From 63ff7a199b86fd483b6a30b7ff7457a96b7bf06c Mon Sep 17 00:00:00 2001
From: Gary Qian <garyq@google.com>
Date: Wed, 16 Mar 2022 11:10:22 -0700
Subject: [PATCH] MigrateConfig and migrate integration testing base (#99092)

---
 .../lib/src/commands/create.dart              |   8 +
 .../lib/src/commands/create_base.dart         |  78 ++++-
 .../lib/src/flutter_project_metadata.dart     | 328 +++++++++++++++---
 packages/flutter_tools/lib/src/project.dart   |  55 ++-
 .../flutter_tools/lib/src/xcode_project.dart  |   6 +
 .../templates/app_shared/.gitignore.tmpl      |   1 +
 .../templates/app_shared/.metadata.tmpl       |  10 -
 .../templates/module/common/.gitignore.tmpl   |   2 +
 .../templates/package/.gitignore.tmpl         |   1 +
 .../templates/plugin_shared/.gitignore.tmpl   |   1 +
 .../hermetic/create_usage_test.dart           |  10 +-
 .../flutter_project_metadata_test.dart        | 102 +++++-
 .../migrate_config_test.dart                  | 231 ++++++++++++
 .../vanilla_app_1_22_6_stable.ensure          |   1 +
 .../test_data/migrate_project.dart            | 237 +++++++++++++
 .../test/integration.shard/test_utils.dart    |   2 +-
 16 files changed, 982 insertions(+), 91 deletions(-)
 delete mode 100644 packages/flutter_tools/templates/app_shared/.metadata.tmpl
 create mode 100644 packages/flutter_tools/test/integration.shard/migrate_config_test.dart
 create mode 100644 packages/flutter_tools/test/integration.shard/test_data/full_apps/vanilla_app_1_22_6_stable.ensure
 create mode 100644 packages/flutter_tools/test/integration.shard/test_data/migrate_project.dart

diff --git a/packages/flutter_tools/lib/src/commands/create.dart b/packages/flutter_tools/lib/src/commands/create.dart
index 81731938ff..f0c7263297 100644
--- a/packages/flutter_tools/lib/src/commands/create.dart
+++ b/packages/flutter_tools/lib/src/commands/create.dart
@@ -320,6 +320,7 @@ class CreateCommand extends CreateBase {
           templateContext,
           overwrite: overwrite,
           printStatusWhenWriting: !creatingNewProject,
+          projectType: template,
         );
         break;
       case FlutterProjectType.skeleton:
@@ -329,6 +330,7 @@ class CreateCommand extends CreateBase {
           templateContext,
           overwrite: overwrite,
           printStatusWhenWriting: !creatingNewProject,
+          generateMetadata: false,
         );
         break;
       case FlutterProjectType.module:
@@ -353,6 +355,7 @@ class CreateCommand extends CreateBase {
           templateContext,
           overwrite: overwrite,
           printStatusWhenWriting: !creatingNewProject,
+          projectType: template,
         );
         break;
       case FlutterProjectType.ffiPlugin:
@@ -361,6 +364,7 @@ class CreateCommand extends CreateBase {
           templateContext,
           overwrite: overwrite,
           printStatusWhenWriting: !creatingNewProject,
+          projectType: template,
         );
         break;
     }
@@ -495,6 +499,7 @@ Your $application code is in $relativeAppMain.
     Map<String, dynamic> templateContext, {
     bool overwrite = false,
     bool printStatusWhenWriting = true,
+    FlutterProjectType projectType,
   }) async {
     // Plugins only add a platform if it was requested explicitly by the user.
     if (!argResults.wasParsed('platforms')) {
@@ -561,6 +566,7 @@ Your $application code is in $relativeAppMain.
       overwrite: overwrite,
       pluginExampleApp: true,
       printStatusWhenWriting: printStatusWhenWriting,
+      projectType: projectType,
     );
     return generatedCount;
   }
@@ -570,6 +576,7 @@ Your $application code is in $relativeAppMain.
     Map<String, dynamic> templateContext, {
     bool overwrite = false,
     bool printStatusWhenWriting = true,
+    FlutterProjectType projectType,
   }) async {
     // Plugins only add a platform if it was requested explicitly by the user.
     if (!argResults.wasParsed('platforms')) {
@@ -637,6 +644,7 @@ Your $application code is in $relativeAppMain.
       overwrite: overwrite,
       pluginExampleApp: true,
       printStatusWhenWriting: printStatusWhenWriting,
+      projectType: projectType,
     );
     return generatedCount;
   }
diff --git a/packages/flutter_tools/lib/src/commands/create_base.dart b/packages/flutter_tools/lib/src/commands/create_base.dart
index dfc2331f16..85109c39a1 100644
--- a/packages/flutter_tools/lib/src/commands/create_base.dart
+++ b/packages/flutter_tools/lib/src/commands/create_base.dart
@@ -134,6 +134,13 @@ abstract class CreateBase extends FlutterCommand {
           'This is only intended to enable testing of the tool itself.',
       hide: !verboseHelp,
     );
+    argParser.addOption(
+      'initial-create-revision',
+      defaultsTo: null,
+      help: 'The Flutter SDK git commit hash to store in .migrate_config. This parameter is used by the tool '
+            'internally and should generally not be used manually.',
+      hide: !verboseHelp,
+    );
   }
 
   /// The output directory of the command.
@@ -488,6 +495,8 @@ abstract class CreateBase extends FlutterCommand {
     bool overwrite = false,
     bool pluginExampleApp = false,
     bool printStatusWhenWriting = true,
+    bool generateMetadata = true,
+    FlutterProjectType projectType,
   }) async {
     int generatedCount = 0;
     generatedCount += await renderMerged(
@@ -502,6 +511,14 @@ abstract class CreateBase extends FlutterCommand {
       generatedCount += _injectGradleWrapper(project);
     }
 
