Migrate create command to null safety (#104484)

Author: jmagman

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

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import '../android/gradle_utils.dart' as gradle;
 import '../base/common.dart';
 import '../base/context.dart';
@@ -32,8 +30,8 @@ const String kPlatformHelp =
 
 class CreateCommand extends CreateBase {
   CreateCommand({
-    bool verboseHelp = false,
-  }) : super(verboseHelp: verboseHelp) {
+    super.verboseHelp = false,
+  }) {
     addPlatformsOptions(customHelp: kPlatformHelp);
     argParser.addOption(
       'template',
@@ -57,7 +55,6 @@ class CreateCommand extends CreateBase {
         flutterProjectTypeToString(FlutterProjectType.module): 'Generate a project to add a Flutter module to an '
             'existing Android or iOS application.',
       },
-      defaultsTo: null,
     );
     argParser.addOption(
       'sample',
@@ -66,7 +63,6 @@ class CreateCommand extends CreateBase {
         '"--template=app". The value should be the sample ID of the desired sample from the API '
         'documentation website (http://docs.flutter.dev/). An example can be found at: '
         'https://api.flutter.dev/flutter/widgets/SingleChildScrollView-class.html',
-      defaultsTo: null,
       valueHelp: 'id',
     );
     argParser.addOption(
@@ -88,7 +84,7 @@ class CreateCommand extends CreateBase {
   String get category => FlutterCommandCategory.project;
 
   @override
-  String get invocation => '${runner.executableName} $name <output directory>';
+  String get invocation => '${runner?.executableName} $name <output directory>';
 
   @override
   Future<CustomDimensions> get usageValues async {
@@ -100,8 +96,7 @@ class CreateCommand extends CreateBase {
   }
 
   // Lazy-initialize the net utilities with values from the context.
-  Net _cachedNet;
-  Net get _net => _cachedNet ??= Net(
+  late final Net _net = Net(
     httpClientFactory: context.get<HttpClientFactory>(),
     logger: globals.logger,
     platform: globals.platform,
@@ -112,25 +107,25 @@ class CreateCommand extends CreateBase {
         ? 'api.flutter.dev'
         : 'master-api.flutter.dev';
 
-  Future<String> _fetchSampleFromServer(String sampleId) async {
+  Future<String?> _fetchSampleFromServer(String sampleId) async {
     // Sanity check the sampleId
     if (sampleId.contains(RegExp(r'[^-\w\.]'))) {
       throwToolExit('Sample ID "$sampleId" contains invalid characters. Check the ID in the '
         'documentation and try again.');
     }
 
     final Uri snippetsUri = Uri.https(_snippetsHost, 'snippets/$sampleId.dart');
-    final List<int> data = await _net.fetchUrl(snippetsUri);
+    final List<int>? data = await _net.fetchUrl(snippetsUri);
     if (data == null || data.isEmpty) {
       return null;
     }
     return utf8.decode(data);
   }
 
   /// Fetches the samples index file from the Flutter docs website.
-  Future<String> _fetchSamplesIndexFromServer() async {
+  Future<String?> _fetchSamplesIndexFromServer() async {
     final Uri snippetsUri = Uri.https(_snippetsHost, 'snippets/index.json');
-    final List<int> data = await _net.fetchUrl(snippetsUri, maxAttempts: 2);
+    final List<int>? data = await _net.fetchUrl(snippetsUri, maxAttempts: 2);
     if (data == null || data.isEmpty) {
       return null;
     }
@@ -145,7 +140,7 @@ class CreateCommand extends CreateBase {
       if (outputFile.existsSync()) {
         throwToolExit('File "$outputFilePath" already exists', exitCode: 1);
       }
-      final String samplesJson = await _fetchSamplesIndexFromServer();
+      final String? samplesJson = await _fetchSamplesIndexFromServer();
       if (samplesJson == null) {
         throwToolExit('Unable to download samples', exitCode: 2);
       } else {
@@ -158,11 +153,12 @@ class CreateCommand extends CreateBase {
   }
 
