[flutter_tools] generate a synthetic flutter_gen package on pub get (#61261)

Allow configuring the flutter_manifest to support a synthetic package, this is done through flutter: generate: true.

When running pub get, insert a flutter_gen entry into the packages if it does not already exist. This points to .dart_tool/flutter_gen, which can be updated to contain the generated intl sources (But doesn't currently)

Adds an integration test that verifies this code can be run and imported when enabled.

Part of #60914

packages/flutter_tools/lib/src/build_runner/build_runner.dart

@@ -104,6 +104,7 @@ class BuildRunner extends CodeGenerator {
         directory: generatedDirectory.path,
         upgrade: false,
         checkLastModified: false,
+        generateSyntheticPackage: false,
       );
       if (!scriptIdFile.existsSync()) {
         scriptIdFile.createSync(recursive: true);

packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart

@@ -448,7 +448,8 @@ class _ResidentWebRunner extends ResidentWebRunner {
         // This will result in a NoSuchMethodError thrown by injected_handler.darts
         await pub.get(
           context: PubContext.pubGet,
-          directory: globals.fs.path.join(Cache.flutterRoot, 'packages', 'flutter_tools')
+          directory: globals.fs.path.join(Cache.flutterRoot, 'packages', 'flutter_tools'),
+          generateSyntheticPackage: false,
         );
 
         final ExpressionCompiler expressionCompiler =

packages/flutter_tools/lib/src/build_runner/web_compilation_delegate.dart

@@ -211,6 +211,7 @@ class BuildDaemonCreator {
       await pub.get(
         context: PubContext.pubGet,
         directory: globals.fs.file(buildScriptPackages).parent.path,
+        generateSyntheticPackage: false,
       );
     }
     final String flutterWebSdk = globals.artifacts.getArtifactPath(Artifact.flutterWebSdk);

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

@@ -543,6 +543,7 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
         context: PubContext.create,
         directory: directory.path,
         offline: boolArg('offline'),
+        generateSyntheticPackage: false,
       );
       final FlutterProject project = FlutterProject.fromDirectory(directory);
       await project.ensureReadyForPlatformSpecificTooling(checkProjects: false);
@@ -562,6 +563,7 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
         context: PubContext.createPackage,
         directory: directory.path,
         offline: boolArg('offline'),
+        generateSyntheticPackage: false,
       );
     }
     return generatedCount;
@@ -606,6 +608,7 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
         context: PubContext.createPlugin,
         directory: directory.path,
         offline: boolArg('offline'),
+        generateSyntheticPackage: false,
       );
     }
 
@@ -674,7 +677,12 @@ https://flutter.dev/docs/development/packages-and-plugins/developing-packages#pl
     }
 
     if (boolArg('pub')) {
-      await pub.get(context: PubContext.create, directory: directory.path, offline: boolArg('offline'));
+      await pub.get(
+        context: PubContext.create,
+        directory: directory.path,
+        offline: boolArg('offline'),
+        generateSyntheticPackage: false,
+      );
       await project.ensureReadyForPlatformSpecificTooling(checkProjects: pluginExampleApp);
     }
     if (templateContext['android'] == true) {

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

@@ -88,7 +88,7 @@ class PackagesGetCommand extends FlutterCommand {
     return usageValues;
   }
 
-  Future<void> _runPubGet(String directory) async {
+  Future<void> _runPubGet(String directory, FlutterProject flutterProject) async {
     final Stopwatch pubGetTimer = Stopwatch()..start();
     try {
       await pub.get(context: PubContext.pubGet,
@@ -96,6 +96,7 @@ class PackagesGetCommand extends FlutterCommand {
         upgrade: upgrade ,
         offline: boolArg('offline'),
         checkLastModified: false,
+        generateSyntheticPackage: flutterProject.manifest.generateSyntheticPackage,
       );
       pubGetTimer.stop();
       globals.flutterUsage.sendTiming('pub', 'get', pubGetTimer.elapsed, label: 'success');
@@ -121,15 +122,15 @@ class PackagesGetCommand extends FlutterCommand {
        '${ workingDirectory ?? "current working directory" }.'
       );
     }
-
-    await _runPubGet(target);
     final FlutterProject rootProject = FlutterProject.fromPath(target);
+
+    await _runPubGet(target, rootProject);
     await rootProject.ensureReadyForPlatformSpecificTooling(checkProjects: true);
 