+    final bool androidPlatform = templateContext['android'] as bool ?? false;
+    final bool iosPlatform = templateContext['ios'] as bool ?? false;
+    final bool linuxPlatform = templateContext['linux'] as bool ?? false;
+    final bool macOSPlatform = templateContext['macos'] as bool ?? false;
+    final bool windowsPlatform = templateContext['windows'] as bool ?? false;
+    final bool webPlatform = templateContext['web'] as bool ?? false;
+    final bool winUwpPlatform = templateContext['winuwp'] as bool ?? false;
+
     if (boolArg('pub')) {
       final Environment environment = Environment(
         artifacts: globals.artifacts,
@@ -534,18 +551,63 @@ abstract class CreateBase extends FlutterCommand {
       );
 
       await project.ensureReadyForPlatformSpecificTooling(
-        androidPlatform: templateContext['android'] as bool ?? false,
-        iosPlatform: templateContext['ios'] as bool ?? false,
-        linuxPlatform: templateContext['linux'] as bool ?? false,
-        macOSPlatform: templateContext['macos'] as bool ?? false,
-        windowsPlatform: templateContext['windows'] as bool ?? false,
-        webPlatform: templateContext['web'] as bool ?? false,
-        winUwpPlatform: templateContext['winuwp'] as bool ?? false,
+        androidPlatform: androidPlatform,
+        iosPlatform: iosPlatform,
+        linuxPlatform: linuxPlatform,
+        macOSPlatform: macOSPlatform,
+        windowsPlatform: windowsPlatform,
+        webPlatform: webPlatform,
+        winUwpPlatform: winUwpPlatform,
       );
     }
-    if (templateContext['android'] == true) {
+    final List<SupportedPlatform> platformsForMigrateConfig = <SupportedPlatform>[SupportedPlatform.root];
+    if (androidPlatform) {
       gradle.updateLocalProperties(project: project, requireAndroidSdk: false);
+      platformsForMigrateConfig.add(SupportedPlatform.android);
     }
+    if (iosPlatform) {
+      platformsForMigrateConfig.add(SupportedPlatform.ios);
+    }
+    if (linuxPlatform) {
+      platformsForMigrateConfig.add(SupportedPlatform.linux);
+    }
+    if (macOSPlatform) {
+      platformsForMigrateConfig.add(SupportedPlatform.macos);
+    }
+    if (webPlatform) {
+      platformsForMigrateConfig.add(SupportedPlatform.web);
+    }
+    if (windowsPlatform) {
+      platformsForMigrateConfig.add(SupportedPlatform.windows);
+    }
+    if (winUwpPlatform) {
+      platformsForMigrateConfig.add(SupportedPlatform.windowsuwp);
+    }
+    if (templateContext['fuchsia'] == true) {
+      platformsForMigrateConfig.add(SupportedPlatform.fuchsia);
+    }
+    if (generateMetadata) {
+      final File metadataFile = globals.fs
+          .file(globals.fs.path.join(projectDir.absolute.path, '.metadata'));
+      final FlutterProjectMetadata metadata = FlutterProjectMetadata.explicit(
+        file: metadataFile,
+        versionRevision: globals.flutterVersion.frameworkRevision,
+        versionChannel: globals.flutterVersion.channel,
+        projectType: projectType,
+        migrateConfig: MigrateConfig(),
+        logger: globals.logger);
+      metadata.populate(
+        platforms: platformsForMigrateConfig,
+        projectDirectory: directory,
+        create: true,
+        update: false,
+        currentRevision: stringArg('initial-create-revision') ?? globals.flutterVersion.frameworkRevision,
+        createRevision: globals.flutterVersion.frameworkRevision,
+        logger: globals.logger,
+      );
+      metadata.writeFile();
+    }
+
     return generatedCount;
   }
 
diff --git a/packages/flutter_tools/lib/src/flutter_project_metadata.dart b/packages/flutter_tools/lib/src/flutter_project_metadata.dart
index da2800fbf0..e2fcf2e901 100644
--- a/packages/flutter_tools/lib/src/flutter_project_metadata.dart
+++ b/packages/flutter_tools/lib/src/flutter_project_metadata.dart
@@ -7,6 +7,8 @@ import 'package:yaml/yaml.dart';
 import 'base/file_system.dart';
 import 'base/logger.dart';
 import 'base/utils.dart';
+import 'project.dart';
+import 'version.dart';
 
 enum FlutterProjectType {
   /// This is the default project with the user-managed host code.
@@ -27,7 +29,10 @@ enum FlutterProjectType {
   ffiPlugin,
 }
 
-String flutterProjectTypeToString(FlutterProjectType type) {
+String flutterProjectTypeToString(FlutterProjectType? type) {
+  if (type == null) {
+    return '';
+  }
   if (type == FlutterProjectType.ffiPlugin) {
     return 'plugin_ffi';
   }
@@ -45,67 +50,286 @@ FlutterProjectType? stringToProjectType(String value) {
   return result;
 }
 
+  /// Verifies the expected yaml keys are present in the file.
+  bool _validateMetadataMap(Object? yamlRoot, Map<String, Type> validations, Logger logger) {
+    if (yamlRoot != null && yamlRoot is! YamlMap) {
+      return false;
+    }
+    final YamlMap map = yamlRoot! as YamlMap;
+    bool isValid = true;
+    for (final MapEntry<String, Object> entry in validations.entries) {
+      if (!map.keys.contains(entry.key)) {
+        isValid = false;
+        logger.printTrace('The key `${entry.key}` was not found');
+        break;
+      }
+      if (map[entry.key] != null && (map[entry.key] as Object).runtimeType != entry.value) {
+        isValid = false;
+        logger.printTrace('The value of key `${entry.key}` in .metadata was expected to be ${entry.value} but was ${(map[entry.key] as Object).runtimeType}');
+        break;
+      }
+    }
+    return isValid;
+  }
+
 /// A wrapper around the `.metadata` file.
 class FlutterProjectMetadata {
-  FlutterProjectMetadata(
-    File metadataFile,
-    Logger logger,
-    )  : _metadataFile = metadataFile,
-      _logger = logger;
+  /// Creates a MigrateConfig by parsing an existing .migrate_config yaml file.
+  FlutterProjectMetadata(File file, Logger logger) : _metadataFile = file,
+                                                     _logger = logger,
+                                                     migrateConfig = MigrateConfig() {
+    if (!_metadataFile.existsSync()) {
+      _logger.printTrace('No .metadata file found at ${_metadataFile.path}.');
+      // Create a default empty metadata.
+      return;
+    }
+    Object? yamlRoot;
+    try {
+      yamlRoot = loadYaml(_metadataFile.readAsStringSync());
+    } on YamlException {
+      // Handled in _validate below.
+    }
+    if (yamlRoot == null || yamlRoot is! YamlMap) {
+      _logger.printTrace('.metadata file at ${_metadataFile.path} was empty or malformed.');
+      return;
+    }
+    final YamlMap map = yamlRoot;
+    if (_validateMetadataMap(yamlRoot, <String, Type>{'version': YamlMap}, _logger)) {
+      final Object? versionYaml = map['version'];
+      if (_validateMetadataMap(versionYaml, <String, Type>{
+            'revision': String,
+            'channel': String,
+          }, _logger)) {
+        final YamlMap versionYamlMap = versionYaml! as YamlMap;
+        _versionRevision = versionYamlMap['revision'] as String?;
+        _versionChannel = versionYamlMap['channel'] as String?;
+      }
+    }
+    if (_validateMetadataMap(yamlRoot, <String, Type>{'project_type': String}, _logger)) {
+      _projectType = stringToProjectType(map['project_type'] as String);
+    }
+    final Object? migrationYaml = map['migration'];
+    if (migrationYaml != null && migrationYaml is YamlMap) {
+      migrateConfig.parseYaml(map['migration'] as YamlMap, _logger);
+    }
+  }
+
+  /// Creates a MigrateConfig by explicitly providing all values.
+  FlutterProjectMetadata.explicit({
+    required File file,
+    required String? versionRevision,
+    required String? versionChannel,
+    required FlutterProjectType? projectType,
+    required this.migrateConfig,
+    required Logger logger,
+  }) : _logger = logger,
+       _versionChannel = versionChannel,
+       _versionRevision = versionRevision,
+       _projectType = projectType,
+       _metadataFile = file;
+
+  /// The name of the config file.
+  static const String kFileName = '.metadata';
+
+  String? _versionRevision;
+  String? get versionRevision => _versionRevision;
+
+  String? _versionChannel;
+  String? get versionChannel => _versionChannel;
+
+  FlutterProjectType? _projectType;
+  FlutterProjectType? get projectType => _projectType;
+
+  /// Metadata and configuration for the migrate command.
+  MigrateConfig migrateConfig;
 
