Add MultiRootFileSystem to better support using --filesystem-root. (#82991)

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

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io' as io
+    show
+        Directory,
+        File,
+        FileStat,
+        FileSystemEntity,
+        FileSystemEntityType,
+        Link;
+
+import 'package:file/file.dart';
+import 'package:meta/meta.dart';
+import 'package:path/path.dart' as p; // flutter_ignore: package_path_import
+
+/// A [FileSystem] that wraps the [delegate] file system to create an overlay of
+/// files from multiple [roots].
+///
+/// Regular paths or `file:` URIs are resolved directly in the underlying file
+/// system, but URIs that use a special [scheme] are resolved by searching
+/// under a set of given roots in order.
+///
+/// For example, consider the following inputs:
+///
+///   - scheme is `multi-root`
+///   - the set of roots are `/a` and `/b`
+///   - the underlying file system contains files:
+///         /root_a/dir/only_a.dart
+///         /root_a/dir/both.dart
+///         /root_b/dir/only_b.dart
+///         /root_b/dir/both.dart
+///         /other/other.dart
+///
+/// Then:
+///
+///   - file:///other/other.dart is resolved as /other/other.dart
+///   - multi-root:///dir/only_a.dart is resolved as /root_a/dir/only_a.dart
+///   - multi-root:///dir/only_b.dart is resolved as /root_b/dir/only_b.dart
+///   - multi-root:///dir/both.dart is resolved as /root_a/dir/only_a.dart
+class MultiRootFileSystem extends ForwardingFileSystem {
+  MultiRootFileSystem({
+    required FileSystem delegate,
+    required String scheme,
+    required List<String> roots,
+  })   : assert(delegate != null),
+        assert(roots.isNotEmpty),
+        _scheme = scheme,
+        _roots = roots.map((String root) => delegate.path.normalize(root)).toList(),
+        super(delegate);
+
+  @visibleForTesting
+  FileSystem get fileSystem => delegate;
+
+  final String _scheme;
+  final List<String> _roots;
+
+  @override
+  File file(dynamic path) => MultiRootFile(
+    fileSystem: this,
+    delegate: delegate.file(_resolve(path)),
+  );
+
+  @override
+  Directory directory(dynamic path) => MultiRootDirectory(
+    fileSystem: this,
+    delegate: delegate.directory(_resolve(path)),
+  );
+
+  @override
+  Link link(dynamic path) => MultiRootLink(
+    fileSystem: this,
+    delegate: delegate.link(_resolve(path)),
+  );
+
+  @override
+  Future<io.FileStat> stat(String path) =>
+    delegate.stat(_resolve(path).toString());
+
+  @override
+  io.FileStat statSync(String path) =>
+    delegate.statSync(_resolve(path).toString());
+
+  @override
+  Future<bool> identical(String path1, String path2) =>
+    delegate.identical(_resolve(path1).toString(), _resolve(path2).toString());
+
+  @override
+  bool identicalSync(String path1, String path2) =>
+    delegate.identicalSync(_resolve(path1).toString(), _resolve(path2).toString());
+
+  @override
+  Future<io.FileSystemEntityType> type(String path, {bool followLinks = true}) =>
+    delegate.type(_resolve(path).toString(), followLinks: followLinks);
+
+  @override
+  io.FileSystemEntityType typeSync(String path, {bool followLinks = true}) =>
+    delegate.typeSync(_resolve(path).toString(), followLinks: followLinks);
+
+  // Caching the path context here and clearing when the currentDirectory setter
+  // is updated works since the flutter tool restricts usage of dart:io directly
+  // via the forbidden import tests. Otherwise, the path context's current
+  // working directory might get out of sync, leading to unexpected results from
+  // methods like `path.relative`.
+  @override
+  p.Context get path => _cachedPath ??= delegate.path;
+  p.Context? _cachedPath;
+
+  @override
+  set currentDirectory(dynamic path) {
+    _cachedPath = null;
+    delegate.currentDirectory = path;
+  }
+
+  /// If the path is a multiroot uri, resolve to the actual path of the
+  /// underlying file system. Otherwise, return as is.
+  dynamic _resolve(dynamic path) {
+    Uri uri;
+    if (path == null) {
+      return null;
+    } else if (path is String) {
+      uri = Uri.parse(path);
+    } else if (path is Uri) {
+      uri = path;
+    } else if (path is FileSystemEntity) {
+      uri = path.uri;
+    } else {
+      throw ArgumentError('Invalid type for "path": ${path?.runtimeType}');
+    }
+
+    if (!uri.hasScheme || uri.scheme != _scheme) {
+      return path;
+    }
+
+    String? firstRootPath;
+    final String relativePath = delegate.path.joinAll(uri.pathSegments);
+    for (final String root in _roots) {
+      final String pathWithRoot = delegate.path.join(root, relativePath);
+      if (delegate.typeSync(pathWithRoot, followLinks: false) !=
+          FileSystemEntityType.notFound) {
+        return pathWithRoot;
+      }
+      firstRootPath ??= pathWithRoot;
+    }
+
+    // If not found, construct the path with the first root.
+    return firstRootPath!;
+  }
+
+  Uri _toMultiRootUri(Uri uri) {
+    if (uri.scheme != 'file') {
+      return uri;
+    }
+
+    final p.Context pathContext = delegate.path;
+    final bool isWindows = pathContext.style == p.Style.windows;
+    final String path = uri.toFilePath(windows: isWindows);
+    for (final String root in _roots) {
+      if (path.startsWith('$root${pathContext.separator}')) {
+        String pathWithoutRoot = path.substring(root.length + 1);
+        if (isWindows) {
+          // Convert the path from Windows style
+          pathWithoutRoot = p.url.joinAll(pathContext.split(pathWithoutRoot));
+        }
+        return Uri.parse('$_scheme:///$pathWithoutRoot');
+      }
+    }
+    return uri;
+  }
+
+  @override
+  String toString() =>
+    'MultiRootFileSystem(scheme = $_scheme, roots = $_roots, delegate = $delegate)';
+}
+
+abstract class MultiRootFileSystemEntity<T extends FileSystemEntity,
+    D extends io.FileSystemEntity> extends ForwardingFileSystemEntity<T, D> {
+  MultiRootFileSystemEntity({
+    required this.fileSystem,
+    required this.delegate,
+  });
+
+  @override
+  final D delegate;
+
+  @override
+  final MultiRootFileSystem fileSystem;
+
+  @override
+  File wrapFile(io.File delegate) => MultiRootFile(
+    fileSystem: fileSystem,
+    delegate: delegate,
+  );
+
+  @override
+  Directory wrapDirectory(io.Directory delegate) => MultiRootDirectory(
+    fileSystem: fileSystem,
+    delegate: delegate,
+  );
+
+  @override
+  Link wrapLink(io.Link delegate) => MultiRootLink(
+    fileSystem: fileSystem,
+    delegate: delegate,
+  );
+
+  @override
+  Uri get uri => fileSystem._toMultiRootUri(delegate.uri);
+}
+
+class MultiRootFile extends MultiRootFileSystemEntity<File, io.File>
+    with ForwardingFile {
+  MultiRootFile({
+    required MultiRootFileSystem fileSystem,
+    required io.File delegate,
+  }) : super(
+    fileSystem: fileSystem,
+    delegate: delegate,
+  );
+
+  @override
+  String toString() =>
+    'MultiRootFile(fileSystem = $fileSystem, delegate = $delegate)';
+}
+
+class MultiRootDirectory
+    extends MultiRootFileSystemEntity<Directory, io.Directory>
+    with ForwardingDirectory<Directory> {
+  MultiRootDirectory({
+    required MultiRootFileSystem fileSystem,
+    required io.Directory delegate,
+  }) : super(
+    fileSystem: fileSystem,
+    delegate: delegate,
+  );
+
+  // For the childEntity methods, we first obtain an instance of the entity
+  // from the underlying file system, then invoke childEntity() on it, then
+  // wrap in the ErrorHandling version.
+  @override
+  Directory childDirectory(String basename) =>
+    fileSystem.directory(fileSystem.path.join(delegate.path, basename));
+
+  @override
+  File childFile(String basename) =>
+    fileSystem.file(fileSystem.path.join(delegate.path, basename));
+
+  @override
+  Link childLink(String basename) =>
+    fileSystem.link(fileSystem.path.join(delegate.path, basename));
+
+  @override
+  String toString() =>
+    'MultiRootDirectory(fileSystem = $fileSystem, delegate = $delegate)';
+}
+
+class MultiRootLink extends MultiRootFileSystemEntity<Link, io.Link>
+    with ForwardingLink {
+  MultiRootLink({
+    required MultiRootFileSystem fileSystem,
+    required io.Link delegate,
+  }) : super(
+    fileSystem: fileSystem,
+    delegate: delegate,
+  );
+
+  @override
+  String toString() =>
+    'MultiRootLink(fileSystem = $fileSystem, delegate = $delegate)';
+}

