI and scheduled-task subprocess launches.

Tested: cd desktop && bun test ./electron/services/sidecarManager.test.ts
Tested: bun test src/server/__tests__/conversation-service.test.ts src/server/__tests__/cron-scheduler-launcher.test.ts
Tested: bun run check:native
Tested: bun run check:server
Not-tested: Windows GUI quit smoke
Confidence: medium
Scope-risk: narrow

desktop/electron/services/sidecarManager.test.ts

@@ -12,6 +12,7 @@ import {
   proxyUrlFromElectronProxyRules,
   pushStartupLog,
   resolveHostTriple,
+  spawnSidecar,
   windowsPowerShellOverride,
   type SidecarChild,
 } from './sidecarManager'
@@ -145,7 +146,7 @@ describe('Electron sidecar manager', () => {
     const spawnAsync = vi.fn()
     const spawnSyncFn = vi.fn()
     killSidecar(child, false, { platform: 'win32', spawnAsync: spawnAsync as never, spawnSyncFn: spawnSyncFn as never })
-    expect(spawnAsync).toHaveBeenCalledWith('taskkill', ['/F', '/T', '/PID', '777'], { stdio: 'ignore' })
+    expect(spawnAsync).toHaveBeenCalledWith('taskkill', ['/F', '/T', '/PID', '777'], { stdio: 'ignore', windowsHide: true })
     expect(spawnSyncFn).not.toHaveBeenCalled()
     expect(child.kill).not.toHaveBeenCalled()
   })
@@ -155,10 +156,29 @@ describe('Electron sidecar manager', () => {
     const spawnAsync = vi.fn()
     const spawnSyncFn = vi.fn()
     killSidecar(child, true, { platform: 'win32', spawnAsync: spawnAsync as never, spawnSyncFn: spawnSyncFn as never })
-    expect(spawnSyncFn).toHaveBeenCalledWith('taskkill', ['/F', '/T', '/PID', '777'], { stdio: 'ignore' })
+    expect(spawnSyncFn).toHaveBeenCalledWith('taskkill', ['/F', '/T', '/PID', '777'], { stdio: 'ignore', windowsHide: true })
     expect(spawnAsync).not.toHaveBeenCalled()
   })
 
+  it('hides Windows console windows when launching sidecars', () => {
+    const spawned = {} as SidecarChild
+    const spawnFn = vi.fn(() => spawned)
+    const existsSyncFn = vi.fn(() => true)
+    const plan = {
+      command: '/app/desktop/src-tauri/binaries/claude-sidecar-x86_64-pc-windows-msvc.exe',
+      args: ['server', '--port', '49321'],
+      env: { CLAUDE_H5_AUTO_PUBLIC_URL: '1' },
+    }
+
+    expect(spawnSidecar(plan, { existsSyncFn, spawnFn: spawnFn as never })).toBe(spawned)
+    expect(existsSyncFn).toHaveBeenCalledWith(plan.command)
+    expect(spawnFn).toHaveBeenCalledWith(plan.command, plan.args, {
+      env: plan.env,
+      stdio: ['ignore', 'pipe', 'pipe'],
+      windowsHide: true,
+    })
+  })
+
   it('forwards a PowerShell shell choice to the sidecar only on Windows', () => {
     expect(windowsPowerShellOverride('pwsh.exe', 'win32')).toBe('pwsh.exe')
     expect(windowsPowerShellOverride('powershell.exe', 'win32')).toBe('powershell.exe')

desktop/electron/services/sidecarManager.ts

@@ -16,6 +16,11 @@ export type SidecarPlan = {
   env: NodeJS.ProcessEnv
 }
 
+export type SpawnSidecarDeps = {
+  existsSyncFn?: typeof existsSync
+  spawnFn?: typeof spawn
+}
+
 const PROXY_ENV_KEYS = [
   'HTTP_PROXY',
   'HTTPS_PROXY',
@@ -225,13 +230,15 @@ export function createAdapterPlan({
   }
 }
 
-export function spawnSidecar(plan: SidecarPlan): SidecarChild {
-  if (!existsSync(plan.command)) {
+export function spawnSidecar(plan: SidecarPlan, deps: SpawnSidecarDeps = {}): SidecarChild {
+  const exists = deps.existsSyncFn ?? existsSync
+  if (!exists(plan.command)) {
     throw new Error(`Electron sidecar binary not found: ${plan.command}. Run "cd desktop && bun run build:sidecars" first.`)
   }
-  return spawn(plan.command, plan.args, {
+  return (deps.spawnFn ?? spawn)(plan.command, plan.args, {
     env: plan.env,
     stdio: ['ignore', 'pipe', 'pipe'],
+    windowsHide: true,
   })
 }
 