   FlutterProjectType _getProjectType(Directory projectDir) {
-    FlutterProjectType template;
-    FlutterProjectType detectedProjectType;
+    FlutterProjectType? template;
+    FlutterProjectType? detectedProjectType;
     final bool metadataExists = projectDir.absolute.childFile('.metadata').existsSync();
-    if (argResults['template'] != null) {
-      template = stringToProjectType(stringArgDeprecated('template'));
+    final String? templateArgument = stringArg('template');
+    if (templateArgument != null) {
+      template = stringToProjectType(templateArgument);
     }
     // If the project directory exists and isn't empty, then try to determine the template
     // type from the project directory.
@@ -188,23 +184,25 @@ class CreateCommand extends CreateBase {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
-    if (argResults['list-samples'] != null) {
+    final String? listSamples = stringArg('list-samples');
+    if (listSamples != null) {
       // _writeSamplesJson can potentially be long-lived.
-      await _writeSamplesJson(stringArgDeprecated('list-samples'));
+      await _writeSamplesJson(listSamples);
       return FlutterCommandResult.success();
     }
 
     validateOutputDirectoryArg();
 
-    String sampleCode;
-    if (argResults['sample'] != null) {
-      if (argResults['template'] != null &&
-        stringToProjectType(stringArgDeprecated('template') ?? 'app') != FlutterProjectType.app) {
+    String? sampleCode;
+    final String? sampleArgument = stringArg('sample');
+    if (sampleArgument != null) {
+      final String? templateArgument = stringArg('template');
+      if (templateArgument != null && stringToProjectType(templateArgument) != FlutterProjectType.app) {
         throwToolExit('Cannot specify --sample with a project type other than '
           '"${flutterProjectTypeToString(FlutterProjectType.app)}"');
       }
       // Fetch the sample from the server.
-      sampleCode = await _fetchSampleFromServer(stringArgDeprecated('sample'));
+      sampleCode = await _fetchSampleFromServer(sampleArgument);
     }
 
     final FlutterProjectType template = _getProjectType(projectDir);
@@ -215,7 +213,7 @@ class CreateCommand extends CreateBase {
 
     final List<String> platforms = stringsArg('platforms');
     // `--platforms` does not support module or package.
-    if (argResults.wasParsed('platforms') && (generateModule || generatePackage)) {
+    if (argResults!.wasParsed('platforms') && (generateModule || generatePackage)) {
       final String template = generateModule ? 'module' : 'package';
       throwToolExit(
         'The "--platforms" argument is not supported in $template template.',
@@ -224,18 +222,18 @@ class CreateCommand extends CreateBase {
     } else if (platforms == null || platforms.isEmpty) {
       throwToolExit('Must specify at least one platform using --platforms',
         exitCode: 2);
-    } else if (generateFfiPlugin && argResults.wasParsed('platforms') && platforms.contains('web')) {
+    } else if (generateFfiPlugin && argResults!.wasParsed('platforms') && platforms.contains('web')) {
       throwToolExit(
         'The web platform is not supported in plugin_ffi template.',
         exitCode: 2,
       );
-    } else if (generateFfiPlugin && argResults.wasParsed('ios-language')) {
+    } else if (generateFfiPlugin && argResults!.wasParsed('ios-language')) {
       throwToolExit(
         'The "ios-language" option is not supported with the plugin_ffi '
         'template: the language will always be C or C++.',
         exitCode: 2,
       );
-    } else if (generateFfiPlugin && argResults.wasParsed('android-language')) {
+    } else if (generateFfiPlugin && argResults!.wasParsed('android-language')) {
       throwToolExit(
         'The "android-language" option is not supported with the plugin_ffi '
         'template: the language will always be C or C++.',
@@ -258,7 +256,7 @@ class CreateCommand extends CreateBase {
 
     final String dartSdk = globals.cache.dartSdkBuild;
     final bool includeIos = featureFlags.isIOSEnabled && platforms.contains('ios');
-    String developmentTeam;
+    String? developmentTeam;
     if (includeIos) {
       developmentTeam = await getCodeSigningIdentityDevelopmentTeam(
         processManager: globals.processManager,
@@ -272,7 +270,7 @@ class CreateCommand extends CreateBase {
     // The dart project_name is in snake_case, this variable is the Title Case of the Project Name.
     final String titleCaseProjectName = snakeCaseToTitleCase(projectName);
 
-    final Map<String, Object> templateContext = createTemplateContext(
+    final Map<String, Object?> templateContext = createTemplateContext(
       organization: organization,
       projectName: projectName,
       titleCaseProjectName: titleCaseProjectName,
@@ -432,12 +430,12 @@ Your $application code is in $relativeAppMain.
 