-  final File _metadataFile;
   final Logger _logger;
 
-  String? get versionChannel => _versionValue('channel');
-  String? get versionRevision => _versionValue('revision');
+  final File _metadataFile;
 
-  FlutterProjectType? get projectType {
-    final dynamic projectTypeYaml = _metadataValue('project_type');
-    if (projectTypeYaml is String) {
-      return stringToProjectType(projectTypeYaml);
-    } else {
-      _logger.printTrace('.metadata project_type version is malformed.');
-      return null;
-    }
+  /// Writes the .migrate_config file in the provided project directory's platform subdirectory.
+  ///
+  /// We write the file manually instead of with a template because this
+  /// needs to be able to write the .migrate_config file into legacy apps.
+  void writeFile({File? outputFile}) {
+    outputFile = outputFile ?? _metadataFile;
+    outputFile
+      ..createSync(recursive: true)
+      ..writeAsStringSync('''
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: $_versionRevision
+  channel: $_versionChannel
+
+project_type: ${flutterProjectTypeToString(projectType)}
+${migrateConfig.getOutputFileString()}''',
+    flush: true);
   }
 
-  YamlMap? _versionYaml;
-  String? _versionValue(String key) {
-    if (_versionYaml == null) {
-      final dynamic versionYaml = _metadataValue('version');
-      if (versionYaml is YamlMap) {
-        _versionYaml = versionYaml;
-      } else {
-        _logger.printTrace('.metadata version is malformed.');
-        return null;
-      }
-    }
-    if (_versionYaml != null && _versionYaml!.containsKey(key) && _versionYaml![key] is String) {
-      return _versionYaml![key] as String;
-    }
-    return null;
+  void populate({
+    List<SupportedPlatform>? platforms,
+    Directory? projectDirectory,
+    String? currentRevision,
+    String? createRevision,
+    bool create = true,
+    bool update = true,
+    required Logger logger,
+  }) {
+    migrateConfig.populate(
+      platforms: platforms,
+      projectDirectory: projectDirectory,
+      currentRevision: currentRevision,
+      createRevision: createRevision,
+      create: create,
+      update: update,
+      logger: logger,
+    );
   }
 
-  YamlMap? _metadataYaml;
-  dynamic _metadataValue(String key) {
-    if (_metadataYaml == null) {
-      if (!_metadataFile.existsSync()) {
-        return null;
-      }
-      dynamic metadataYaml;
-      try {
-        metadataYaml = loadYaml(_metadataFile.readAsStringSync());
-      } on YamlException {
-        // Handled in return below.
-      }
-      if (metadataYaml is YamlMap) {
-        _metadataYaml = metadataYaml;
-      } else {
-        _logger.printTrace('.metadata is malformed.');
-        return null;
-      }
+  /// Finds the fallback revision to use when no base revision is found in the migrate config.
+  String getFallbackBaseRevision(Logger logger, FlutterVersion flutterVersion) {
+    // Use the .metadata file if it exists.
+    if (versionRevision != null) {
+      return versionRevision!;
     }
-
-    return _metadataYaml![key];
+    return flutterVersion.frameworkRevision;
   }
 }
+
+/// Represents the migrate command metadata section of a .metadata file.
+///
+/// This file tracks the flutter sdk git hashes of the last successful migration ('base') and
+/// the version the project was created with.
+///
+/// Each platform tracks a different set of revisions because flutter create can be
+/// used to add support for new platforms, so the base and create revision may not always be the same.
+class MigrateConfig {
+  MigrateConfig({
+    Map<SupportedPlatform, MigratePlatformConfig>? platformConfigs,
+    this.unmanagedFiles = _kDefaultUnmanagedFiles
+  }) : platformConfigs = platformConfigs ?? <SupportedPlatform, MigratePlatformConfig>{};
+
+  /// A mapping of the files that are unmanaged by defult for each platform.
+  static const List<String> _kDefaultUnmanagedFiles = <String>[
+    'lib/main.dart',
+    'ios/Runner.xcodeproj/project.pbxproj',
+  ];
+
+  /// The metadata for each platform supported by the project.
+  final Map<SupportedPlatform, MigratePlatformConfig> platformConfigs;
+
+  /// A list of paths relative to this file the migrate tool should ignore.
+  ///
+  /// These files are typically user-owned files that should not be changed.
+  List<String> unmanagedFiles;
+
+  bool get isEmpty => platformConfigs.isEmpty && (unmanagedFiles.isEmpty || unmanagedFiles == _kDefaultUnmanagedFiles);
+
+  /// Parses the project for all supported platforms and populates the [MigrateConfig]
+  /// to reflect the project.
+  void populate({
+    List<SupportedPlatform>? platforms,
+    Directory? projectDirectory,
+    String? currentRevision,
+    String? createRevision,
+    bool create = true,
+    bool update = true,
+    required Logger logger,
+  }) {
+    final FlutterProject flutterProject = projectDirectory == null ? FlutterProject.current() : FlutterProject.fromDirectory(projectDirectory);
+    platforms ??= flutterProject.getSupportedPlatforms(includeRoot: true);
+
+    for (final SupportedPlatform platform in platforms) {
+      if (platformConfigs.containsKey(platform)) {
+        if (update) {
+          platformConfigs[platform]!.baseRevision = currentRevision;
+        }
+      } else {
+        if (create) {
+          platformConfigs[platform] = MigratePlatformConfig(createRevision: createRevision, baseRevision: currentRevision);
+        }
+      }
+    }
+  }
+
+  /// Returns the string that should be written to the .metadata file.
+  String getOutputFileString() {
+    String unmanagedFilesString = '';
+    for (final String path in unmanagedFiles) {
+      unmanagedFilesString += "\n    - '$path'";
+    }
+
+    String platformsString = '';
+    for (final MapEntry<SupportedPlatform, MigratePlatformConfig> entry in platformConfigs.entries) {
+      platformsString += '\n    - platform: ${entry.key.toString().split('.').last}\n      create_revision: ${entry.value.createRevision == null ? 'null' : "${entry.value.createRevision}"}\n      base_revision: ${entry.value.baseRevision == null ? 'null' : "${entry.value.baseRevision}"}';
+    }
+
+    return isEmpty ? '' : '''
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:$platformsString
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:$unmanagedFilesString
+''';
+  }
+
+  /// Parses and validates the `migration` section of the .metadata file.
+  void parseYaml(YamlMap map, Logger logger) {
+    final Object? platformsYaml = map['platforms'];
+    if (_validateMetadataMap(map, <String, Type>{'platforms': YamlList}, logger)) {
+      if (platformsYaml is YamlList && platformsYaml.isNotEmpty) {
+        for (final Object? platform in platformsYaml) {
+          if (_validateMetadataMap(platform, <String, Type>{
+                'platform': String,
+                'create_revision': String,
+                'base_revision': String,
+              }, logger)) {
+            final YamlMap platformYamlMap = platform! as YamlMap;
+            final SupportedPlatform platformString = SupportedPlatform.values.firstWhere(
+              (SupportedPlatform val) => val.toString() == 'SupportedPlatform.${platformYamlMap['platform'] as String}'
+            );
+            platformConfigs[platformString] = MigratePlatformConfig(
+              createRevision: platformYamlMap['create_revision'] as String?,
+              baseRevision: platformYamlMap['base_revision'] as String?,
+            );
+          } else {
+            // malformed platform entry
+            continue;
+          }
+        }
+      }
+    }
+    if (_validateMetadataMap(map, <String, Type>{'unmanaged_files': YamlList}, logger)) {
+      final Object? unmanagedFilesYaml = map['unmanaged_files'];
+      if (unmanagedFilesYaml is YamlList && unmanagedFilesYaml.isNotEmpty) {
+        unmanagedFiles = List<String>.from(unmanagedFilesYaml.value.cast<String>());
+      }
+    }
+  }
+}
+
+/// Holds the revisions for a single platform for use by the flutter migrate command.
+class MigratePlatformConfig {
+  MigratePlatformConfig({this.createRevision, this.baseRevision});
+
+  /// The Flutter SDK revision this platform was created by.
+  ///
+  /// Null if the initial create git revision is unknown.
+  final String? createRevision;
+
+  /// The Flutter SDK revision this platform was last migrated by.
+  ///
+  /// Null if the project was never migrated or the revision is unknown.
+  String? baseRevision;
+}
diff --git a/packages/flutter_tools/lib/src/project.dart b/packages/flutter_tools/lib/src/project.dart
index 52276c4ace..d56afe6270 100644
--- a/packages/flutter_tools/lib/src/project.dart
+++ b/packages/flutter_tools/lib/src/project.dart
@@ -27,6 +27,19 @@ import 'xcode_project.dart';
 export 'cmake_project.dart';
 export 'xcode_project.dart';
 