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

@@ -608,8 +608,8 @@ class RunCommand extends RunCommandBase {
       for (final Device device in devices)
         await FlutterDevice.create(
           device,
-          fileSystemRoots: stringsArg(FlutterOptions.kFileSystemRoot),
-          fileSystemScheme: stringArg(FlutterOptions.kFileSystemScheme),
+          fileSystemRoots: fileSystemRoots,
+          fileSystemScheme: fileSystemScheme,
           experimentalFlags: expFlags,
           target: targetFile,
           buildInfo: buildInfo,

packages/flutter_tools/lib/src/flutter_plugins.dart

@@ -36,14 +36,14 @@ void _renderTemplateToFile(String template, dynamic context, File file, Template
 
 Plugin _pluginFromPackage(String name, Uri packageRoot, Set<String> appDependencies, {FileSystem fileSystem}) {
   final FileSystem fs = fileSystem ?? globals.fs;
-  final String pubspecPath = fs.path.fromUri(packageRoot.resolve('pubspec.yaml'));
-  if (!fs.isFileSync(pubspecPath)) {
+  final File pubspecFile = fs.file(packageRoot.resolve('pubspec.yaml'));
+  if (!pubspecFile.existsSync()) {
     return null;
   }
   dynamic pubspec;
 
   try {
-    pubspec = loadYaml(fs.file(pubspecPath).readAsStringSync());
+    pubspec = loadYaml(pubspecFile.readAsStringSync());
   } on YamlException catch (err) {
     globals.printTrace('Failed to parse plugin manifest for $name: $err');
     // Do nothing, potentially not a plugin.

packages/flutter_tools/lib/src/resident_runner.dart

@@ -1070,7 +1070,7 @@ abstract class ResidentRunner extends ResidentHandlers {
     String dillOutputPath,
     this.machine = false,
     ResidentDevtoolsHandlerFactory devtoolsHandler = createDefaultHandler,
-  }) : mainPath = globals.fs.path.absolute(target),
+  }) : mainPath = globals.fs.file(target).absolute.path,
        packagesFilePath = debuggingOptions.buildInfo.packagesPath,
        projectRootPath = projectRootPath ?? globals.fs.currentDirectory.path,
        _dillOutputPath = dillOutputPath,

packages/flutter_tools/lib/src/run_hot.dart

@@ -1242,7 +1242,8 @@ class ProjectFileInvalidator {
       for (final Uri uri in urisToScan) {
         waitList.add(pool.withResource<void>(
           () => _fileSystem
-            .stat(uri.toFilePath(windows: _platform.isWindows))
+            .file(uri)
+            .stat()
             .then((FileStat stat) {
               final DateTime updatedAt = stat.modified;
               if (updatedAt != null && updatedAt.isAfter(lastCompiled)) {
@@ -1254,17 +1255,16 @@ class ProjectFileInvalidator {
       await Future.wait<void>(waitList);
     } else {
       for (final Uri uri in urisToScan) {
-        final DateTime updatedAt = _fileSystem.statSync(
-            uri.toFilePath(windows: _platform.isWindows)).modified;
+        final DateTime updatedAt = _fileSystem.file(uri).statSync().modified;
         if (updatedAt != null && updatedAt.isAfter(lastCompiled)) {
           invalidatedFiles.add(uri);
         }
       }
     }
     // We need to check the .packages file too since it is not used in compilation.
-    final Uri packageUri = _fileSystem.file(packagesPath).uri;
-    final DateTime updatedAt = _fileSystem.statSync(
-      packageUri.toFilePath(windows: _platform.isWindows)).modified;
+    final File packageFile = _fileSystem.file(packagesPath);
+    final Uri packageUri = packageFile.uri;
+    final DateTime updatedAt = packageFile.statSync().modified;
     if (updatedAt != null && updatedAt.isAfter(lastCompiled)) {
       invalidatedFiles.add(packageUri);
       packageConfig = await _createPackageConfig(packagesPath);

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

@@ -289,6 +289,22 @@ abstract class FlutterCommand extends Command<void> {
   /// This can be overridden by some of its subclasses.
   String get packagesPath => globalResults['packages'] as String;
 