     // Get/upgrade packages in example app as well
     if (rootProject.hasExampleApp) {
       final FlutterProject exampleProject = rootProject.example;
-      await _runPubGet(exampleProject.directory.path);
+      await _runPubGet(exampleProject.directory.path, exampleProject);
       await exampleProject.ensureReadyForPlatformSpecificTooling(checkProjects: true);
     }
 

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

@@ -163,15 +163,19 @@ class TestCommand extends FlutterCommand {
         "called *_test.dart and must reside in the package's 'test' "
         'directory (or one of its subdirectories).');
     }
+    final FlutterProject flutterProject = FlutterProject.current();
     if (shouldRunPub) {
-      await pub.get(context: PubContext.getVerifyContext(name), skipPubspecYamlCheck: true);
+      await pub.get(
+        context: PubContext.getVerifyContext(name),
+        skipPubspecYamlCheck: true,
+        generateSyntheticPackage: flutterProject.manifest.generateSyntheticPackage,
+      );
     }
     final bool buildTestAssets = boolArg('test-assets');
     final List<String> names = stringsArg('name');
     final List<String> plainNames = stringsArg('plain-name');
     final String tags = stringArg('tags');
     final String excludeTags = stringArg('exclude-tags');
-    final FlutterProject flutterProject = FlutterProject.current();
 
     if (buildTestAssets && flutterProject.manifest.assets.isNotEmpty) {
       await _buildTestAsset();
@@ -222,7 +226,7 @@ class TestCommand extends FlutterCommand {
     final bool machine = boolArg('machine');
     CoverageCollector collector;
     if (boolArg('coverage') || boolArg('merge-coverage')) {
-      final String projectName = FlutterProject.current().manifest.appName;
+      final String projectName = flutterProject.manifest.appName;
       collector = CoverageCollector(
         verbose: !machine,
         libraryPredicate: (String libraryName) => libraryName.contains(projectName),

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

@@ -308,6 +308,7 @@ class UpdatePackagesCommand extends FlutterCommand {
           flutterRootOverride: upgrade
             ? temporaryFlutterSdk.path
             : null,
+          generateSyntheticPackage: false,
         );
         // Cleanup the temporary SDK
         try {
@@ -387,6 +388,7 @@ class UpdatePackagesCommand extends FlutterCommand {
         directory: dir.path,
         checkLastModified: false,
         offline: offline,
+        generateSyntheticPackage: false,
       );
       count += 1;
     }

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

@@ -294,7 +294,13 @@ class UpgradeCommandRunner {
     final String projectRoot = findProjectRoot();
     if (projectRoot != null) {
       globals.printStatus('');
-      await pub.get(context: PubContext.pubUpgrade, directory: projectRoot, upgrade: true, checkLastModified: false);
+      await pub.get(
+        context: PubContext.pubUpgrade,
+        directory: projectRoot,
+        upgrade: true,
+        checkLastModified: false,
+        generateSyntheticPackage: false,
+      );
     }
   }
 

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

@@ -154,6 +154,7 @@ class VersionCommand extends FlutterCommand {
         directory: projectRoot,
         upgrade: true,
         checkLastModified: false,
+        generateSyntheticPackage: false,
       );
     }
 

packages/flutter_tools/lib/src/context_runner.dart

@@ -207,6 +207,7 @@ Future<T> runInContext<T>(
         botDetector: globals.botDetector,
         platform: globals.platform,
         usage: globals.flutterUsage,
+        toolStampFile: globals.cache.getStampFileFor('flutter_tools'),
       ),
       ShutdownHooks: () => ShutdownHooks(logger: globals.logger),
       Stdio: () => Stdio(),

packages/flutter_tools/lib/src/dart/pub.dart

@@ -5,6 +5,7 @@
 import 'dart:async';
 
 import 'package:meta/meta.dart';
+import 'package:package_config/package_config.dart';
 import 'package:process/process.dart';
 
 import '../base/bot_detector.dart';
@@ -16,6 +17,7 @@ import '../base/logger.dart';
 import '../base/platform.dart';
 import '../base/process.dart';
 import '../cache.dart';
+import '../dart/package_map.dart';
 import '../reporting/reporting.dart';
 