@@ -251,8 +258,9 @@ export function killSidecar(child: SidecarChild, sync = false, deps: KillSidecar
   const platform = deps.platform ?? process.platform
   if (platform === 'win32' && child.pid) {
     const args = ['/F', '/T', '/PID', String(child.pid)]
-    if (sync) (deps.spawnSyncFn ?? spawnSync)('taskkill', args, { stdio: 'ignore' })
-    else (deps.spawnAsync ?? spawn)('taskkill', args, { stdio: 'ignore' })
+    const options = { stdio: 'ignore', windowsHide: true } as const
+    if (sync) (deps.spawnSyncFn ?? spawnSync)('taskkill', args, options)
+    else (deps.spawnAsync ?? spawn)('taskkill', args, options)
     return
   }
   child.kill()

src/server/__tests__/conversation-service.test.ts

@@ -3,6 +3,7 @@ import * as fs from 'node:fs/promises'
 import * as os from 'node:os'
 import * as path from 'node:path'
 import {
+  buildConversationCliSpawnOptions,
   ConversationService,
   DESKTOP_CLI_GRACEFUL_SHUTDOWN_TIMEOUT_MS,
 } from '../services/conversationService.js'
@@ -181,6 +182,19 @@ describe('ConversationService', () => {
     await expect(fs.stat(path.dirname(env.CLAUDE_CODE_DIAGNOSTICS_FILE))).resolves.toBeTruthy()
   })
 
+  test('builds hidden CLI spawn options for desktop session subprocesses', () => {
+    const env = { CLAUDECODE: '1' }
+
+    expect(buildConversationCliSpawnOptions('/workspace/project', env)).toEqual({
+      cwd: '/workspace/project',
+      env,
+      stdin: 'pipe',
+      stdout: 'pipe',
+      stderr: 'pipe',
+      windowsHide: true,
+    })
+  })
+
   test('buildChildEnv pins desktop memory to the current sanitized project directory', async () => {
     const service = new ConversationService() as any
     const workDir = path.join(tmpDir, 'workspace', 'myself_code', 'claude-code-haha')

src/server/__tests__/cron-scheduler-launcher.test.ts

@@ -5,6 +5,7 @@ import * as path from 'path'
 
 import {
   buildCronCliArgs,
+  buildCronTaskSpawnOptions,
   CronScheduler,
   resolveCronProjectRoot,
 } from '../services/cronScheduler.js'
@@ -146,6 +147,19 @@ describe('cron scheduler launcher resolution', () => {
     ])
   })
 
+  it('builds hidden CLI spawn options for scheduled task subprocesses', () => {
+    const env = { CLAUDECODE: '1' }
+
+    expect(buildCronTaskSpawnOptions('/workspace/project', env)).toEqual({
+      stdin: 'pipe',
+      stdout: 'pipe',
+      stderr: 'pipe',
+      cwd: '/workspace/project',
+      env,
+      windowsHide: true,
+    })
+  })
+
   it('prefers an explicit CC_HAHA_ROOT when it points at a source checkout', async () => {
     const sourceRoot = path.join(tmpDir, 'source')
     await createSourceRoot(sourceRoot)

src/server/services/conversationService.ts

@@ -62,6 +62,20 @@ export function cliExitSeverity(code: number | null): 'info' | 'error' {
   return 'error'
 }
 
+export function buildConversationCliSpawnOptions(
+  cwd: string,
+  env: NodeJS.ProcessEnv,
+) {
+  return {
+    cwd,
+    env,
+    stdin: 'pipe',
+    stdout: 'pipe',
+    stderr: 'pipe',
+    windowsHide: true,
+  } as const
+}
+
 type AttachmentRef = {
   type: 'file' | 'image'
   name?: string
@@ -285,13 +299,7 @@ export class ConversationService {
 
     let proc: ReturnType<typeof Bun.spawn>
     try {
-      proc = Bun.spawn(args, {
-        cwd: launchWorkDir,
-        env: childEnv,
-        stdin: 'pipe',
-        stdout: 'pipe',
-        stderr: 'pipe',
-      })
+      proc = Bun.spawn(args, buildConversationCliSpawnOptions(launchWorkDir, childEnv))
     } catch (spawnErr) {
       void diagnosticsService.recordEvent({
         type: 'cli_spawn_failed',

src/server/services/cronScheduler.ts

@@ -41,6 +41,20 @@ export type TaskRun = {
   sessionId?: string // links to a session for rich output rendering
 }
 
+export function buildCronTaskSpawnOptions(
+  cwd: string,
+  env: NodeJS.ProcessEnv,
+) {
+  return {
+    stdin: 'pipe',
+    stdout: 'pipe',
+    stderr: 'pipe',
+    cwd,
+    env,
+    windowsHide: true,
+  } as const
+}
+
 // ─── Output extraction ────────────────────────────────────────────────────────
 
 /**
@@ -518,13 +532,7 @@ export class CronScheduler {
     const childEnv = await this.buildTaskChildEnv(workDir, task)
     const proc = Bun.spawn(
       cliArgs,
-      {
-        stdin: 'pipe',
-        stdout: 'pipe',
-        stderr: 'pipe',
-        cwd: workDir,
-        env: childEnv,
-      },
+      buildCronTaskSpawnOptions(workDir, childEnv),
     )
 
     this.runningTasks.set(task.id, { proc, startedAt: Date.now(), runId })