   Future<int> _generateModule(
     Directory directory,
-    Map<String, dynamic> templateContext, {
+    Map<String, Object?> templateContext, {
     bool overwrite = false,
     bool printStatusWhenWriting = true,
   }) async {
     int generatedCount = 0;
-    final String description = argResults.wasParsed('description')
+    final String? description = argResults!.wasParsed('description')
         ? stringArgDeprecated('description')
         : 'A new Flutter module project.';
     templateContext['description'] = description;
@@ -453,7 +451,6 @@ Your $application code is in $relativeAppMain.
         context: PubContext.create,
         directory: directory.path,
         offline: boolArgDeprecated('offline'),
-        generateSyntheticPackage: false,
       );
       final FlutterProject project = FlutterProject.fromDirectory(directory);
       await project.ensureReadyForPlatformSpecificTooling(
@@ -466,12 +463,12 @@ Your $application code is in $relativeAppMain.
 
   Future<int> _generatePackage(
     Directory directory,
-    Map<String, dynamic> templateContext, {
+    Map<String, Object?> templateContext, {
     bool overwrite = false,
     bool printStatusWhenWriting = true,
   }) async {
     int generatedCount = 0;
-    final String description = argResults.wasParsed('description')
+    final String? description = argResults!.wasParsed('description')
         ? stringArgDeprecated('description')
         : 'A new Flutter package project.';
     templateContext['description'] = description;
@@ -487,21 +484,20 @@ Your $application code is in $relativeAppMain.
         context: PubContext.createPackage,
         directory: directory.path,
         offline: boolArgDeprecated('offline'),
-        generateSyntheticPackage: false,
       );
     }
     return generatedCount;
   }
 
   Future<int> _generateMethodChannelPlugin(
     Directory directory,
-    Map<String, dynamic> templateContext, {
+    Map<String, Object?> templateContext, {
     bool overwrite = false,
     bool printStatusWhenWriting = true,
-    FlutterProjectType projectType,
+    required FlutterProjectType projectType,
   }) async {
     // Plugins only add a platform if it was requested explicitly by the user.
-    if (!argResults.wasParsed('platforms')) {
+    if (!argResults!.wasParsed('platforms')) {
       for (final String platform in kAllCreatePlatforms) {
         templateContext[platform] = false;
       }
@@ -517,7 +513,7 @@ Your $application code is in $relativeAppMain.
     final bool willAddPlatforms = platformsToAdd.isNotEmpty;
     templateContext['no_platforms'] = !willAddPlatforms;
     int generatedCount = 0;
-    final String description = argResults.wasParsed('description')
+    final String? description = argResults!.wasParsed('description')
         ? stringArgDeprecated('description')
         : 'A new Flutter plugin project.';
     templateContext['description'] = description;
@@ -534,7 +530,6 @@ Your $application code is in $relativeAppMain.
         context: PubContext.createPlugin,
         directory: directory.path,
         offline: boolArgDeprecated('offline'),
-        generateSyntheticPackage: false,
       );
     }
 
@@ -545,9 +540,9 @@ Your $application code is in $relativeAppMain.
         project: project, requireAndroidSdk: false);
     }
 
-    final String projectName = templateContext['projectName'] as String;
-    final String organization = templateContext['organization'] as String;
-    final String androidPluginIdentifier = templateContext['androidIdentifier'] as String;
+    final String? projectName = templateContext['projectName'] as String?;
+    final String organization = templateContext['organization']! as String; // Required to make the context.
+    final String? androidPluginIdentifier = templateContext['androidIdentifier'] as String?;
     final String exampleProjectName = '${projectName}_example';
     templateContext['projectName'] = exampleProjectName;
     templateContext['androidIdentifier'] = CreateBase.createAndroidIdentifier(organization, exampleProjectName);
@@ -572,13 +567,13 @@ Your $application code is in $relativeAppMain.
 