 /// The [Pub] instance.
@@ -39,7 +41,7 @@ class PubContext {
     for (final String item in _values) {
       if (!_validContext.hasMatch(item)) {
         throw ArgumentError.value(
-            _values, 'value', 'Must match RegExp ${_validContext.pattern}');
+          _values, 'value', 'Must match RegExp ${_validContext.pattern}');
       }
     }
   }
@@ -80,6 +82,7 @@ abstract class Pub {
     @required Platform platform,
     @required BotDetector botDetector,
     @required Usage usage,
+    File toolStampFile,
   }) = _DefaultPub;
 
   /// Runs `pub get`.
@@ -94,6 +97,7 @@ abstract class Pub {
     bool offline = false,
     bool checkLastModified = true,
     bool skipPubspecYamlCheck = false,
+    bool generateSyntheticPackage = false,
     String flutterRootOverride,
   });
 
@@ -139,7 +143,9 @@ class _DefaultPub implements Pub {
     @required Platform platform,
     @required BotDetector botDetector,
     @required Usage usage,
-  }) : _fileSystem = fileSystem,
+    File toolStampFile,
+  }) : _toolStampFile = toolStampFile,
+       _fileSystem = fileSystem,
        _logger = logger,
        _platform = platform,
        _botDetector = botDetector,
@@ -155,6 +161,7 @@ class _DefaultPub implements Pub {
   final Platform _platform;
   final BotDetector _botDetector;
   final Usage _usage;
+  final File _toolStampFile;
 
   @override
   Future<void> get({
@@ -165,6 +172,7 @@ class _DefaultPub implements Pub {
     bool offline = false,
     bool checkLastModified = true,
     bool skipPubspecYamlCheck = false,
+    bool generateSyntheticPackage = false,
     String flutterRootOverride,
   }) async {
     directory ??= _fileSystem.currentDirectory.path;
@@ -173,6 +181,7 @@ class _DefaultPub implements Pub {
       _fileSystem.path.join(directory, 'pubspec.yaml'));
     final File packageConfigFile = _fileSystem.file(
       _fileSystem.path.join(directory, '.dart_tool', 'package_config.json'));
+    final Directory generatedDirectory = _fileSystem.directory(_fileSystem.path.join(directory, '.dart_tool', 'flutter_gen'));
 
     if (!skipPubspecYamlCheck && !pubSpecYaml.existsSync()) {
       if (!skipIfAbsent) {
@@ -242,6 +251,10 @@ class _DefaultPub implements Pub {
         'The time now is: $now'
       );
     }
+    // Insert references to synthetic flutter package.
+    if (generateSyntheticPackage) {
+      await _updatePackageConfig(packageConfigFile, generatedDirectory);
+    }
   }
 
   @override
@@ -387,6 +400,12 @@ class _DefaultPub implements Pub {
     if (pubSpecYaml.lastModifiedSync().isAfter(dotPackagesLastModified)) {
       return true;
     }
+
+    if (_toolStampFile != null &&
+        _toolStampFile.existsSync() &&
+        _toolStampFile.lastModifiedSync().isAfter(dotPackagesLastModified)) {
+      return true;
+    }
     return false;
   }
 
