[flutter_tools] support enable-experiment in flutter analyze (#54613)

packages/flutter_tools/lib/src/base/terminal.dart

@@ -168,7 +168,7 @@ class AnsiTerminal implements Terminal {
   static String colorCode(TerminalColor color) => _colorMap[color];
 
   @override
-  bool get supportsColor => _platform.stdoutSupportsAnsi ?? false;
+  bool get supportsColor => _platform?.stdoutSupportsAnsi ?? false;
 
   // Assume unicode emojis are supported when not on Windows.
   // If we are on Windows, unicode emojis are supported in Windows Terminal,

packages/flutter_tools/lib/src/commands/analyze.dart

@@ -30,6 +30,7 @@ class AnalyzeCommand extends FlutterCommand {
        _logger = logger,
        _terminal = terminal,
        _platform = platform {
+    addEnableExperimentation(verbose: verboseHelp);
     argParser.addFlag('flutter-repo',
         negatable: false,
         help: 'Include all the examples and tests from the Flutter repository.',
@@ -118,6 +119,7 @@ class AnalyzeCommand extends FlutterCommand {
         platform: _platform,
         processManager: _processManager,
         terminal: _terminal,
+        experiments: stringsArg('enable-experiment'),
       ).analyze();
     } else {
       await AnalyzeOnce(
@@ -132,6 +134,7 @@ class AnalyzeCommand extends FlutterCommand {
         platform: _platform,
         processManager: _processManager,
         terminal: _terminal,
+        experiments: stringsArg('enable-experiment'),
       ).analyze();
     }
     return FlutterCommandResult.success();

packages/flutter_tools/lib/src/commands/analyze_base.dart

@@ -28,6 +28,7 @@ abstract class AnalyzeBase {
     @required this.platform,
     @required this.processManager,
     @required this.terminal,
+    @required this.experiments,
   });
 
   /// The parsed argument results for execution.
@@ -46,6 +47,8 @@ abstract class AnalyzeBase {
   final Platform platform;
   @protected
   final AnsiTerminal terminal;
+  @protected
+  final List<String> experiments;
 
   /// Called by [AnalyzeCommand] to start the analysis process.
   Future<void> analyze();

packages/flutter_tools/lib/src/commands/analyze_continuously.dart

@@ -27,6 +27,7 @@ class AnalyzeContinuously extends AnalyzeBase {
     @required AnsiTerminal terminal,
     @required Platform platform,
     @required ProcessManager processManager,
+    @required List<String> experiments,
   }) : super(
         argResults,
         repoPackages: repoPackages,
@@ -36,6 +37,7 @@ class AnalyzeContinuously extends AnalyzeBase {
         platform: platform,
         terminal: terminal,
         processManager: processManager,
+        experiments: experiments,
       );
 
   String analysisTarget;
@@ -74,6 +76,7 @@ class AnalyzeContinuously extends AnalyzeBase {
       platform: platform,
       processManager: processManager,
       terminal: terminal,
+      experiments: experiments,
     );
     server.onAnalyzing.listen((bool isAnalyzing) => _handleAnalysisStatus(server, isAnalyzing));
     server.onErrors.listen(_handleAnalysisErrors);

packages/flutter_tools/lib/src/commands/analyze_once.dart

@@ -31,6 +31,7 @@ class AnalyzeOnce extends AnalyzeBase {
     @required Platform platform,
     @required ProcessManager processManager,
     @required AnsiTerminal terminal,
+    @required List<String> experiments,
     this.workingDirectory,
   }) : super(
         argResults,
@@ -41,6 +42,7 @@ class AnalyzeOnce extends AnalyzeBase {
         platform: platform,
         processManager: processManager,
         terminal: terminal,
+        experiments: experiments,
       );
 
   /// The working directory for testing analysis using dartanalyzer.
@@ -98,6 +100,7 @@ class AnalyzeOnce extends AnalyzeBase {
       logger: logger,
       processManager: processManager,
       terminal: terminal,
+      experiments: experiments,
     );
 
     StreamSubscription<bool> subscription;

packages/flutter_tools/lib/src/dart/analysis.dart

@@ -24,12 +24,14 @@ class AnalysisServer {
     @required ProcessManager processManager,
     @required Logger logger,
     @required Platform platform,
-    @required AnsiTerminal terminal,
+    @required Terminal terminal,
+    @required List<String> experiments,
   }) : _fileSystem = fileSystem,
        _processManager = processManager,
        _logger = logger,
        _platform = platform,
-       _terminal = terminal;
+       _terminal = terminal,
+       _experiments = experiments;
 
   final String sdkPath;
   final List<String> directories;
@@ -37,7 +39,8 @@ class AnalysisServer {
   final ProcessManager _processManager;
   final Logger _logger;
   final Platform _platform;
-  final AnsiTerminal _terminal;
+  final Terminal _terminal;
+  final List<String> _experiments;
 
   Process _process;
   final StreamController<bool> _analyzingController =
@@ -49,11 +52,20 @@ class AnalysisServer {
   int _id = 0;
 