+/// Emum for each officially supported platform.
+enum SupportedPlatform {
+  android,
+  ios,
+  linux,
+  macos,
+  web,
+  windows,
+  windowsuwp,
+  fuchsia,
+  root, // Special platform to represent the root project directory
+}
+
 class FlutterProjectFactory {
   FlutterProjectFactory({
     required Logger logger,
@@ -244,6 +257,36 @@ class FlutterProject {
   /// True if this project has an example application.
   bool get hasExampleApp => _exampleDirectory(directory).existsSync();
 
+  /// Returns a list of platform names that are supported by the project.
+  List<SupportedPlatform> getSupportedPlatforms({bool includeRoot = false}) {
+    final List<SupportedPlatform> platforms = includeRoot ? <SupportedPlatform>[SupportedPlatform.root] : <SupportedPlatform>[];
+    if (android.existsSync()) {
+      platforms.add(SupportedPlatform.android);
+    }
+    if (ios.exists) {
+      platforms.add(SupportedPlatform.ios);
+    }
+    if (web.existsSync()) {
+      platforms.add(SupportedPlatform.web);
+    }
+    if (macos.existsSync()) {
+      platforms.add(SupportedPlatform.macos);
+    }
+    if (linux.existsSync()) {
+      platforms.add(SupportedPlatform.linux);
+    }
+    if (windows.existsSync()) {
+      platforms.add(SupportedPlatform.windows);
+    }
+    if (windowsUwp.existsSync()) {
+      platforms.add(SupportedPlatform.windowsuwp);
+    }
+    if (fuchsia.existsSync()) {
+      platforms.add(SupportedPlatform.fuchsia);
+    }
+    return platforms;
+  }
+
   /// The directory that will contain the example if an example exists.
   static Directory _exampleDirectory(Directory directory) => directory.childDirectory('example');
 
@@ -555,12 +598,10 @@ class AndroidProject extends FlutterProjectPlatform {
     if (deprecationBehavior == DeprecationBehavior.none) {
       return;
     }
-
     final AndroidEmbeddingVersionResult result = computeEmbeddingVersion();
     if (result.version != AndroidEmbeddingVersion.v1) {
       return;
     }
-
     globals.printStatus(
 '''
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
@@ -584,11 +625,11 @@ The detected reason was:
     if (deprecationBehavior == DeprecationBehavior.ignore) {
       BuildEvent('deprecated-v1-android-embedding-ignored', type: 'gradle', flutterUsage: globals.flutterUsage).send();
     } else { // DeprecationBehavior.exit
-        BuildEvent('deprecated-v1-android-embedding-failed', type: 'gradle', flutterUsage: globals.flutterUsage).send();
-        throwToolExit(
-          'Build failed due to use of deprecated Android v1 embedding.',
-          exitCode: 1,
-        );
+      BuildEvent('deprecated-v1-android-embedding-failed', type: 'gradle', flutterUsage: globals.flutterUsage).send();
+      throwToolExit(
+        'Build failed due to use of deprecated Android v1 embedding.',
+        exitCode: 1,
+      );
     }
   }
 
diff --git a/packages/flutter_tools/lib/src/xcode_project.dart b/packages/flutter_tools/lib/src/xcode_project.dart
index e6ef98f702..6faec24d27 100644
--- a/packages/flutter_tools/lib/src/xcode_project.dart
+++ b/packages/flutter_tools/lib/src/xcode_project.dart
@@ -134,6 +134,12 @@ class IosProject extends XcodeBasedProject {
 
   Directory get symlinks => _flutterLibRoot.childDirectory('.symlinks');
 