@@ -439,4 +458,27 @@ class _DefaultPub implements Pub {
     }
     return environment;
   }
+
+  /// Insert the flutter_gen synthetic package into the package configuration file if
+  /// there is an l10n.yaml.
+  Future<void> _updatePackageConfig(File packageConfigFile, Directory generatedDirectory) async {
+    if (!packageConfigFile.existsSync()) {
+      return;
+    }
+    final PackageConfig packageConfig = await loadPackageConfigWithLogging(packageConfigFile, logger: _logger);
+    final Package flutterGen = Package('flutter_gen', generatedDirectory.uri, languageVersion: LanguageVersion(2, 8));
+    if (packageConfig.packages.any((Package package) => package.name == 'flutter_gen')) {
+      return;
+    }
+    final PackageConfig newPackageConfig = PackageConfig(
+      <Package>[
+        ...packageConfig.packages,
+        flutterGen,
+      ],
+    );
+    // There is no current API for saving a package_config without hitting the real filesystem.
+    if (packageConfigFile.fileSystem is LocalFileSystem) {
+      await savePackageConfig(newPackageConfig, packageConfigFile.parent.parent);
+    }
+  }
 }

packages/flutter_tools/lib/src/flutter_manifest.dart

@@ -279,6 +279,26 @@ class FlutterManifest {
     }
     return fonts;
   }
+
+  /// Whether a synthetic flutter_gen package should be generated.
+  ///
+  /// This can be provided to the [Pub] interface to inject a new entry
+  /// into the package_config.json file which points to `.dart_tool/flutter_gen`.
+  ///
+  /// This allows generated source code to be imported using a package
+  /// alias.
+  bool get generateSyntheticPackage => _generateSyntheticPackage ??= _computeGenerateSyntheticPackage();
+  bool _generateSyntheticPackage;
+  bool _computeGenerateSyntheticPackage() {
+    if (!_flutterDescriptor.containsKey('generate')) {
+      return false;
+    }
+    final Object value = _flutterDescriptor['generate'];
+    if (value is! bool) {
+      return false;
+    }
+    return value as bool;
+  }
 }
 
 class Font {
@@ -438,6 +458,8 @@ void _validateFlutter(YamlMap yaml, List<String> errors) {
         final List<String> pluginErrors = Plugin.validatePluginYaml(kvp.value as YamlMap);
         errors.addAll(pluginErrors);
         break;
+      case 'generate':
+        break;
       default:
         errors.add('Unexpected child "${kvp.key}" found under "flutter".');
         break;

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

@@ -845,10 +845,13 @@ abstract class FlutterCommand extends Command<void> {
     await validateCommand();
 
     if (shouldRunPub) {
-      await pub.get(context: PubContext.getVerifyContext(name));
+      final FlutterProject project = FlutterProject.current();
+      await pub.get(
+        context: PubContext.getVerifyContext(name),
+        generateSyntheticPackage: project.manifest.generateSyntheticPackage,
+      );
       // All done updating dependencies. Release the cache lock.
       Cache.releaseLock();
-      final FlutterProject project = FlutterProject.current();
       await project.ensureReadyForPlatformSpecificTooling(checkProjects: true);
     } else {
       Cache.releaseLock();

packages/flutter_tools/lib/src/template.dart

@@ -301,5 +301,6 @@ Future<void> _ensurePackageDependencies(String packagePath) async {
   await pub.get(
     context: PubContext.pubGet,
     directory: packagePath,
+    generateSyntheticPackage: false,
   );
 }

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

@@ -77,7 +77,11 @@ void main() {
         botDetector: globals.botDetector,
         usage: globals.flutterUsage,
       );
-      await pub.get(context: PubContext.flutterTests, directory: tempDir.path);
+      await pub.get(
+        context: PubContext.flutterTests,
+        directory: tempDir.path,
+        generateSyntheticPackage: false,
+      );
 
       server = AnalysisServer(
         globals.artifacts.getArtifactPath(Artifact.engineDartSdkPath),
@@ -111,8 +115,13 @@ void main() {
       platform: const LocalPlatform(),
       usage: globals.flutterUsage,
       botDetector: globals.botDetector,
+      toolStampFile: globals.fs.file('test'),
+    );
+    await pub.get(
+      context: PubContext.flutterTests,
+      directory: tempDir.path,
+      generateSyntheticPackage: false,
     );
-    await pub.get(context: PubContext.flutterTests, directory: tempDir.path);
 
       server = AnalysisServer(
         globals.artifacts.getArtifactPath(Artifact.engineDartSdkPath),

