fix: make Device Hub simulator launch opt-in

src/__tests__/client.test.ts

@@ -67,13 +67,13 @@ test('apps.open resolves session device identifiers from open response', async (
     app: 'Settings',
     platform: 'ios',
     relaunch: true,
-    noDeviceHub: true,
+    deviceHub: true,
   });
 
   assert.equal(setup.calls.length, 1);
   assert.equal(setup.calls[0]?.command, 'open');
   assert.deepEqual(setup.calls[0]?.positionals, ['Settings']);
-  assert.equal(setup.calls[0]?.flags?.noDeviceHub, true);
+  assert.equal(setup.calls[0]?.flags?.deviceHub, true);
   assert.equal(result.identifiers.session, 'qa');
   assert.equal(result.identifiers.deviceId, 'SIM-001');
   assert.equal(result.identifiers.udid, 'SIM-001');

src/client-normalizers.ts

@@ -282,7 +282,7 @@ export function buildFlags(options: InternalRequestOptions): CommandFlags {
     relaunch: options.relaunch,
     shutdown: options.shutdown,
     saveScript: options.saveScript,
-    noDeviceHub: options.noDeviceHub,
+    deviceHub: options.deviceHub,
     noRecord: options.noRecord,
     backMode: options.backMode,
     metroHost: options.metroHost,

src/client-types.ts

@@ -193,7 +193,7 @@ export type AppOpenOptions = AgentDeviceRequestOverrides &
     launchArgs?: string[];
     relaunch?: boolean;
     saveScript?: boolean | string;
-    noDeviceHub?: boolean;
+    deviceHub?: boolean;
     noRecord?: boolean;
     runtime?: SessionRuntimeHints;
   };
@@ -884,7 +884,7 @@ export type InternalRequestOptions = AgentDeviceClientConfig &
     relaunch?: boolean;
     shutdown?: boolean;
     saveScript?: boolean | string;
-    noDeviceHub?: boolean;
+    deviceHub?: boolean;
     noRecord?: boolean;
     backMode?: BackMode;
     metroHost?: string;

src/commands/cli-grammar/apps.ts

@@ -45,7 +45,7 @@ export const appCliReaders = {
     launchArgs: flags.launchArgs,
     relaunch: flags.relaunch,
     saveScript: flags.saveScript,
-    noDeviceHub: flags.noDeviceHub,
+    deviceHub: flags.deviceHub,
     noRecord: flags.noRecord,
   }),
   close: (positionals, flags) => ({

src/commands/client-command-metadata.ts

@@ -63,9 +63,7 @@ export const clientCommandMetadata = [
     ),
     relaunch: booleanField('Force relaunch.'),
     saveScript: jsonSchemaField<boolean | string>({ oneOf: [booleanSchema(), stringSchema()] }),
-    noDeviceHub: booleanField(
-      'Skip Xcode Device Hub and use the standalone Simulator app when surfacing Apple simulators.',
-    ),
+    deviceHub: booleanField('Use Xcode Device Hub when surfacing Apple simulators.'),
     noRecord: booleanField('Do not record this action.'),
   }),
   defineClientCommandMetadata('close', {

src/daemon-client.ts

@@ -53,7 +53,7 @@ export type OpenAppOptions = {
   launchArgs?: NonNullable<DaemonRequest['flags']>['launchArgs'];
   out?: NonNullable<DaemonRequest['flags']>['out'];
   saveScript?: NonNullable<DaemonRequest['flags']>['saveScript'];
-  noDeviceHub?: NonNullable<DaemonRequest['flags']>['noDeviceHub'];
+  deviceHub?: NonNullable<DaemonRequest['flags']>['deviceHub'];
   relaunch?: boolean;
   runtime?: DaemonRequest['runtime'];
   meta?: Omit<NonNullable<DaemonRequest['meta']>, 'uploadedArtifactId' | 'clientArtifactPaths'>;
@@ -226,7 +226,7 @@ export async function openApp(options: OpenAppOptions = {}): Promise<DaemonRespo
     launchArgs,
     out,
     saveScript,
-    noDeviceHub,
+    deviceHub,
     relaunch,
     runtime,
     meta,
@@ -249,7 +249,7 @@ export async function openApp(options: OpenAppOptions = {}): Promise<DaemonRespo
       ...(launchArgs !== undefined ? { launchArgs } : {}),
       ...(out !== undefined ? { out } : {}),
       ...(saveScript !== undefined ? { saveScript } : {}),
-      ...(noDeviceHub !== undefined ? { noDeviceHub } : {}),
+      ...(deviceHub !== undefined ? { deviceHub } : {}),
       ...(relaunch ? { relaunch: true } : {}),
     },
     ...(runtime !== undefined ? { runtime } : {}),