+  /// The value of the `--filesystem-scheme` argument.
+  ///
+  /// This can be overridden by some of its subclasses.
+  String get fileSystemScheme =>
+    argParser.options.containsKey(FlutterOptions.kFileSystemScheme)
+          ? stringArg(FlutterOptions.kFileSystemScheme)
+          : null;
+
+  /// The values of the `--filesystem-root` argument.
+  ///
+  /// This can be overridden by some of its subclasses.
+  List<String> get fileSystemRoots =>
+    argParser.options.containsKey(FlutterOptions.kFileSystemRoot)
+          ? stringsArg(FlutterOptions.kFileSystemRoot)
+          : null;
+
   void usesPubOption({bool hide = false}) {
     argParser.addFlag('pub',
       defaultsTo: true,
@@ -1032,12 +1048,8 @@ abstract class FlutterCommand extends Command<void> {
       extraGenSnapshotOptions: extraGenSnapshotOptions?.isNotEmpty ?? false
         ? extraGenSnapshotOptions
         : null,
-      fileSystemRoots: argParser.options.containsKey(FlutterOptions.kFileSystemRoot)
-          ? stringsArg(FlutterOptions.kFileSystemRoot)
-          : null,
-      fileSystemScheme: argParser.options.containsKey(FlutterOptions.kFileSystemScheme)
-          ? stringArg(FlutterOptions.kFileSystemScheme)
-          : null,
+      fileSystemRoots: fileSystemRoots,
+      fileSystemScheme: fileSystemScheme,
       buildNumber: buildNumber,
       buildName: argParser.options.containsKey('build-name')
           ? stringArg('build-name')

