Do not throw when trying to discover a fuchsia device and the sshConfig is invalid (#52858)

* Do not throw when trying to discover a fuchsia device and the sshConfig is invalid

packages/flutter_tools/lib/src/fuchsia/fuchsia_device.dart

@@ -423,11 +423,18 @@ class FuchsiaDevice extends Device {
   TargetPlatform _targetPlatform;
 
   Future<TargetPlatform> _queryTargetPlatform() async {
+    const TargetPlatform defaultTargetPlatform = TargetPlatform.fuchsia_arm64;
+    if (!globals.fuchsiaArtifacts.hasSshConfig) {
+      globals.printTrace('Could not determine Fuchsia target platform because '
+                 'Fuchsia ssh configuration is missing.\n'
+                 'Defaulting to arm64.');
+      return defaultTargetPlatform;
+    }
     final RunResult result = await shell('uname -m');
     if (result.exitCode != 0) {
       globals.printError('Could not determine Fuchsia target platform type:\n$result\n'
                  'Defaulting to arm64.');
-      return TargetPlatform.fuchsia_arm64;
+      return defaultTargetPlatform;
     }
     final String machine = result.stdout.trim();
     switch (machine) {
@@ -438,7 +445,7 @@ class FuchsiaDevice extends Device {
       default:
         globals.printError('Unknown Fuchsia target platform "$machine". '
                    'Defaulting to arm64.');
-        return TargetPlatform.fuchsia_arm64;
+        return defaultTargetPlatform;
     }
   }
 
@@ -480,16 +487,22 @@ class FuchsiaDevice extends Device {
 
   @override
   Future<String> get sdkNameAndVersion async {
+    const String defaultName = 'Fuchsia';
+    if (!globals.fuchsiaArtifacts.hasSshConfig) {
+      globals.printTrace('Could not determine Fuchsia sdk name or version '
+                 'because Fuchsia ssh configuration is missing.');
+      return defaultName;
+    }
     const String versionPath = '/pkgfs/packages/build-info/0/data/version';
     final RunResult catResult = await shell('cat $versionPath');
     if (catResult.exitCode != 0) {
       globals.printTrace('Failed to cat $versionPath: ${catResult.stderr}');
-      return 'Fuchsia';
+      return defaultName;
     }
     final String version = catResult.stdout.trim();
     if (version.isEmpty) {
       globals.printTrace('$versionPath was empty');
-      return 'Fuchsia';
+      return defaultName;
     }
     return 'Fuchsia $version';
   }

packages/flutter_tools/lib/src/fuchsia/fuchsia_sdk.dart

@@ -156,4 +156,7 @@ class FuchsiaArtifacts {
 
   /// The pm tool.
   final File pm;
+
+  /// Returns true if the [sshConfig] file is not null and exists.
+  bool get hasSshConfig => sshConfig != null && sshConfig.existsSync();
 }

packages/flutter_tools/test/general.shard/fuchsia/fuchsia_device_test.dart

@@ -43,6 +43,7 @@ void main() {
     setUp(() {
       memoryFileSystem = MemoryFileSystem();
       sshConfig = MockFile();
+      when(sshConfig.existsSync()).thenReturn(true);
       when(sshConfig.absolute).thenReturn(sshConfig);
     });
 
@@ -115,6 +116,15 @@ void main() {
       ProcessManager: () => FakeProcessManager.any(),
     });
 
+    testUsingContext('targetPlatform does not throw when sshConfig is missing', () async {
+      final FuchsiaDevice device = FuchsiaDevice('123');
+      expect(await device.targetPlatform, TargetPlatform.fuchsia_arm64);
+    }, overrides: <Type, Generator>{
+      FuchsiaArtifacts: () => FuchsiaArtifacts(sshConfig: null),
+      FuchsiaSdk: () => MockFuchsiaSdk(),
+      ProcessManager: () => MockProcessManager(),
+    });
+
     testUsingContext('targetPlatform arm64 works', () async {
       when(globals.processManager.run(any)).thenAnswer((Invocation _) async {
         return ProcessResult(1, 0, 'aarch64', '');
@@ -888,6 +898,7 @@ void main() {
 
     setUp(() {
       sshConfig = MockFile();
+      when(sshConfig.existsSync()).thenReturn(true);
       when(sshConfig.absolute).thenReturn(sshConfig);
 
       mockSuccessProcessManager = MockProcessManager();
@@ -915,6 +926,15 @@ void main() {
       when<String>(emptyStdoutProcessResult.stderr as String).thenReturn('');
     });
 
+    testUsingContext('does not throw on non-existant ssh config', () async {
+      final FuchsiaDevice device = FuchsiaDevice('123');
+      expect(await device.sdkNameAndVersion, equals('Fuchsia'));
+    }, overrides: <Type, Generator>{
+      ProcessManager: () => mockSuccessProcessManager,
+      FuchsiaArtifacts: () => FuchsiaArtifacts(sshConfig: null),
+      FuchsiaSdk: () => MockFuchsiaSdk(),
+    });
+
     testUsingContext('returns what we get from the device on success', () async {
       final FuchsiaDevice device = FuchsiaDevice('123');
       expect(await device.sdkNameAndVersion, equals('Fuchsia version'));