packages/flutter_tools/test/general.shard/dart/pub_get_test.dart

@@ -197,10 +197,10 @@ void main() {
   });
 
   testWithoutContext('analytics sent on success', () async {
-    MockDirectory.findCache = true;
+    final FileSystem fileSystem = MemoryFileSystem.test();
     final MockUsage usage = MockUsage();
     final Pub pub = Pub(
-      fileSystem: MockFileSystem(),
+      fileSystem: fileSystem,
       logger: BufferLogger.test(),
       processManager: MockProcessManager(0),
       botDetector: const BotDetectorAlwaysNo(),
@@ -211,8 +211,16 @@ void main() {
         }
       ),
     );
+    fileSystem.file('pubspec.yaml').createSync();
+    fileSystem.file('.dart_tool/package_config.json')
+      ..createSync(recursive: true)
+      ..writeAsStringSync('{"configVersion": 2,"packages": []}');
 
-    await pub.get(context: PubContext.flutterTests, checkLastModified: false);
+    await pub.get(
+      context: PubContext.flutterTests,
+      generateSyntheticPackage: true,
+      checkLastModified: false,
+    );
 
     verify(usage.sendEvent('pub-result', 'flutter-tests', label: 'success')).called(1);
   });
@@ -242,10 +250,10 @@ void main() {
   });
 
   testWithoutContext('analytics sent on failed version solve', () async {
-    MockDirectory.findCache = true;
     final MockUsage usage = MockUsage();
+    final FileSystem fileSystem = MemoryFileSystem.test();
     final Pub pub = Pub(
-      fileSystem: MockFileSystem(),
+      fileSystem: fileSystem,
       logger: BufferLogger.test(),
       processManager: MockProcessManager(
         1,
@@ -259,6 +267,7 @@ void main() {
       usage: usage,
       botDetector: const BotDetectorAlwaysNo(),
     );
+    fileSystem.file('pubspec.yaml').writeAsStringSync('name: foo');
 
     try {
       await pub.get(context: PubContext.flutterTests, checkLastModified: false);

packages/flutter_tools/test/general.shard/flutter_manifest_test.dart

@@ -82,6 +82,60 @@ flutter:
     expect(flutterManifest.usesMaterialDesign, true);
   });
 
+  testWithoutContext('FlutterManifest knows if generate is provided', () async {
+    const String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  generate: true
+''';
+    final BufferLogger logger = BufferLogger.test();
+    final FlutterManifest flutterManifest = FlutterManifest.createFromString(
+      manifest,
+      logger: logger,
+    );
+
+    expect(flutterManifest.generateSyntheticPackage, true);
+  });
+
+  testWithoutContext('FlutterManifest can parse invalid generate key', () async {
+    const String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  generate: "invalid"
+''';
+    final BufferLogger logger = BufferLogger.test();
+    final FlutterManifest flutterManifest = FlutterManifest.createFromString(
+      manifest,
+      logger: logger,
+    );
+
+    expect(flutterManifest.generateSyntheticPackage, false);
+  });
+
+  testWithoutContext('FlutterManifest knows if generate is disabled', () async {
+    const String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  generate: false
+''';
+    final BufferLogger logger = BufferLogger.test();
+    final FlutterManifest flutterManifest = FlutterManifest.createFromString(
+      manifest,
+      logger: logger,
+    );
+
+    expect(flutterManifest.generateSyntheticPackage, false);
+  });
+
   testWithoutContext('FlutterManifest has two assets', () async {
     const String manifest = '''
 name: test

packages/flutter_tools/test/general.shard/resident_web_runner_test.dart

@@ -297,6 +297,7 @@ void main() {
     verify(pub.get(
       context: PubContext.pubGet,
       directory: anyNamed('directory'),
+      generateSyntheticPackage: false,
     )).called(1);
 
     expect(bufferLogger.statusText, contains('Debug service listening on ws://127.0.0.1/abcd/'));