packages/flutter_tools/test/general.shard/base/multi_root_file_system_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io' as io;
+
+import 'package:file/file.dart';
+import 'package:file/memory.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/multi_root_file_system.dart';
+
+import '../../src/common.dart';
+
+void setupFileSystem({
+  required MemoryFileSystem fs,
+  required List<String> directories,
+  required List<String> files,
+}) {
+  for (final String directory in directories) {
+    fs.directory(directory).createSync(recursive: true);
+  }
+
+  for (final String file in files) {
+    fs.file(file).writeAsStringSync('Content: $file');
+  }
+}
+
+void main() {
+  group('Posix style', () {
+    runTest(FileSystemStyle.posix);
+  });
+
+  group('Windows style', () {
+    runTest(FileSystemStyle.windows);
+  });
+}
+
+void runTest(FileSystemStyle style) {
+  final String sep = style == FileSystemStyle.windows ? r'\' : '/';
+  final String root = style == FileSystemStyle.windows ? r'C:\' : '/';
+  final String rootUri = style == FileSystemStyle.windows ? 'C:/' : '';
+
+  late MultiRootFileSystem fs;
+
+  setUp(() {
+    final MemoryFileSystem memory = MemoryFileSystem(style: style);
+    setupFileSystem(
+      fs: memory,
+      directories: <String>[
+        '${root}foo${sep}subdir',
+        '${root}bar',
+        '${root}bar${sep}bar_subdir',
+        '${root}other${sep}directory',
+      ],
+      files: <String>[
+        '${root}foo${sep}only_in_foo',
+        '${root}foo${sep}in_both',
+        '${root}foo${sep}subdir${sep}in_subdir',
+        '${root}bar${sep}only_in_bar',
+        '${root}bar${sep}in_both',
+        '${root}bar${sep}bar_subdir${sep}in_subdir',
+        '${root}other${sep}directory${sep}file',
+      ],
+    );
+
+    fs = MultiRootFileSystem(
+      delegate: memory,
+      scheme: 'scheme',
+      roots: <String>[
+        '${root}foo$sep',
+        '${root}bar',
+      ],
+    );
+  });
+
+  testWithoutContext('file inside root', () {
+    final File file = fs.file('${root}foo${sep}only_in_foo');
+    expect(file.readAsStringSync(), 'Content: ${root}foo${sep}only_in_foo');
+    expect(file.path, '${root}foo${sep}only_in_foo');
+    expect(file.uri, Uri.parse('scheme:///only_in_foo'));
+  });
+
+  testWithoutContext('file inside second root', () {
+    final File file = fs.file('${root}bar${sep}only_in_bar');
+    expect(file.readAsStringSync(), 'Content: ${root}bar${sep}only_in_bar');
+    expect(file.path, '${root}bar${sep}only_in_bar');
+    expect(file.uri, Uri.parse('scheme:///only_in_bar'));
+  });
+
+  testWithoutContext('file outside root', () {
+    final File file = fs.file('${root}other${sep}directory${sep}file');
+    expect(file.readAsStringSync(),
+        'Content: ${root}other${sep}directory${sep}file');
+    expect(file.path, '${root}other${sep}directory${sep}file');
+    expect(file.uri, Uri.parse('file:///${rootUri}other/directory/file'));
+  });
+
+  testWithoutContext('file with file system scheme', () {
+    final File file = fs.file('scheme:///only_in_foo');
+    expect(file.readAsStringSync(), 'Content: ${root}foo${sep}only_in_foo');
+    expect(file.path, '${root}foo${sep}only_in_foo');
+    expect(file.uri, Uri.parse('scheme:///only_in_foo'));
+  });
+
+  testWithoutContext('file with file system scheme URI', () {
+    final File file = fs.file(Uri.parse('scheme:///only_in_foo'));
+    expect(file.readAsStringSync(), 'Content: ${root}foo${sep}only_in_foo');
+    expect(file.path, '${root}foo${sep}only_in_foo');
+    expect(file.uri, Uri.parse('scheme:///only_in_foo'));
+  });
+
+  testWithoutContext('file in second root with file system scheme', () {
+    final File file = fs.file('scheme:///only_in_bar');
+    expect(file.readAsStringSync(), 'Content: ${root}bar${sep}only_in_bar');
+    expect(file.path, '${root}bar${sep}only_in_bar');
+    expect(file.uri, Uri.parse('scheme:///only_in_bar'));
