fix(app-management): surface app list failures instead of caching an empty list

src/tests/tools/app-management/resolve-app-id.test.ts

@@ -4,13 +4,15 @@ const rehydratedDriver = {rehydrated: true};
 
 const mockResolveDriver = jest.fn<(sessionId?: string) => Promise<any>>();
 const mockListAppsFromDevice = jest.fn<(...args: any[]) => Promise<{packageName: string; appName: string}[]>>();
+const mockGetPlatformName = jest.fn<() => string>();
+const mockIsXCUITestDriverSession = jest.fn<() => boolean>();
 
 jest.unstable_mockModule('../../../session-store', () => ({
   // The in-memory cache is empty after an MCP process recycle.
   getDriver: jest.fn(() => null),
   getSessionId: jest.fn(() => undefined),
-  getPlatformName: jest.fn(() => 'Android'),
-  isXCUITestDriverSession: jest.fn(() => false),
+  getPlatformName: mockGetPlatformName,
+  isXCUITestDriverSession: mockIsXCUITestDriverSession,
   PLATFORM: {ios: 'iOS', android: 'Android'},
 }));
 
@@ -26,12 +28,14 @@ jest.unstable_mockModule('../../../tools/app-management/list-apps.js', () => ({
 
 const {resolveAppId} = await import('../../../tools/app-management/resolve-app-id.js');
 
-describe('resolveAppId on a persisted session', () => {
-  beforeEach(() => {
-    jest.clearAllMocks();
-    mockListAppsFromDevice.mockResolvedValue([{packageName: 'com.example.calc', appName: 'Calculator'}]);
-  });
+beforeEach(() => {
+  jest.clearAllMocks();
+  mockGetPlatformName.mockReturnValue('Android');
+  mockIsXCUITestDriverSession.mockReturnValue(false);
+  mockListAppsFromDevice.mockResolvedValue([{packageName: 'com.example.calc', appName: 'Calculator'}]);
+});
 
+describe('resolveAppId on a persisted session', () => {
   test('rehydrates the session instead of failing on an empty driver cache', async () => {
     mockResolveDriver.mockResolvedValue({ok: true, driver: rehydratedDriver});
 
@@ -48,3 +52,30 @@ describe('resolveAppId on a persisted session', () => {
     expect(mockListAppsFromDevice).not.toHaveBeenCalled();
   });
 });
+
+describe('resolveAppId on a real iOS device', () => {
+  const deviceDriver = {isSimulator: () => false};
+
+  beforeEach(() => {
+    mockGetPlatformName.mockReturnValue('iOS');
+    mockIsXCUITestDriverSession.mockReturnValue(true);
+    mockResolveDriver.mockResolvedValue({ok: true, driver: deviceDriver});
+  });
+
+  test('keeps the apps that were listed when only one app type fails', async () => {
+    mockListAppsFromDevice
+      .mockResolvedValueOnce([{packageName: 'com.example.calc', appName: 'Calculator'}])
+      .mockRejectedValueOnce(new Error('System app list unavailable'));
+
+    await expect(resolveAppId('Calculator', 'device-1')).resolves.toBe('com.example.calc');
+  });
+
+  test('reports the device failure instead of caching an empty app list', async () => {
+    mockListAppsFromDevice.mockRejectedValue(new Error('Could not list applications on the device'));
+
+    await expect(resolveAppId('Calculator', 'device-2')).rejects.toThrow(/Could not list applications/);
+
+    mockListAppsFromDevice.mockResolvedValue([{packageName: 'com.example.calc', appName: 'Calculator'}]);
+    await expect(resolveAppId('Calculator', 'device-2')).resolves.toBe('com.example.calc');
+  });
+});

src/tools/app-management/resolve-app-id.ts

@@ -107,6 +107,10 @@ async function getInstalledApps(sessionId?: string): Promise<{packageName: strin
       listAppsFromDevice(driver, 'User'),
       listAppsFromDevice(driver, 'System'),
     ]);
+    const failures = results.filter((result) => result.status === 'rejected');
+    if (failures.length === results.length) {
+      throw failures[0].reason;
+    }
     const seen = new Set<string>();
     apps = [];
     for (const result of results) {