packages/flutter_tools/test/integration.shard/flutter_gen_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 'package:file/file.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+
+import '../src/common.dart';
+import 'test_data/basic_project.dart';
+import 'test_driver.dart';
+import 'test_utils.dart';
+
+void main() {
+  Directory tempDir;
+  final BasicProjectWithFlutterGen project = BasicProjectWithFlutterGen();
+  FlutterRunTestDriver flutter;
+
+  setUp(() async {
+    tempDir = createResolvedTempDirectorySync('run_test.');
+    await project.setUpIn(tempDir);
+    flutter = FlutterRunTestDriver(tempDir);
+  });
+
+  tearDown(() async {
+    await flutter.stop();
+    tryToDelete(tempDir);
+  });
+
+  test('can correctly reference flutter generated code.', () async {
+    await flutter.run();
+  });
+}

packages/flutter_tools/test/integration.shard/test_data/basic_project.dart

@@ -53,7 +53,11 @@ class BasicProject extends Project {
   int get topLevelFunctionBreakpointLine => lineContaining(main, '// TOP LEVEL BREAKPOINT');
 }
 
-class BasicProjectWithUnaryMain extends Project {
+class BasicProjectWithFlutterGen extends Project {
+  @override
+  final String generatedFile = '''
+    String x = "a";
+  ''';
 
   @override
   final String pubspec = '''
@@ -64,21 +68,42 @@ class BasicProjectWithUnaryMain extends Project {
   dependencies:
     flutter:
       sdk: flutter
+
+  flutter:
+    generate: true
   ''';
 
   @override
   final String main = r'''
   import 'dart:async';
+  import 'package:flutter_gen/flutter_gen.dart';
 
-  import 'package:flutter/material.dart';
+  void main() {}
+  ''';
+}
 
+class BasicProjectWithUnaryMain extends Project {
+
+  @override
+  final String pubspec = '''
+  name: test
+  environment:
+    sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  dependencies:
+    flutter:
+      sdk: flutter
+  ''';
+
+  @override
+  final String main = r'''
+  import 'dart:async';
+  import 'package:flutter/material.dart';
   Future<void> main(List<String> args) async {
     while (true) {
       runApp(new MyApp());
       await Future.delayed(const Duration(milliseconds: 50));
     }
   }
-
   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
@@ -89,7 +114,6 @@ class BasicProjectWithUnaryMain extends Project {
       );
     }
   }
-
   topLevelFunction() {
     print("topLevelFunction"); // TOP LEVEL BREAKPOINT
   }

packages/flutter_tools/test/integration.shard/test_data/project.dart

@@ -27,6 +27,7 @@ abstract class Project {
   String get pubspec;
   String get main;
   String get test => null;
+  String get generatedFile => null;
 
   Uri get mainDart => Uri.parse('package:test/main.dart');
 
@@ -39,6 +40,9 @@ abstract class Project {
     if (test != null) {
       writeFile(globals.fs.path.join(dir.path, 'test', 'test.dart'), test);
     }
+    if (generatedFile != null) {
+      writeFile(globals.fs.path.join(dir.path, '.dart_tool', 'flutter_gen', 'flutter_gen.dart'), generatedFile);
+    }
     writeFile(globals.fs.path.join(dir.path, 'web', 'index.html'), _kDefaultHtml);
     writePackages(dir.path);
     await getPackages(dir.path);

packages/flutter_tools/test/src/throwing_pub.dart

@@ -30,6 +30,7 @@ class ThrowingPub implements Pub {
     bool offline = false,
     bool checkLastModified = true,
     bool skipPubspecYamlCheck = false,
+    bool generateSyntheticPackage = false,
     String flutterRootOverride,
   }) {
     throw UnsupportedError('Attempted to invoke pub during test.');

packages/flutter_tools/test/template_test.dart

@@ -95,6 +95,7 @@ void main() {
     when(pub.get(
       context: PubContext.pubGet,
       directory: anyNamed('directory'),
+      generateSyntheticPackage: false,
     )).thenAnswer((Invocation invocation) async {
       // Create valid package entry.
       packagesFile.writeAsStringSync('flutter_template_images:file:///flutter_template_images');