+  });
+
+  testWithoutContext('file in second root with file system scheme URI', () {
+    final File file = fs.file(Uri.parse('scheme:///only_in_bar'));
+    expect(file.readAsStringSync(), 'Content: ${root}bar${sep}only_in_bar');
+    expect(file.path, '${root}bar${sep}only_in_bar');
+    expect(file.uri, Uri.parse('scheme:///only_in_bar'));
+  });
+
+  testWithoutContext('file in both roots', () {
+    final File file = fs.file(Uri.parse('scheme:///in_both'));
+    expect(file.readAsStringSync(), 'Content: ${root}foo${sep}in_both');
+    expect(file.path, '${root}foo${sep}in_both');
+    expect(file.uri, Uri.parse('scheme:///in_both'));
+  });
+
+  testWithoutContext('file with scheme in subdirectory', () {
+    final File file = fs.file(Uri.parse('scheme:///subdir/in_subdir'));
+    expect(file.readAsStringSync(),
+        'Content: ${root}foo${sep}subdir${sep}in_subdir');
+    expect(file.path, '${root}foo${sep}subdir${sep}in_subdir');
+    expect(file.uri, Uri.parse('scheme:///subdir/in_subdir'));
+  });
+
+  testWithoutContext('file in second root with scheme in subdirectory', () {
+    final File file = fs.file(Uri.parse('scheme:///bar_subdir/in_subdir'));
+    expect(file.readAsStringSync(),
+        'Content: ${root}bar${sep}bar_subdir${sep}in_subdir');
+    expect(file.path, '${root}bar${sep}bar_subdir${sep}in_subdir');
+    expect(file.uri, Uri.parse('scheme:///bar_subdir/in_subdir'));
+  });
+
+  testWithoutContext('non-existent file with scheme', () {
+    final File file = fs.file(Uri.parse('scheme:///not_exist'));
+    expect(file.uri, Uri.parse('scheme:///not_exist'));
+    expect(file.path, '${root}foo${sep}not_exist');
+  });
+
+  testWithoutContext('stat', () async {
+    expect((await fs.stat('${root}foo${sep}only_in_foo')).type, io.FileSystemEntityType.file);
+    expect((await fs.stat('scheme:///only_in_foo')).type, io.FileSystemEntityType.file);
+    expect(fs.statSync('${root}foo${sep}only_in_foo').type, io.FileSystemEntityType.file);
+    expect(fs.statSync('scheme:///only_in_foo').type, io.FileSystemEntityType.file);
+  });
+
+  testWithoutContext('type', () async {
+    expect(await fs.type('${root}foo${sep}only_in_foo'), io.FileSystemEntityType.file);
+    expect(await fs.type('scheme:///only_in_foo'), io.FileSystemEntityType.file);
+    expect(await fs.type('${root}foo${sep}subdir'), io.FileSystemEntityType.directory);
+    expect(await fs.type('scheme:///subdir'), io.FileSystemEntityType.directory);
+    expect(await fs.type('${root}foo${sep}not_found'), io.FileSystemEntityType.notFound);
+    expect(await fs.type('scheme:///not_found'), io.FileSystemEntityType.notFound);
+
+    expect(fs.typeSync('${root}foo${sep}only_in_foo'), io.FileSystemEntityType.file);
+    expect(fs.typeSync('scheme:///only_in_foo'), io.FileSystemEntityType.file);
+    expect(fs.typeSync('${root}foo${sep}subdir'), io.FileSystemEntityType.directory);
+    expect(fs.typeSync('scheme:///subdir'), io.FileSystemEntityType.directory);
+    expect(fs.typeSync('${root}foo${sep}not_found'), io.FileSystemEntityType.notFound);
+    expect(fs.typeSync('scheme:///not_found'), io.FileSystemEntityType.notFound);
+  });
+
+  testWithoutContext('identical', () async {
+    expect(await fs.identical('${root}foo${sep}in_both', '${root}foo${sep}in_both'), true);
+    expect(await fs.identical('${root}foo${sep}in_both', 'scheme:///in_both'), true);
+    expect(await fs.identical('${root}foo${sep}in_both', 'scheme:///in_both'), true);
+    expect(await fs.identical('${root}bar${sep}in_both', 'scheme:///in_both'), false);
+
+    expect(fs.identicalSync('${root}foo${sep}in_both', '${root}foo${sep}in_both'), true);
+    expect(fs.identicalSync('${root}foo${sep}in_both', 'scheme:///in_both'), true);
+    expect(fs.identicalSync('${root}foo${sep}in_both', 'scheme:///in_both'), true);
+    expect(fs.identicalSync('${root}bar${sep}in_both', 'scheme:///in_both'), false);
+  });
+}

