Check if simctl is installed before trying to list devices or runtimes (#163895)

After https://github.com/flutter/flutter/pull/163785 there was still an
unexpected `xcrun simctl` output on a machine with Xcode only half
installed https://github.com/flutter/flutter/issues/161655.

Check `simctl` is installed before trying to list booted simulator
devices or runtimes.

Should address https://github.com/flutter/flutter/issues/161655.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

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

@@ -66,7 +66,7 @@ class IOSSimulatorUtils {
   final Xcode _xcode;
 
   Future<List<IOSSimulator>> getAttachedDevices() async {
-    if (!_xcode.isInstalledAndMeetsVersionCheck) {
+    if (!_xcode.isInstalledAndMeetsVersionCheck || !_xcode.isSimctlInstalled) {
       return <IOSSimulator>[];
     }
 
@@ -96,7 +96,7 @@ class IOSSimulatorUtils {
   }
 
   Future<List<IOSSimulatorRuntime>> getAvailableIOSRuntimes() async {
-    if (!_xcode.isInstalledAndMeetsVersionCheck) {
+    if (!_xcode.isInstalledAndMeetsVersionCheck || !_xcode.isSimctlInstalled) {
       return <IOSSimulatorRuntime>[];
     }
 

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

@@ -894,7 +894,10 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text''',
 
     late FakeProcessManager fakeProcessManager;
     Xcode xcode;
+    Xcode xcodeBadSimctl;
     late SimControl simControl;
+    late IOSSimulatorUtils simulatorUtils;
+    late IOSSimulatorUtils simulatorUtilsBadSimctl;
     late BufferLogger logger;
     const String deviceId = 'smart-phone';
     const String appId = 'flutterApp';
@@ -902,8 +905,32 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text''',
     setUp(() {
       fakeProcessManager = FakeProcessManager.empty();
       xcode = Xcode.test(processManager: FakeProcessManager.any());
+
+      final FakeProcessManager fakeProcessManagerBadSimctl = FakeProcessManager.list(<FakeCommand>[
+        const FakeCommand(command: <String>['which', 'sysctl']),
+        const FakeCommand(
+          command: <String>['sysctl', 'hw.optional.arm64'],
+          stdout: 'hw.optional.arm64: 0',
+        ),
+        const FakeCommand(
+          command: <String>['xcrun', 'simctl', 'list', 'devices', 'booted'],
+          stderr: 'failed to run',
+          exitCode: 1,
+        ),
+      ]);
+      xcodeBadSimctl = Xcode.test(processManager: fakeProcessManagerBadSimctl);
       logger = BufferLogger.test();
       simControl = SimControl(logger: logger, processManager: fakeProcessManager, xcode: xcode);
+      simulatorUtils = IOSSimulatorUtils(
+        logger: logger,
+        processManager: fakeProcessManager,
+        xcode: xcode,
+      );
+      simulatorUtilsBadSimctl = IOSSimulatorUtils(
+        logger: logger,
+        processManager: fakeProcessManager,
+        xcode: xcodeBadSimctl,
+      );
     });
 
     testWithoutContext('getConnectedDevices succeeds', () async {
@@ -933,6 +960,33 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text''',
       expect(fakeProcessManager, hasNoRemainingExpectations);
     });
 
+    testWithoutContext('IOSSimulatorUtils.getAttachedDevices succeeds', () async {
+      fakeProcessManager.addCommand(
+        const FakeCommand(
+          command: <String>['xcrun', 'simctl', 'list', 'devices', 'booted', 'iOS', '--json'],
+          stdout: validSimControlOutput,
+        ),
+      );
+
+      final List<IOSSimulator> devices = await simulatorUtils.getAttachedDevices();
+
+      final IOSSimulator phone1 = devices[0];
+      expect(phone1.category, Category.mobile);
+      expect(phone1.name, 'iPhone 11');
+      expect(phone1.simulatorCategory, 'com.apple.CoreSimulator.SimRuntime.iOS-14-0');
+
+      final IOSSimulator phone2 = devices[1];
+      expect(phone2.category, Category.mobile);
+      expect(phone2.name, 'Phone w Watch');
+      expect(phone2.simulatorCategory, 'com.apple.CoreSimulator.SimRuntime.iOS-16-0');
+
+      final IOSSimulator phone3 = devices[2];
+      expect(phone3.category, Category.mobile);
+      expect(phone3.name, 'iPhone 13');
+      expect(phone3.simulatorCategory, 'com.apple.CoreSimulator.SimRuntime.iOS-16-0');
+      expect(fakeProcessManager, hasNoRemainingExpectations);
+    });
+
     testWithoutContext('getConnectedDevices handles bad simctl output', () async {
       fakeProcessManager.addCommand(
         const FakeCommand(
@@ -947,6 +1001,16 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text''',
       expect(fakeProcessManager, hasNoRemainingExpectations);
     });
 
+    testWithoutContext(
+      'IOSSimulatorUtils.getAttachedDevices handles simctl not properly installed',
+      () async {
+        final List<IOSSimulator> devices = await simulatorUtilsBadSimctl.getAttachedDevices();
+
+        expect(devices, isEmpty);
+        expect(fakeProcessManager, hasNoRemainingExpectations);
+      },
+    );
+
     testWithoutContext('sdkMajorVersion defaults to 11 when sdkNameAndVersion is junk', () async {
       final IOSSimulator iosSimulatorA = IOSSimulator(
         'x',
@@ -1186,6 +1250,17 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text''',
       expect(logger.errorText, contains('simctl returned non-JSON response:'));
       expect(fakeProcessManager, hasNoRemainingExpectations);
     });
+
+    testWithoutContext(
+      'IOSSimulatorUtils.getAvailableIOSRuntimes handles simctl not properly installed',
+      () async {
+        final List<IOSSimulatorRuntime> runtimes =
+            await simulatorUtilsBadSimctl.getAvailableIOSRuntimes();
+
+        expect(runtimes, isEmpty);
+        expect(fakeProcessManager, hasNoRemainingExpectations);
+      },
+    );
   });
 
   group('startApp', () {