+  /// True, if the app project is using swift.
+  bool get isSwift {
+    final File appDelegateSwift = _editableDirectory.childDirectory('Runner').childFile('AppDelegate.swift');
+    return appDelegateSwift.existsSync();
+  }
+
   /// Do all plugins support arm64 simulators to run natively on an ARM Mac?
   Future<bool> pluginsSupportArmSimulator() async {
     final Directory podXcodeProject = hostAppRoot
diff --git a/packages/flutter_tools/templates/app_shared/.gitignore.tmpl b/packages/flutter_tools/templates/app_shared/.gitignore.tmpl
index 0fa6b675c0..a8e938c083 100644
--- a/packages/flutter_tools/templates/app_shared/.gitignore.tmpl
+++ b/packages/flutter_tools/templates/app_shared/.gitignore.tmpl
@@ -8,6 +8,7 @@
 .buildlog/
 .history
 .svn/
+migrate_working_dir/
 
 # IntelliJ related
 *.iml
diff --git a/packages/flutter_tools/templates/app_shared/.metadata.tmpl b/packages/flutter_tools/templates/app_shared/.metadata.tmpl
deleted file mode 100644
index 98005dbbcb..0000000000
--- a/packages/flutter_tools/templates/app_shared/.metadata.tmpl
+++ /dev/null
@@ -1,10 +0,0 @@
-# This file tracks properties of this Flutter project.
-# Used by Flutter tool to assess capabilities and perform upgrades etc.
-#
-# This file should be version controlled and should not be manually edited.
-
-version:
-  revision: {{flutterRevision}}
-  channel: {{flutterChannel}}
-
-project_type: app
diff --git a/packages/flutter_tools/templates/module/common/.gitignore.tmpl b/packages/flutter_tools/templates/module/common/.gitignore.tmpl
index ff612b3be4..9141595fb9 100644
--- a/packages/flutter_tools/templates/module/common/.gitignore.tmpl
+++ b/packages/flutter_tools/templates/module/common/.gitignore.tmpl
@@ -9,6 +9,8 @@
 .sconsign.dblite
 .svn/
 
+migrate_working_dir/
+
 *.swp
 profile
 
diff --git a/packages/flutter_tools/templates/package/.gitignore.tmpl b/packages/flutter_tools/templates/package/.gitignore.tmpl
index 9be145fde9..96486fd930 100644
--- a/packages/flutter_tools/templates/package/.gitignore.tmpl
+++ b/packages/flutter_tools/templates/package/.gitignore.tmpl
@@ -8,6 +8,7 @@
 .buildlog/
 .history
 .svn/
+migrate_working_dir/
 
 # IntelliJ related
 *.iml
diff --git a/packages/flutter_tools/templates/plugin_shared/.gitignore.tmpl b/packages/flutter_tools/templates/plugin_shared/.gitignore.tmpl
index 9be145fde9..96486fd930 100644
--- a/packages/flutter_tools/templates/plugin_shared/.gitignore.tmpl
+++ b/packages/flutter_tools/templates/plugin_shared/.gitignore.tmpl
@@ -8,6 +8,7 @@
 .buildlog/
 .history
 .svn/
+migrate_working_dir/
 
 # IntelliJ related
 *.iml
diff --git a/packages/flutter_tools/test/commands.shard/hermetic/create_usage_test.dart b/packages/flutter_tools/test/commands.shard/hermetic/create_usage_test.dart
index bb283a3198..b4a889c937 100644
--- a/packages/flutter_tools/test/commands.shard/hermetic/create_usage_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/create_usage_test.dart
@@ -88,19 +88,19 @@ void main() {
       await runner.run(<String>['create', '--no-pub', '--template=module', 'testy']);
       expect((await command.usageValues).commandCreateProjectType, 'module');
 
-      await runner.run(<String>['create', '--no-pub', '--template=app', 'testy']);
+      await runner.run(<String>['create', '--no-pub', '--template=app', 'testy1']);
       expect((await command.usageValues).commandCreateProjectType, 'app');
 
-      await runner.run(<String>['create', '--no-pub', '--template=skeleton', 'testy']);
+      await runner.run(<String>['create', '--no-pub', '--template=skeleton', 'testy2']);
       expect((await command.usageValues).commandCreateProjectType, 'skeleton');
 
-      await runner.run(<String>['create', '--no-pub', '--template=package', 'testy']);
+      await runner.run(<String>['create', '--no-pub', '--template=package', 'testy3']);
       expect((await command.usageValues).commandCreateProjectType, 'package');
 
-      await runner.run(<String>['create', '--no-pub', '--template=plugin', 'testy']);
+      await runner.run(<String>['create', '--no-pub', '--template=plugin', 'testy4']);
       expect((await command.usageValues).commandCreateProjectType, 'plugin');
 
-      await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', 'testy']);
+      await runner.run(<String>['create', '--no-pub', '--template=plugin_ffi', 'testy5']);
       expect((await command.usageValues).commandCreateProjectType, 'plugin_ffi');
     }));
 
diff --git a/packages/flutter_tools/test/general.shard/flutter_project_metadata_test.dart b/packages/flutter_tools/test/general.shard/flutter_project_metadata_test.dart
index 79a2f2d6a6..b5bfdd0c67 100644
--- a/packages/flutter_tools/test/general.shard/flutter_project_metadata_test.dart
+++ b/packages/flutter_tools/test/general.shard/flutter_project_metadata_test.dart
@@ -6,6 +6,7 @@ import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/flutter_project_metadata.dart';
+import 'package:flutter_tools/src/project.dart';
 
 import '../src/common.dart';
 
@@ -26,8 +27,7 @@ void main() {
     expect(projectMetadata.versionChannel, isNull);
     expect(projectMetadata.versionRevision, isNull);
 
-    expect(logger.traceText, contains('.metadata project_type version is malformed.'));
-    expect(logger.traceText, contains('.metadata version is malformed.'));
+    expect(logger.traceText, contains('No .metadata file found at .metadata'));
   });
 
   testWithoutContext('project metadata fields are empty when file is empty', () {
@@ -37,8 +37,7 @@ void main() {
     expect(projectMetadata.versionChannel, isNull);
     expect(projectMetadata.versionRevision, isNull);
 
-    expect(logger.traceText, contains('.metadata project_type version is malformed.'));
-    expect(logger.traceText, contains('.metadata version is malformed.'));
+    expect(logger.traceText, contains('.metadata file at .metadata was empty or malformed.'));
   });
 
   testWithoutContext('project metadata fields are empty when file is not valid yaml', () {
@@ -48,8 +47,7 @@ void main() {
     expect(projectMetadata.versionChannel, isNull);
     expect(projectMetadata.versionRevision, isNull);
 