   Future<void> start() async {
-    final String snapshot =
-        _fileSystem.path.join(sdkPath, 'bin/snapshots/analysis_server.dart.snapshot');
+    final String snapshot = _fileSystem.path.join(
+      sdkPath,
+      'bin',
+      'snapshots',
+      'analysis_server.dart.snapshot',
+    );
     final List<String> command = <String>[
       _fileSystem.path.join(sdkPath, 'bin', 'dart'),
       snapshot,
+      for (String experiment in _experiments)
+        ...<String>[
+          '--enable-experiment',
+          experiment,
+        ],
       '--disable-server-feature-completion',
       '--disable-server-feature-search',
       '--sdk',
@@ -181,14 +193,14 @@ enum _AnalysisSeverity {
 class AnalysisError implements Comparable<AnalysisError> {
   AnalysisError(this.json, {
     @required Platform platform,
-    @required AnsiTerminal terminal,
+    @required Terminal terminal,
     @required FileSystem fileSystem,
   }) : _platform = platform,
        _terminal = terminal,
        _fileSystem = fileSystem;
 
   final Platform _platform;
-  final AnsiTerminal _terminal;
+  final Terminal _terminal;
   final FileSystem _fileSystem;
 
   static final Map<String, _AnalysisSeverity> _severityMap = <String, _AnalysisSeverity>{

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -462,6 +462,17 @@ abstract class FlutterCommand extends Command<void> {
     );
   }
 
+  void addEnableExperimentation({ bool verbose }) {
+    argParser.addMultiOption(
+      FlutterOptions.kEnableExperiment,
+      help:
+        'The name of an experimental Dart feature to enable. For more info '
+        'see: https://github.com/dart-lang/sdk/blob/master/docs/process/'
+        'experimental-flags.md',
+      hide: !verbose,
+    );
+  }
+
   set defaultBuildMode(BuildMode value) {
     _defaultBuildMode = value;
   }

packages/flutter_tools/test/commands.shard/hermetic/analyze_continuously_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
@@ -72,6 +73,7 @@ void main() {
         processManager: processManager,
         logger: logger,
         terminal: terminal,
+        experiments: <String>[],
       );
 
       int errorCount = 0;
@@ -96,6 +98,7 @@ void main() {
       processManager: processManager,
       logger: logger,
       terminal: terminal,
+      experiments: <String>[],
     );
 
     int errorCount = 0;
@@ -119,6 +122,7 @@ void main() {
       processManager: processManager,
       logger: logger,
       terminal: terminal,
+      experiments: <String>[],
     );
 
     int errorCount = 0;
@@ -130,4 +134,39 @@ void main() {
     await onDone;
     expect(errorCount, 0);
   });
+
+  testWithoutContext('Can forward null-safety experiments to the AnalysisServer', () async {
+    final Completer<void> completer = Completer<void>();
+    final StreamController<List<int>> stdin = StreamController<List<int>>();
+    const String fakeSdkPath = 'dart-sdk';
+    final FakeCommand fakeCommand = FakeCommand(
+      command: const <String>[
+        'dart-sdk/bin/dart',
+        'dart-sdk/bin/snapshots/analysis_server.dart.snapshot',
+        '--enable-experiment',
+        'non-nullable',
+        '--disable-server-feature-completion',
+        '--disable-server-feature-search',
+        '--sdk',
+        'dart-sdk',
+      ],
+      completer: completer,
+      stdin: IOSink(stdin.sink),
+    );
+
+    server = AnalysisServer(fakeSdkPath, <String>[''],
+      fileSystem: MemoryFileSystem.test(),
+      platform: FakePlatform(),
+      processManager: FakeProcessManager.list(<FakeCommand>[
+        fakeCommand,
+      ]),
+      logger: BufferLogger.test(),
+      terminal: Terminal.test(),
+      experiments: <String>[
+        'non-nullable'
+      ],
+    );
+
+    await server.start();
+  });
 }

packages/flutter_tools/test/commands.shard/hermetic/analyze_test.dart

@@ -11,54 +11,44 @@ import '../../src/common.dart';
 const String _kFlutterRoot = '/data/flutter';
 
 void main() {
-  FileSystem fs;
-  Directory tempDir;
-
-  setUp(() {
-    fs = MemoryFileSystem();
-    fs.directory(_kFlutterRoot).createSync(recursive: true);
+  testWithoutContext('analyze inRepo', () {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    fileSystem.directory(_kFlutterRoot).createSync(recursive: true);
+    final Directory tempDir = fileSystem.systemTempDirectory
+      .createTempSync('flutter_analysis_test.');
     Cache.flutterRoot = _kFlutterRoot;
-    tempDir = fs.systemTempDirectory.createTempSync('flutter_analysis_test.');
-  });
 
-  tearDown(() {
-    tryToDelete(tempDir);
-  });
+    // Absolute paths
+    expect(inRepo(<String>[tempDir.path], fileSystem), isFalse);
+    expect(inRepo(<String>[fileSystem.path.join(tempDir.path, 'foo')], fileSystem), isFalse);
+    expect(inRepo(<String>[Cache.flutterRoot], fileSystem), isTrue);
+    expect(inRepo(<String>[fileSystem.path.join(Cache.flutterRoot, 'foo')], fileSystem), isTrue);
 