src/daemon/__tests__/device-ready.test.ts

@@ -55,21 +55,21 @@ test('ensureDeviceReady caches successful simulator readiness checks', async ()
 
   expect(mockEnsureBootedSimulator).toHaveBeenCalledTimes(1);
   expect(mockEnsureBootedSimulator).toHaveBeenCalledWith(device, {
+    deviceHub: undefined,
     focusExisting: undefined,
-    preferStandalone: undefined,
   });
 });
 
 test('ensureDeviceReady focuses cached simulator readiness checks when requested', async () => {
   const device: DeviceInfo = { ...IOS_SIMULATOR, simulatorSetPath: '/tmp/simset-a' };
 
   await ensureDeviceReady(device);
-  await ensureDeviceReady({ ...device }, { focusExisting: true, noDeviceHub: true });
+  await ensureDeviceReady({ ...device }, { deviceHub: true, focusExisting: true });
 
   expect(mockEnsureBootedSimulator).toHaveBeenCalledTimes(2);
   expect(mockEnsureBootedSimulator).toHaveBeenLastCalledWith(
     { ...device },
-    { focusExisting: true, preferStandalone: true },
+    { deviceHub: true, focusExisting: true },
   );
 });
 

src/daemon/device-ready.ts

@@ -15,8 +15,8 @@ export const DEVICE_READY_CACHE_TTL_MS = 5_000;
 const readyCache = new Map<string, number>();
 
 export type DeviceReadyOptions = {
+  deviceHub?: boolean;
   focusExisting?: boolean;
-  noDeviceHub?: boolean;
 };
 
 export async function ensureDeviceReady(
@@ -36,8 +36,8 @@ export async function ensureDeviceReady(
     if (device.kind === 'simulator') {
       const { ensureBootedSimulator } = await import('../platforms/ios/simulator.ts');
       await ensureBootedSimulator(device, {
+        deviceHub: options.deviceHub,
         focusExisting: options.focusExisting,
-        preferStandalone: options.noDeviceHub,
       });
       markDeviceReady(cacheKey);
       return;

src/daemon/handlers/session-open-prepare.ts

@@ -109,8 +109,8 @@ export async function prepareOpenCommandDetails(params: {
 }): Promise<PreparedOpenCommandDetailsResult> {
   const { req, sessionName, sessionStore, device, surface, openTarget, existingSession } = params;
   await ensureDeviceReady(device, {
+    deviceHub: req.flags?.deviceHub === true,
     focusExisting: true,
-    noDeviceHub: req.flags?.noDeviceHub === true,
   });
   const { appBundleId, appName } = await resolvePreparedOpenIdentity({
     device,

src/platforms/ios/__tests__/index.test.ts

@@ -118,6 +118,41 @@ const mockRetryWithPolicy = vi.mocked(retryWithPolicy);
 const mockRunIosRunnerCommand = vi.mocked(runIosRunnerCommand);
 const mockEnsureBootedSimulator = vi.mocked(ensureBootedSimulator);
 const mockOpenIosSimulatorApp = vi.mocked(openIosSimulatorApp);
+
+type MockRunCmdResult = Awaited<ReturnType<typeof runCmd>>;
+type MockRunCmdResponse = MockRunCmdResult | (() => MockRunCmdResult);
+
+const OK_RESULT: MockRunCmdResult = { exitCode: 0, stdout: '', stderr: '' };
+
+function mockRunCmdResponses(responses: Record<string, MockRunCmdResponse>): void {
+  mockRunCmd.mockImplementation(async (cmd, args) => {
+    const key = formatMockRunCmdCall(cmd, args);
+    const response = responses[key];
+    if (!response) throw new Error(`Unexpected command: ${key}`);
+    return typeof response === 'function' ? response() : response;
+  });
+}
+
+function formatMockRunCmdCall(cmd: string, args: string[]): string {
+  return `${cmd} ${args.join(' ')}`;
+}
+
+function simulatorListDevicesResult(state: string): MockRunCmdResult {
+  return {
+    exitCode: 0,
+    stdout: JSON.stringify({
+      devices: {
+        'com.apple.CoreSimulator.SimRuntime.iOS-18-6': [{ udid: 'sim-1', state }],
+      },
+    }),
+    stderr: '',
+  };
+}
+
+function simulatorStateSequence(...states: string[]): () => MockRunCmdResult {
+  let index = 0;
+  return () => simulatorListDevicesResult(states[index++] ?? states.at(-1) ?? 'Booted');
+}
 const mockPrepareStatusBarForScreenshot = vi.mocked(prepareStatusBarForScreenshot);
 
 beforeEach(() => {
@@ -410,57 +445,49 @@ test('openIosApp custom scheme deep links on iOS devices require app bundle cont
   );
 });
 