-    expect(logger.traceText, contains('.metadata project_type version is malformed.'));
-    expect(logger.traceText, contains('.metadata version is malformed.'));
+    expect(logger.traceText, contains('.metadata file at .metadata was empty or malformed.'));
   });
 
   testWithoutContext('projectType is populated when version is malformed', () {
@@ -64,7 +62,7 @@ project_type: plugin
     expect(projectMetadata.versionChannel, isNull);
     expect(projectMetadata.versionRevision, isNull);
 
-    expect(logger.traceText, contains('.metadata version is malformed.'));
+    expect(logger.traceText, contains('The value of key `version` in .metadata was expected to be YamlMap but was String'));
   });
 
   testWithoutContext('version is populated when projectType is malformed', () {
@@ -81,6 +79,94 @@ project_type: {}
     expect(projectMetadata.versionChannel, 'stable');
     expect(projectMetadata.versionRevision, 'b59b226a49391949247e3d6122e34bb001049ae4');
 
-    expect(logger.traceText, contains('.metadata project_type version is malformed.'));
+    expect(logger.traceText, contains('The value of key `project_type` in .metadata was expected to be String but was YamlMap'));
+  });
+
+  testWithoutContext('migrate config is populated when version is malformed', () {
+    metadataFile
+      ..createSync()
+      ..writeAsStringSync('''
+version: STRING INSTEAD OF MAP
+project_type: {}
+
+migration:
+  platforms:
+    - platform: root
+      create_revision: abcdefg
+      base_revision: baserevision
+
+  unmanaged_files:
+    - 'file1'
+      ''');
+    final FlutterProjectMetadata projectMetadata = FlutterProjectMetadata(metadataFile, logger);
+    expect(projectMetadata.projectType, isNull);
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.root]?.createRevision, 'abcdefg');
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.root]?.baseRevision, 'baserevision');
+    expect(projectMetadata.migrateConfig.unmanagedFiles[0], 'file1');
+
+    expect(logger.traceText, contains('The value of key `version` in .metadata was expected to be YamlMap but was String'));
+    expect(logger.traceText, contains('The value of key `project_type` in .metadata was expected to be String but was YamlMap'));
+  });
+
+  testWithoutContext('migrate config is populated when unmanaged_files is malformed', () {
+    metadataFile
+      ..createSync()
+      ..writeAsStringSync('''
+version:
+  revision: b59b226a49391949247e3d6122e34bb001049ae4
+  channel: stable
+project_type: app
+
+migration:
+  platforms:
+    - platform: root
+      create_revision: abcdefg
+      base_revision: baserevision
+
+  unmanaged_files: {}
+      ''');
+    final FlutterProjectMetadata projectMetadata = FlutterProjectMetadata(metadataFile, logger);
+    expect(projectMetadata.projectType, FlutterProjectType.app);
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.root]?.createRevision, 'abcdefg');
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.root]?.baseRevision, 'baserevision');
+    // Tool uses default unamanged files list when malformed.
+    expect(projectMetadata.migrateConfig.unmanagedFiles[0], 'lib/main.dart');
+
+    expect(logger.traceText, contains('The value of key `unmanaged_files` in .metadata was expected to be YamlList but was YamlMap'));
+  });
+
+  testWithoutContext('platforms is populated with a malformed entry', () {
+    metadataFile
+      ..createSync()
+      ..writeAsStringSync('''
+version:
+  revision: b59b226a49391949247e3d6122e34bb001049ae4
+  channel: stable
+project_type: app
+
+migration:
+  platforms:
+    - platform: root
+      create_revision: abcdefg
+      base_revision: baserevision
+    - platform: android
+      base_revision: baserevision
+    - platform: ios
+      create_revision: abcdefg
+      base_revision: baserevision
+
+  unmanaged_files:
+    - 'file1'
+      ''');
+    final FlutterProjectMetadata projectMetadata = FlutterProjectMetadata(metadataFile, logger);
+    expect(projectMetadata.projectType, FlutterProjectType.app);
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.root]?.createRevision, 'abcdefg');
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.root]?.baseRevision, 'baserevision');
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.ios]?.createRevision, 'abcdefg');
+    expect(projectMetadata.migrateConfig.platformConfigs[SupportedPlatform.ios]?.baseRevision, 'baserevision');
+    expect(projectMetadata.migrateConfig.platformConfigs.containsKey(SupportedPlatform.android), false);
+    expect(projectMetadata.migrateConfig.unmanagedFiles[0], 'file1');
+
+    expect(logger.traceText, contains('The key `create_revision` was not found'));
   });
 }
diff --git a/packages/flutter_tools/test/integration.shard/migrate_config_test.dart b/packages/flutter_tools/test/integration.shard/migrate_config_test.dart
new file mode 100644
index 0000000000..9973356dfb
--- /dev/null
+++ b/packages/flutter_tools/test/integration.shard/migrate_config_test.dart
@@ -0,0 +1,231 @@
+// 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.
+
+// @dart = 2.8
+
+import 'package:file/file.dart';
+import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/flutter_project_metadata.dart';
+import 'package:flutter_tools/src/project.dart';
+
+import '../src/common.dart';
+import '../src/context.dart';
+import 'test_data/migrate_project.dart';
+import 'test_driver.dart';
+import 'test_utils.dart';
+
+
+void main() {
+  Directory tempDir;
+  FlutterRunTestDriver flutter;
+  Logger logger;
+
+  setUp(() async {
+    tempDir = createResolvedTempDirectorySync('run_test.');
+    flutter = FlutterRunTestDriver(tempDir);
+    logger = BufferLogger.test();
+  });
+
+  tearDown(() async {
+    await flutter.stop();
+    tryToDelete(tempDir);
+  });
+
+  testWithoutContext('parse simple config file', () async {
+    final File metadataFile = tempDir.childFile('.metadata');
+    metadataFile.createSync(recursive: true);
+    metadataFile.writeAsStringSync('''
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: fj19vkla9vnlka9vni3n808v3nch8cd
+  channel: stable
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: fj19vkla9vnlka9vni3n808v3nch8cd
+      base_revision: 93kf9v3njfa90vnidfjvn39nvi3vnie
+    - platform: android
+      create_revision: abfj19vkla9vnlka9vni3n808v3nch8cd
+      base_revision: ab93kf9v3njfa90vnidfjvn39nvi3vnie
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - lib/main.dart
+    - ios/Runner.xcodeproj/project.pbxproj
+    - lib/file1/etc.dart
+    - android/my_file.java
+''', flush: true);
+    FlutterProjectMetadata metadata = FlutterProjectMetadata(metadataFile, logger);
+
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.root].createRevision, equals('fj19vkla9vnlka9vni3n808v3nch8cd'));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.root].baseRevision, equals('93kf9v3njfa90vnidfjvn39nvi3vnie'));