   Future<int> _generateFfiPlugin(
     Directory directory,
-    Map<String, dynamic> templateContext, {
+    Map<String, Object?> templateContext, {
     bool overwrite = false,
     bool printStatusWhenWriting = true,
-    FlutterProjectType projectType,
+    required FlutterProjectType projectType,
   }) async {
     // Plugins only add a platform if it was requested explicitly by the user.
-    if (!argResults.wasParsed('platforms')) {
+    if (!argResults!.wasParsed('platforms')) {
       for (final String platform in kAllCreatePlatforms) {
         templateContext[platform] = false;
       }
@@ -596,7 +591,7 @@ Your $application code is in $relativeAppMain.
     final bool willAddPlatforms = platformsToAdd.isNotEmpty;
     templateContext['no_platforms'] = !willAddPlatforms;
     int generatedCount = 0;
-    final String description = argResults.wasParsed('description')
+    final String? description = argResults!.wasParsed('description')
         ? stringArgDeprecated('description')
         : 'A new Flutter FFI plugin project.';
     templateContext['description'] = description;
@@ -613,7 +608,6 @@ Your $application code is in $relativeAppMain.
         context: PubContext.createPlugin,
         directory: directory.path,
         offline: boolArgDeprecated('offline'),
-        generateSyntheticPackage: false,
       );
     }
 
@@ -623,9 +617,9 @@ Your $application code is in $relativeAppMain.
       gradle.updateLocalProperties(project: project, requireAndroidSdk: false);
     }
 
-    final String projectName = templateContext['projectName'] as String;
-    final String organization = templateContext['organization'] as String;
-    final String androidPluginIdentifier = templateContext['androidIdentifier'] as String;
+    final String? projectName = templateContext['projectName'] as String?;
+    final String organization = templateContext['organization']! as String; // Required to make the context.
+    final String? androidPluginIdentifier = templateContext['androidIdentifier'] as String?;
     final String exampleProjectName = '${projectName}_example';
     templateContext['projectName'] = exampleProjectName;
     templateContext['androidIdentifier'] = CreateBase.createAndroidIdentifier(organization, exampleProjectName);
@@ -662,7 +656,7 @@ Your $application code is in $relativeAppMain.
     return -files.length;
   }
 
-  List<String> _getSupportedPlatformsFromTemplateContext(Map<String, dynamic> templateContext) {
+  List<String> _getSupportedPlatformsFromTemplateContext(Map<String, Object?> templateContext) {
     return <String>[
       for (String platform in kAllCreatePlatforms)
         if (templateContext[platform] == true) platform,
@@ -671,7 +665,7 @@ Your $application code is in $relativeAppMain.
 
   // Returns a list of platforms that are explicitly requested by user via `--platforms`.
   List<String> _getUserRequestedPlatforms() {
-    if (!argResults.wasParsed('platforms')) {
+    if (!argResults!.wasParsed('platforms')) {
       return <String>[];
     }
     return stringsArg('platforms');
@@ -682,10 +676,11 @@ Your $application code is in $relativeAppMain.
 // Determine what platforms are supported based on generated files.
 List<String> _getSupportedPlatformsInPlugin(Directory projectDir) {
   final String pubspecPath = globals.fs.path.join(projectDir.absolute.path, 'pubspec.yaml');
-  final FlutterManifest manifest = FlutterManifest.createFromPath(pubspecPath, fileSystem: globals.fs, logger: globals.logger);
-  final List<String> platforms = manifest.validSupportedPlatforms == null
+  final FlutterManifest? manifest = FlutterManifest.createFromPath(pubspecPath, fileSystem: globals.fs, logger: globals.logger);
+  final Map<String, Object?>? validSupportedPlatforms = manifest?.validSupportedPlatforms;
+  final List<String> platforms = validSupportedPlatforms == null
     ? <String>[]
-    : manifest.validSupportedPlatforms.keys.toList();
+    : validSupportedPlatforms.keys.toList();
   return platforms;
 }