-test('ensureBootedSimulator opens Device Hub after cold boot when available', async () => {
-  let listCallCount = 0;
-  mockRunCmd.mockImplementation(async (cmd, args) => {
-    if (cmd === 'xcrun' && args.join(' ') === 'simctl list devices -j') {
-      listCallCount += 1;
-      const state = listCallCount === 1 ? 'Shutdown' : 'Booted';
-      return {
-        exitCode: 0,
-        stdout: JSON.stringify({
-          devices: {
-            'com.apple.CoreSimulator.SimRuntime.iOS-18-6': [{ udid: 'sim-1', state }],
-          },
-        }),
-        stderr: '',
-      };
-    }
-    if (cmd === 'xcrun' && args.join(' ') === 'simctl boot sim-1') {
-      return { exitCode: 0, stdout: '', stderr: '' };
-    }
-    if (cmd === 'xcrun' && args.join(' ') === 'simctl bootstatus sim-1 -b') {
-      return { exitCode: 0, stdout: '', stderr: '' };
-    }
-    if (cmd === 'open' && args.join(' ') === '-a Device Hub') {
-      return { exitCode: 0, stdout: '', stderr: '' };
-    }
-    throw new Error(`Unexpected command: ${cmd} ${args.join(' ')}`);
+test('ensureBootedSimulator opens Simulator after cold boot by default', async () => {
+  mockRunCmdResponses({
+    'xcrun simctl list devices -j': simulatorStateSequence('Shutdown', 'Booted'),
+    'xcrun simctl boot sim-1': OK_RESULT,
+    'xcrun simctl bootstatus sim-1 -b': OK_RESULT,
+    'open -a Simulator': OK_RESULT,
   });
 
   await ensureBootedSimulator(IOS_TEST_SIMULATOR, { focusExisting: true });
 
   assert.equal(
     mockRunCmd.mock.calls.some(
-      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-a Device Hub',
+      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-a Simulator',
     ),
     true,
   );
 });
 
-test('openIosSimulatorApp falls back to Simulator when Device Hub is unavailable', async () => {
-  mockRunCmd.mockImplementation(async (cmd, args) => {
-    if (cmd === 'open' && args.join(' ') === '-a Device Hub') {
-      return { exitCode: 1, stdout: '', stderr: 'Unable to find application named Device Hub' };
-    }
-    if (cmd === 'open' && args.join(' ') === '-a Simulator') {
-      return { exitCode: 0, stdout: '', stderr: '' };
-    }
-    throw new Error(`Unexpected command: ${cmd} ${args.join(' ')}`);
+test('openIosSimulatorApp opens Simulator by default', async () => {
+  mockRunCmdResponses({
+    'open -a Simulator': OK_RESULT,
   });
 
   await openIosSimulatorApp();
 
+  assert.deepEqual(
+    mockRunCmd.mock.calls.map(([cmd, args]) => [cmd, args.join(' ')]),
+    [['open', '-a Simulator']],
+  );
+});
+
+test('openIosSimulatorApp uses Device Hub when opted in and falls back to Simulator', async () => {
+  mockRunCmdResponses({
+    'open -a Device Hub': {
+      exitCode: 1,
+      stdout: '',
+      stderr: 'Unable to find application named Device Hub',
+    },
+    'open -a Simulator': OK_RESULT,
+  });
+
+  await openIosSimulatorApp({ deviceHub: true });
+
   assert.deepEqual(
     mockRunCmd.mock.calls.map(([cmd, args]) => [cmd, args.join(' ')]),
     [
@@ -470,71 +497,60 @@ test('openIosSimulatorApp falls back to Simulator when Device Hub is unavailable
   );
 });
 