+
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.android].createRevision, equals('abfj19vkla9vnlka9vni3n808v3nch8cd'));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.android].baseRevision, equals('ab93kf9v3njfa90vnidfjvn39nvi3vnie'));
+
+    expect(metadata.migrateConfig.unmanagedFiles[0], equals('lib/main.dart'));
+    expect(metadata.migrateConfig.unmanagedFiles[1], equals('ios/Runner.xcodeproj/project.pbxproj'));
+    expect(metadata.migrateConfig.unmanagedFiles[2], equals('lib/file1/etc.dart'));
+    expect(metadata.migrateConfig.unmanagedFiles[3], equals('android/my_file.java'));
+
+    metadataFile.writeAsStringSync('''
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: fj19vkla9vnlka9vni3n808v3nch8cd
+  channel: stable
+
+project_type: app
+''', flush: true);
+
+    metadata = FlutterProjectMetadata(metadataFile, logger);
+
+    expect(metadata.migrateConfig.isEmpty, equals(true));
+    expect(metadata.versionRevision, equals('fj19vkla9vnlka9vni3n808v3nch8cd'));
+    expect(metadata.versionChannel, equals('stable'));
+  });
+
+  testUsingContext('write simple config file', () async {
+    const String testCreateRevision = 'testmc9skl32nlnf23lnakcs9njr3';
+    const String testBaseRevision = 'testanas9anlnq9ba7bjhavan3kma';
+    MigrateConfig config = MigrateConfig(
+      platformConfigs: <SupportedPlatform, MigratePlatformConfig>{
+        SupportedPlatform.android: MigratePlatformConfig(createRevision: testCreateRevision, baseRevision: testBaseRevision),
+        SupportedPlatform.ios: MigratePlatformConfig(createRevision: testCreateRevision, baseRevision: testBaseRevision),
+        SupportedPlatform.root: MigratePlatformConfig(createRevision: testCreateRevision, baseRevision: testBaseRevision),
+        SupportedPlatform.windows: MigratePlatformConfig(createRevision: testCreateRevision, baseRevision: testBaseRevision),
+      },
+      unmanagedFiles: <String>[
+        'lib/main.dart',
+        'ios/Runner.xcodeproj/project.pbxproj',
+        'lib/file1/etc.dart',
+      ],
+    );
+    String outputString = config.getOutputFileString();
+    expect(outputString, equals('''
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: android
+      create_revision: $testCreateRevision
+      base_revision: $testBaseRevision
+    - platform: ios
+      create_revision: $testCreateRevision
+      base_revision: $testBaseRevision
+    - platform: root
+      create_revision: $testCreateRevision
+      base_revision: $testBaseRevision
+    - platform: windows
+      create_revision: $testCreateRevision
+      base_revision: $testBaseRevision
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'
+    - 'lib/file1/etc.dart'
+'''));
+
+    config = MigrateConfig();
+    outputString = config.getOutputFileString();
+    expect(outputString, equals(''));
+  });
+
+  testUsingContext('populate migrate config', () async {
+    // Flutter Stable 1.22.6 hash: 9b2d32b605630f28625709ebd9d78ab3016b2bf6
+    final MigrateProject project = MigrateProject('version:1.22.6_stable');
+    await project.setUpIn(tempDir);
+
+    final File metadataFile = tempDir.childFile('.metadata');
+
+    const String currentRevision = 'test_base_revision';
+    const String createRevision = 'test_create_revision';
+
+    final FlutterProjectMetadata metadata = FlutterProjectMetadata(metadataFile, logger);
+    metadata.migrateConfig.populate(
+      projectDirectory: tempDir,
+      currentRevision: currentRevision,
+      createRevision: createRevision,
+      create: true,
+      update: true,
+      logger: logger,
+    );
+
+    expect(metadata.migrateConfig.platformConfigs.length, equals(3));
+
+    final List<SupportedPlatform> keyList = List<SupportedPlatform>.from(metadata.migrateConfig.platformConfigs.keys);
+
+    expect(keyList[0], equals(SupportedPlatform.root));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.root].baseRevision, equals(currentRevision));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.root].createRevision, equals(createRevision));
+
+    expect(keyList[1], equals(SupportedPlatform.android));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.android].baseRevision, equals(currentRevision));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.android].createRevision, equals(createRevision));
+
+    expect(keyList[2], equals(SupportedPlatform.ios));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.ios].baseRevision, equals(currentRevision));
+    expect(metadata.migrateConfig.platformConfigs[SupportedPlatform.ios].createRevision, equals(createRevision));
+
+    final File metadataFileOutput = tempDir.childFile('.metadata_output');
+    metadata.writeFile(outputFile: metadataFileOutput);
+    expect(metadataFileOutput.readAsStringSync(), equals('''
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled.
+
+version:
+  revision: 9b2d32b605630f28625709ebd9d78ab3016b2bf6
+  channel: unknown
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: $createRevision
+      base_revision: $currentRevision
+    - platform: android
+      create_revision: $createRevision
+      base_revision: $currentRevision
+    - platform: ios
+      create_revision: $createRevision
+      base_revision: $currentRevision
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'
+'''));
+  });
+}
diff --git a/packages/flutter_tools/test/integration.shard/test_data/full_apps/vanilla_app_1_22_6_stable.ensure b/packages/flutter_tools/test/integration.shard/test_data/full_apps/vanilla_app_1_22_6_stable.ensure
new file mode 100644
index 0000000000..b6d130f8a8
--- /dev/null
+++ b/packages/flutter_tools/test/integration.shard/test_data/full_apps/vanilla_app_1_22_6_stable.ensure
@@ -0,0 +1 @@
+flutter/test/full_app_fixtures/vanilla  version:1.22.6_stable
diff --git a/packages/flutter_tools/test/integration.shard/test_data/migrate_project.dart b/packages/flutter_tools/test/integration.shard/test_data/migrate_project.dart
new file mode 100644
index 0000000000..e14d8b1597
--- /dev/null
+++ b/packages/flutter_tools/test/integration.shard/test_data/migrate_project.dart
@@ -0,0 +1,237 @@
+// 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.
+
+@Timeout(Duration(seconds: 600))
+
+import 'dart:io';
+import 'package:file/file.dart';
+
+import '../../src/common.dart';
+import '../test_utils.dart';
+import 'project.dart';
+
+class MigrateProject extends Project {
+  MigrateProject(this.version, {this.vanilla = true});
+
+  @override
+  Future<void> setUpIn(Directory dir, {
+    bool useDeferredLoading = false,
+    bool useSyntheticPackage = false,
+  }) async {
+    this.dir = dir;
+    _appPath = dir.path;
+    if (androidLocalProperties != null) {
+      writeFile(fileSystem.path.join(dir.path, 'android', 'local.properties'), androidLocalProperties);
+    }
+    final Directory tempDir = createResolvedTempDirectorySync('cipd_dest.');