packages/flutter_tools/test/general.shard/runner/flutter_command_test.dart

@@ -509,6 +509,18 @@ void main() {
       expect(buildInfo.packagesPath, 'foo');
     });
 
+    testUsingContext('use fileSystemScheme to generate BuildInfo', () async {
+      final DummyFlutterCommand flutterCommand = DummyFlutterCommand(fileSystemScheme: 'foo');
+      final BuildInfo buildInfo = await flutterCommand.getBuildInfo(forcedBuildMode: BuildMode.debug);
+      expect(buildInfo.fileSystemScheme, 'foo');
+    });
+
+    testUsingContext('use fileSystemRoots to generate BuildInfo', () async {
+      final DummyFlutterCommand flutterCommand = DummyFlutterCommand(fileSystemRoots: <String>['foo', 'bar']);
+      final BuildInfo buildInfo = await flutterCommand.getBuildInfo(forcedBuildMode: BuildMode.debug);
+      expect(buildInfo.fileSystemRoots, <String>['foo', 'bar']);
+    });
+
     testUsingContext('dds options', () async {
       final FakeDdsCommand ddsCommand = FakeDdsCommand();
       final CommandRunner<void> runner = createTestCommandRunner(ddsCommand);

packages/flutter_tools/test/general.shard/runner/utils.dart

@@ -16,6 +16,8 @@ class DummyFlutterCommand extends FlutterCommand {
     this.name = 'dummy',
     this.commandFunction,
     this.packagesPath,
+    this.fileSystemScheme,
+    this.fileSystemRoots,
   });
 
   final bool noUsagePath;
@@ -40,4 +42,10 @@ class DummyFlutterCommand extends FlutterCommand {
 
   @override
   final String packagesPath;
+
+  @override
+  final String fileSystemScheme;
+
+  @override
+  final List<String> fileSystemRoots;
 }

packages/flutter_tools/test/integration.shard/forbidden_imports_test.dart

@@ -66,6 +66,7 @@ void main() {
       fileSystem.path.join(flutterTools, 'lib', 'src', 'base', 'io.dart'),
       fileSystem.path.join(flutterTools, 'lib', 'src', 'base', 'platform.dart'),
       fileSystem.path.join(flutterTools, 'lib', 'src', 'base', 'error_handling_io.dart'),
+      fileSystem.path.join(flutterTools, 'lib', 'src', 'base', 'multi_root_file_system.dart'),
     ];
     bool _isNotAllowed(FileSystemEntity entity) => allowedPaths.every((String path) => path != entity.path);