-  group('analyze', () {
-    testWithoutContext('inRepo', () {
-      bool inRepo(List<String> fileList) {
-        if (fileList == null || fileList.isEmpty) {
-          fileList = <String>[fs.path.current];
-        }
-        final String root = fs.path.normalize(fs.path.absolute(Cache.flutterRoot));
-        final String prefix = root + fs.path.separator;
-        for (String file in fileList) {
-          file = fs.path.normalize(fs.path.absolute(file));
-          if (file == root || file.startsWith(prefix)) {
-            return true;
-          }
-        }
-        return false;
-      }
+    // Relative paths
+    fileSystem.currentDirectory = Cache.flutterRoot;
+    expect(inRepo(<String>['.'], fileSystem), isTrue);
+    expect(inRepo(<String>['foo'], fileSystem), isTrue);
+    fileSystem.currentDirectory = tempDir.path;
+    expect(inRepo(<String>['.'], fileSystem), isFalse);
+    expect(inRepo(<String>['foo'], fileSystem), isFalse);
 
-      // Absolute paths
-      expect(inRepo(<String>[tempDir.path]), isFalse);
-      expect(inRepo(<String>[fs.path.join(tempDir.path, 'foo')]), isFalse);
-      expect(inRepo(<String>[Cache.flutterRoot]), isTrue);
-      expect(inRepo(<String>[fs.path.join(Cache.flutterRoot, 'foo')]), isTrue);
-
-      // Relative paths
-      fs.currentDirectory = Cache.flutterRoot;
-      expect(inRepo(<String>['.']), isTrue);
-      expect(inRepo(<String>['foo']), isTrue);
-      fs.currentDirectory = tempDir.path;
-      expect(inRepo(<String>['.']), isFalse);
-      expect(inRepo(<String>['foo']), isFalse);
-
-      // Ensure no exceptions
-      inRepo(null);
-      inRepo(<String>[]);
-    });
+    // Ensure no exceptions
+    inRepo(null, fileSystem);
+    inRepo(<String>[], fileSystem);
   });
 }
+
+bool inRepo(List<String> fileList, FileSystem fileSystem) {
+  if (fileList == null || fileList.isEmpty) {
+    fileList = <String>[fileSystem.path.current];
+  }
+  final String root = fileSystem.path.normalize(fileSystem.path.absolute(Cache.flutterRoot));
+  final String prefix = root + fileSystem.path.separator;
+  for (String file in fileList) {
+    file = fileSystem.path.normalize(fileSystem.path.absolute(file));
+    if (file == root || file.startsWith(prefix)) {
+      return true;
+    }
+  }
+  return false;
+}

packages/flutter_tools/test/commands.shard/permeable/analyze_once_test.dart

@@ -304,6 +304,32 @@ StringBuffer bar = StringBuffer('baz');
     }
   });
 
+  testUsingContext('analyze once supports analyzing null-safe code', () async {
+    const String contents = '''
+int? bar;
+''';
+    final Directory tempDir = fileSystem.systemTempDirectory.createTempSync('flutter_analyze_once_test_null_safety.');
+    _createDotPackages(tempDir.path);
+
+    tempDir.childFile('main.dart').writeAsStringSync(contents);
+    try {
+      await runCommand(
+        command: AnalyzeCommand(
+          workingDirectory: fileSystem.directory(tempDir),
+          platform: _kNoColorTerminalPlatform,
+          fileSystem: fileSystem,
+          logger: logger,
+          processManager: processManager,
+          terminal: terminal,
+        ),
+        arguments: <String>['analyze', '--no-pub', '--enable-experiment=non-nullable'],
+        statusTextContains: <String>['No issues found!'],
+      );
+    } finally {
+      tryToDelete(tempDir);
+    }
+  });
+
   testUsingContext('analyze once returns no issues for todo comments', () async {
     const String contents = '''
 // TODO(foobar):

packages/flutter_tools/test/src/fake_process_manager.dart

@@ -28,6 +28,7 @@ class FakeCommand {
     this.stdout = '',
     this.stderr = '',
     this.completer,
+    this.stdin,
   }) : assert(command != null),
        assert(duration != null),
        assert(exitCode != null);
@@ -82,6 +83,10 @@ class FakeCommand {
   /// resolves.
   final Completer<void> completer;
 
+  /// An optional stdin sink that will be exposed through the resulting
+  /// [FakeProcess].
+  final IOSink stdin;
+
   void _matches(List<String> command, String workingDirectory, Map<String, String> environment) {
     expect(command, equals(this.command));
     if (this.workingDirectory != null) {
@@ -198,7 +203,7 @@ abstract class FakeProcessManager implements ProcessManager {
       fakeCommand.onRun,
       _pid,
       fakeCommand.stderr,
-      null, // stdin
+      fakeCommand.stdin,
       fakeCommand.stdout,
       fakeCommand.completer,
     );