Handle case of a connected unpaired iOS device (#38629)

Fixes https://github.com/flutter/flutter/issues/36789
Fixes https://github.com/flutter/flutter/issues/37000

https://github.com/flutter/flutter/issues/36524
https://github.com/flutter/flutter/issues/24600

packages/flutter_tools/lib/src/ios/devices.dart

@@ -20,6 +20,7 @@ import '../device.dart';
 import '../globals.dart';
 import '../project.dart';
 import '../protocol_discovery.dart';
+import '../reporting/reporting.dart';
 import 'code_signing.dart';
 import 'ios_workflow.dart';
 import 'mac.dart';
@@ -185,6 +186,9 @@ class IOSDevice extends Device {
       } on IOSDeviceNotFoundError catch (error) {
         // Unable to find device with given udid. Possibly a network device.
         printTrace('Error getting attached iOS device: $error');
+      } on IOSDeviceNotTrustedError catch (error) {
+        printTrace('Error getting attached iOS device information: $error');
+        UsageEvent('device', 'ios-trust-failure').send();
       }
     }
     return devices;

packages/flutter_tools/lib/src/ios/mac.dart

@@ -34,7 +34,7 @@ IMobileDevice get iMobileDevice => context.get<IMobileDevice>();
 /// Specialized exception for expected situations where the ideviceinfo
 /// tool responds with exit code 255 / 'No device found' message
 class IOSDeviceNotFoundError implements Exception {
-  IOSDeviceNotFoundError(this.message);
+  const IOSDeviceNotFoundError(this.message);
 
   final String message;
 
@@ -42,6 +42,56 @@ class IOSDeviceNotFoundError implements Exception {
   String toString() => message;
 }
 
+/// Exception representing an attempt to find information on an iOS device
+/// that failed because the user had not paired the device with the host yet.
+class IOSDeviceNotTrustedError implements Exception {
+  const IOSDeviceNotTrustedError(this.message, this.lockdownCode);
+
+  /// The error message to show to the user.
+  final String message;
+
+  /// The associated `lockdownd` error code.
+  final LockdownReturnCode lockdownCode;
+
+  @override
+  String toString() => '$message (lockdownd error code ${lockdownCode.code})';
+}
+
+/// Class specifying possible return codes from `lockdownd`.
+///
+/// This contains only a subset of the return codes that `lockdownd` can return,
+/// as we only care about a limited subset. These values should be kept in sync with
+/// https://github.com/libimobiledevice/libimobiledevice/blob/26373b3/include/libimobiledevice/lockdown.h#L37
+class LockdownReturnCode {
+  const LockdownReturnCode._(this.code);
+
+  /// Creates a new [LockdownReturnCode] from the specified OS exit code.
+  ///
+  /// If the [code] maps to one of the known codes, a `const` instance will be
+  /// returned.
+  factory LockdownReturnCode.fromCode(int code) {
+    final Map<int, LockdownReturnCode> knownCodes = <int, LockdownReturnCode>{
+      pairingDialogResponsePending.code: pairingDialogResponsePending,
+      invalidHostId.code: invalidHostId,
+    };
+
+    return knownCodes.containsKey(code) ? knownCodes[code] : LockdownReturnCode._(code);
+  }
+
+  /// The OS exit code.
+  final int code;
+
+  /// Error code indicating that the pairing dialog has been shown to the user,
+  /// and the user has not yet responded as to whether to trust the host.
+  static const LockdownReturnCode pairingDialogResponsePending = LockdownReturnCode._(19);
+
+  /// Error code indicating that the host is not trusted.
+  ///
+  /// This can happen if the user explicitly says "do not trust this  computer"
+  /// or if they revoke all trusted computers in the device settings.
+  static const LockdownReturnCode invalidHostId = LockdownReturnCode._(21);
+}
+
 class IMobileDevice {
   IMobileDevice()
       : _ideviceIdPath = artifacts.getArtifactPath(Artifact.ideviceId, platform: TargetPlatform.ios)
@@ -159,7 +209,21 @@ class IMobileDevice {
         ),
       );
       if (result.exitCode == 255 && result.stdout != null && result.stdout.contains('No device found'))
-        throw IOSDeviceNotFoundError('ideviceinfo could not find device:\n${result.stdout}');
+        throw IOSDeviceNotFoundError('ideviceinfo could not find device:\n${result.stdout}. Try unlocking attached devices.');
+      if (result.exitCode == 255 && result.stderr != null && result.stderr.contains('Could not connect to lockdownd')) {
+        if (result.stderr.contains('error code -${LockdownReturnCode.pairingDialogResponsePending.code}')) {
+          throw const IOSDeviceNotTrustedError(
+            'Device info unavailable. Is the device asking to "Trust This Computer?"',
+            LockdownReturnCode.pairingDialogResponsePending,
+          );
+        }
+        if (result.stderr.contains('error code -${LockdownReturnCode.invalidHostId.code}')) {
+          throw const IOSDeviceNotTrustedError(
+            'Device info unavailable. Device pairing "trust" may have been revoked.',
+            LockdownReturnCode.invalidHostId,
+          );
+        }
+      }
       if (result.exitCode != 0)
         throw ToolExit('ideviceinfo returned an error:\n${result.stderr}');
       return result.stdout.trim();