-test('ensureBootedSimulator opens Device Hub when already booted and available', async () => {
-  mockRunCmd.mockImplementation(async (cmd, args) => {
-    if (cmd === 'xcrun' && args.join(' ') === 'simctl list devices -j') {
-      return {
-        exitCode: 0,
-        stdout: JSON.stringify({
-          devices: {
-            'com.apple.CoreSimulator.SimRuntime.iOS-18-6': [{ udid: 'sim-1', state: 'Booted' }],
-          },
-        }),
-        stderr: '',
-      };
-    }
-    if (cmd === 'open' && args.join(' ') === '-a Device Hub') {
-      return { exitCode: 0, stdout: '', stderr: '' };
-    }
-    throw new Error(`Unexpected command: ${cmd} ${args.join(' ')}`);
+test('ensureBootedSimulator opens Simulator when already booted by default', async () => {
+  mockRunCmdResponses({
+    'xcrun simctl list devices -j': simulatorListDevicesResult('Booted'),
+    'open -a Simulator': OK_RESULT,
   });
 
   await ensureBootedSimulator(IOS_TEST_SIMULATOR, { focusExisting: true });
 
+  assert.deepEqual(
+    mockRunCmd.mock.calls.map(([cmd, args]) => [cmd, args.join(' ')]),
+    [
+      ['xcrun', 'simctl list devices -j'],
+      ['open', '-a Simulator'],
+    ],
+  );
+});
+
+test('ensureBootedSimulator opens Device Hub without activation when already booted and opted in', async () => {
+  mockRunCmdResponses({
+    'xcrun simctl list devices -j': simulatorListDevicesResult('Booted'),
+    'open -g -a Device Hub': OK_RESULT,
+  });
+
+  await ensureBootedSimulator(IOS_TEST_SIMULATOR, { deviceHub: true, focusExisting: true });
+
   assert.equal(
     mockRunCmd.mock.calls.some(
-      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-a Device Hub',
+      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-g -a Device Hub',
     ),
     true,
   );
   assert.equal(
     mockRunCmd.mock.calls.some(
-      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-a Simulator',
+      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-g -a Simulator',
     ),
     false,
   );
 });
 
-test('ensureBootedSimulator honors standalone Simulator preference when already booted', async () => {
-  mockRunCmd.mockImplementation(async (cmd, args) => {
-    if (cmd === 'xcrun' && args.join(' ') === 'simctl list devices -j') {
-      return {
-        exitCode: 0,
-        stdout: JSON.stringify({
-          devices: {
-            'com.apple.CoreSimulator.SimRuntime.iOS-18-6': [{ udid: 'sim-1', state: 'Booted' }],
-          },
-        }),
-        stderr: '',
-      };
-    }
-    if (cmd === 'open' && args.join(' ') === '-a Simulator') {
-      return { exitCode: 0, stdout: '', stderr: '' };
-    }
-    throw new Error(`Unexpected command: ${cmd} ${args.join(' ')}`);
+test('ensureBootedSimulator foregrounds Device Hub after cold boot when opted in', async () => {
+  mockRunCmdResponses({
+    'xcrun simctl list devices -j': simulatorStateSequence('Shutdown', 'Booted'),
+    'xcrun simctl boot sim-1': OK_RESULT,
+    'xcrun simctl bootstatus sim-1 -b': OK_RESULT,
+    'open -a Device Hub': OK_RESULT,
   });
 
-  await ensureBootedSimulator(IOS_TEST_SIMULATOR, {
-    focusExisting: true,
-    preferStandalone: true,
-  });
+  await ensureBootedSimulator(IOS_TEST_SIMULATOR, { deviceHub: true, focusExisting: true });
 
-  assert.deepEqual(
-    mockRunCmd.mock.calls.map(([cmd, args]) => [cmd, args.join(' ')]),
-    [
-      ['xcrun', 'simctl list devices -j'],
-      ['open', '-a Simulator'],
-    ],
+  assert.equal(
+    mockRunCmd.mock.calls.some(
+      ([cmd, args]) => cmd === 'open' && args.join(' ') === '-a Device Hub',
+    ),
+    true,
   );
 });
 
@@ -987,7 +1003,11 @@ test('screenshotIos retries simulator capture timeouts and eventually succeeds',
     );
     assert.equal(
       logLines.filter(
-        (line) => line === '__OPEN__ -a Device Hub' || line === '__OPEN__ -a Simulator',
+        (line) =>
+          line === '__OPEN__ -a Device Hub' ||
+          line === '__OPEN__ -a Simulator' ||
+          line === '__OPEN__ -g -a Device Hub' ||
+          line === '__OPEN__ -g -a Simulator',
       ).length,
       0,
       'should not focus simulator host app while retrying screenshots',