+    final Directory depotToolsDir = createResolvedTempDirectorySync('depot_tools.');
+
+    await processManager.run(<String>[
+      'git',
+      'clone',
+      'https://chromium.googlesource.com/chromium/tools/depot_tools',
+      depotToolsDir.path,
+    ], workingDirectory: dir.path);
+
+    final File cipdFile = depotToolsDir.childFile(Platform.isWindows ? 'cipd.bat' : 'cipd');
+    await processManager.run(<String>[
+      cipdFile.path,
+      'init',
+      tempDir.path,
+      '-force',
+    ], workingDirectory: dir.path);
+
+    await processManager.run(<String>[
+      cipdFile.path,
+      'install',
+      'flutter/test/full_app_fixtures/vanilla',
+      version,
+      '-root',
+      tempDir.path,
+    ], workingDirectory: dir.path);
+
+    if (Platform.isWindows) {
+      await processManager.run(<String>[
+        'robocopy',
+        tempDir.path,
+        dir.path,
+        '*',
+        '/E',
+        '/mov',
+      ]);
+      // Add full access permissions to Users
+      await processManager.run(<String>[
+        'icacls',
+        tempDir.path,
+        '/q',
+        '/c',
+        '/t',
+        '/grant',
+        'Users:F',
+      ]);
+    } else {
+      // This cp command changes the symlinks to real files so the tool can edit them.
+      await processManager.run(<String>[
+        'cp',
+        '-R',
+        '-L',
+        '-f',
+        '${tempDir.path}/.',
+        dir.path,
+      ]);
+
+      await processManager.run(<String>[
+        'rm',
+        '-rf',
+        '.cipd',
+      ], workingDirectory: dir.path);
+
+      final List<FileSystemEntity> allFiles = dir.listSync(recursive: true);
+      for (final FileSystemEntity file in allFiles) {
+        if (file is! File) {
+          continue;
+        }
+        await processManager.run(<String>[
+          'chmod',
+          '+w',
+          file.path,
+        ], workingDirectory: dir.path);
+      }
+    }
+
+    if (!vanilla) {
+      writeFile(fileSystem.path.join(dir.path, 'lib', 'main.dart'), libMain);
+      writeFile(fileSystem.path.join(dir.path, 'lib', 'other.dart'), libOther);
+      writeFile(fileSystem.path.join(dir.path, 'pubspec.yaml'), pubspecCustom);
+    }
+    tryToDelete(tempDir);
+    tryToDelete(depotToolsDir);
+  }
+
+  final String version;
+  final bool vanilla;
+  late String _appPath;
+
+  // Maintain the same pubspec as the configured app.
+  @override
+  String get pubspec => fileSystem.file(fileSystem.path.join(_appPath, 'pubspec.yaml')).readAsStringSync();
+
+  String get androidLocalProperties => '''
+  flutter.sdk=${getFlutterRoot()}
+  ''';
+
+  String get libMain => '''
+import 'package:flutter/material.dart';
+import 'other.dart';
+
+void main() {
+  runApp(MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter Demo',
+      theme: ThemeData(
+        primarySwatch: Colors.blue,
+        visualDensity: VisualDensity.adaptivePlatformDensity,
+      ),
+      home: OtherWidget(),
+    );
+  }
+}
+
+''';
+
+  String get libOther => '''
+class OtherWidget extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Container(width: 100, height: 100);
+  }
+}
+
+''';
+
+  String get pubspecCustom => '''
+name: vanilla_app_1_22_6_stable
+description: This is a modified description from the default.
+
+# The following line prevents the package from being accidentally published to
+# pub.dev using `pub publish`. This is preferred for private packages.
+publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+
+# The following defines the version and build number for your application.
+# A version number is three numbers separated by dots, like 1.2.43
+# followed by an optional build number separated by a +.
+# Both the version and the builder number may be overridden in flutter
+# build by specifying --build-name and --build-number, respectively.
+# In Android, build-name is used as versionName while build-number used as versionCode.
+# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
+# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
+# Read more about iOS versioning at
+# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
+version: 1.0.0+1
+
+environment:
+  sdk: ">=2.6.0 <3.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+
+
+  # The following adds the Cupertino Icons font to your application.
+  # Use with the CupertinoIcons class for iOS style icons.
+  cupertino_icons: ^1.0.0
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+
+# For information on the generic Dart part of this file, see the
+# following page: https://dart.dev/tools/pub/pubspec
+
+# The following section is specific to Flutter.
+flutter:
+
+  # The following line ensures that the Material Icons font is
+  # included with your application, so that you can use the icons in
+  # the material Icons class.
+  uses-material-design: true
+
+  # To add assets to your application, add an assets section, like this:
+  assets:
+    - images/a_dot_burr.jpeg
+    - images/a_dot_ham.jpeg
+
+  # An image asset can refer to one or more resolution-specific "variants", see
+  # https://flutter.dev/assets-and-images/#resolution-aware.
+
+  # For details regarding adding assets from package dependencies, see
+  # https://flutter.dev/assets-and-images/#from-packages
+
+  # To add custom fonts to your application, add a fonts section here,
+  # in this "flutter" section. Each entry in this list should have a
+  # "family" key with the font family name, and a "fonts" key with a
+  # list giving the asset and other descriptors for the font. For
+  # example:
+  # fonts:
+  #   - family: Schyler
+  #     fonts:
+  #       - asset: fonts/Schyler-Regular.ttf
+  #       - asset: fonts/Schyler-Italic.ttf
+  #         style: italic
+  #   - family: Trajan Pro
+  #     fonts:
+  #       - asset: fonts/TrajanPro.ttf
+  #       - asset: fonts/TrajanPro_Bold.ttf
+  #         weight: 700
+  #
+  # For details regarding fonts from package dependencies,
+  # see https://flutter.dev/custom-fonts/#from-packages
+
+''';
+}
diff --git a/packages/flutter_tools/test/integration.shard/test_utils.dart b/packages/flutter_tools/test/integration.shard/test_utils.dart
index fe2af16138..94bb3f4f2a 100644
--- a/packages/flutter_tools/test/integration.shard/test_utils.dart
+++ b/packages/flutter_tools/test/integration.shard/test_utils.dart
@@ -33,7 +33,7 @@ Directory createResolvedTempDirectorySync(String prefix) {
 void writeFile(String path, String content, {bool writeFutureModifiedDate = false}) {
   final File file = fileSystem.file(path)
     ..createSync(recursive: true)
-    ..writeAsStringSync(content);
+    ..writeAsStringSync(content, flush: true);
     // Some integration tests on Windows to not see this file as being modified
     // recently enough for the hot reload to pick this change up unless the
     // modified time is written in the future.