packages/flutter_tools/test/general.shard/ios/devices_test.dart

@@ -371,7 +371,7 @@ f577a7903cc54959be2e34bc4f7f80b7009efcf4
       when(iMobileDevice.getInfoForDevice('98206e7a4afd4aedaff06e687594e089dede3c44', 'DeviceName'))
           .thenAnswer((_) => Future<String>.value('La tele me regarde'));
       when(iMobileDevice.getInfoForDevice('f577a7903cc54959be2e34bc4f7f80b7009efcf4', 'DeviceName'))
-          .thenThrow(IOSDeviceNotFoundError('Device not found'));
+          .thenThrow(const IOSDeviceNotFoundError('Device not found'));
       final List<IOSDevice> devices = await IOSDevice.getAttachedDevices();
       expect(devices, hasLength(1));
       expect(devices[0].id, '98206e7a4afd4aedaff06e687594e089dede3c44');

packages/flutter_tools/test/general.shard/ios/mac_test.dart

@@ -113,6 +113,69 @@ void main() {
       Artifacts: () => mockArtifacts,
     });
 
+    testUsingContext('getInfoForDevice throws IOSDeviceNotFoundError when user has not yet trusted the host', () async {
+      when(mockArtifacts.getArtifactPath(Artifact.ideviceinfo, platform: anyNamed('platform'))).thenReturn(ideviceInfoPath);
+      when(mockProcessManager.run(
+        <String>[ideviceInfoPath, '-u', 'foo', '-k', 'bar'],
+        environment: <String, String>{'DYLD_LIBRARY_PATH': libimobiledevicePath},
+      )).thenAnswer((_) {
+        final ProcessResult result = ProcessResult(
+          1,
+          255,
+          '',
+          'ERROR: Could not connect to lockdownd, error code -${LockdownReturnCode.pairingDialogResponsePending.code}',
+        );
+        return Future<ProcessResult>.value(result);
+      });
+      expect(() async => await iMobileDevice.getInfoForDevice('foo', 'bar'), throwsA(isInstanceOf<IOSDeviceNotTrustedError>()));
+    }, overrides: <Type, Generator>{
+      ProcessManager: () => mockProcessManager,
+      Cache: () => mockCache,
+      Artifacts: () => mockArtifacts,
+    });
+
+    testUsingContext('getInfoForDevice throws ToolExit lockdownd fails for unknown reason', () async {
+      when(mockArtifacts.getArtifactPath(Artifact.ideviceinfo, platform: anyNamed('platform'))).thenReturn(ideviceInfoPath);
+      when(mockProcessManager.run(
+        <String>[ideviceInfoPath, '-u', 'foo', '-k', 'bar'],
+        environment: <String, String>{'DYLD_LIBRARY_PATH': libimobiledevicePath},
+      )).thenAnswer((_) {
+        final ProcessResult result = ProcessResult(
+          1,
+          255,
+          '',
+          'ERROR: Could not connect to lockdownd, error code -12345',
+        );
+        return Future<ProcessResult>.value(result);
+      });
+      expect(() async => await iMobileDevice.getInfoForDevice('foo', 'bar'), throwsToolExit());
+    }, overrides: <Type, Generator>{
+      ProcessManager: () => mockProcessManager,
+      Cache: () => mockCache,
+      Artifacts: () => mockArtifacts,
+    });
+
+    testUsingContext('getInfoForDevice throws IOSDeviceNotFoundError when host trust is revoked', () async {
+      when(mockArtifacts.getArtifactPath(Artifact.ideviceinfo, platform: anyNamed('platform'))).thenReturn(ideviceInfoPath);
+      when(mockProcessManager.run(
+        <String>[ideviceInfoPath, '-u', 'foo', '-k', 'bar'],
+        environment: <String, String>{'DYLD_LIBRARY_PATH': libimobiledevicePath},
+      )).thenAnswer((_) {
+        final ProcessResult result = ProcessResult(
+          1,
+          255,
+          '',
+          'ERROR: Could not connect to lockdownd, error code -${LockdownReturnCode.invalidHostId.code}',
+        );
+        return Future<ProcessResult>.value(result);
+      });
+      expect(() async => await iMobileDevice.getInfoForDevice('foo', 'bar'), throwsA(isInstanceOf<IOSDeviceNotTrustedError>()));
+    }, overrides: <Type, Generator>{
+      ProcessManager: () => mockProcessManager,
+      Cache: () => mockCache,
+      Artifacts: () => mockArtifacts,
+    });
+
     group('screenshot', () {
       final String outputPath = fs.path.join('some', 'test', 'path', 'image.png');
       MockProcessManager mockProcessManager;