[flutter_tools] Display "no platforms" message based on results when creating...

[flutter_tools] Display "no platforms" message based on results when creating plugins project (#70215)

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.
 
-import 'package:yaml/yaml.dart';
-
 import '../android/gradle_utils.dart' as gradle;
 import '../base/common.dart';
 import '../base/context.dart';
@@ -17,19 +15,11 @@ import '../features.dart';
 import '../flutter_manifest.dart';
 import '../flutter_project_metadata.dart';
 import '../globals.dart' as globals;
-import '../plugins.dart';
 import '../project.dart';
 import '../reporting/reporting.dart';
 import '../runner/flutter_command.dart';
 import 'create_base.dart';
 
-const String _kNoPlatformsErrorMessage = '''
-The plugin project was generated without specifying the `--platforms` flag, no new platforms are added.
-To add platforms, run `flutter create -t plugin --platforms <platforms> .` under the same
-directory. You can also find detailed instructions on how to add platforms in the `pubspec.yaml`
-at https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms.
-''';
-
 class CreateCommand extends CreateBase {
   CreateCommand() {
     addPlatformsOptions(customHelp: 'The platforms supported by this project. '
@@ -249,7 +239,8 @@ class CreateCommand extends CreateBase {
     );
 
     final String relativeDirPath = globals.fs.path.relative(projectDirPath);
-    if (!projectDir.existsSync() || projectDir.listSync().isEmpty) {
+    final bool creatingNewProject = !projectDir.existsSync() || projectDir.listSync().isEmpty;
+    if (creatingNewProject) {
       globals.printStatus('Creating project $relativeDirPath...');
     } else {
       if (sampleCode != null && !overwrite) {
@@ -295,18 +286,24 @@ class CreateCommand extends CreateBase {
           'main.dart',
       ));
       globals.printStatus('Your module code is in $relativeMainPath.');
-    } else {
+    } else if (generatePlugin) {
+      final String relativePluginPath = globals.fs.path.normalize(globals.fs.path.relative(projectDirPath));
+      final List<String> requestedPlatforms = _getUserRequestedPlatforms();
+      final String platformsString = requestedPlatforms.join(', ');
+      _printPluginDirectoryLocationMessage(relativePluginPath, projectName, platformsString);
+      if (!creatingNewProject && requestedPlatforms.isNotEmpty) {
+        _printPluginUpdatePubspecMessage(relativePluginPath, platformsString);
+      } else if (_getSupportedPlatformsInPlugin(projectDir).isEmpty){
+        globals.printError(_kNoPlatformsArgMessage);
+      }
+    } else  {
       // Tell the user the next steps.
       final FlutterProject project = FlutterProject.fromPath(projectDirPath);
       final FlutterProject app = project.hasExampleApp ? project.example : project;
       final String relativeAppPath = globals.fs.path.normalize(globals.fs.path.relative(app.directory.path));
       final String relativeAppMain = globals.fs.path.join(relativeAppPath, 'lib', 'main.dart');
-      final String relativePluginPath = globals.fs.path.normalize(globals.fs.path.relative(projectDirPath));
-      final String relativePluginMain = globals.fs.path.join(relativePluginPath, 'lib', '$projectName.dart');
 
       // Let them know a summary of the state of their tooling.
-      final List<String> platforms = _getSupportedPlatformsFromTemplateContext(templateContext);
-      final String platformsString = platforms.join(', ');
       globals.printStatus('''
 In order to run your $application, type:
 
@@ -315,14 +312,6 @@ In order to run your $application, type:
 
 Your $application code is in $relativeAppMain.
 ''');
-        if (generatePlugin) {
-          globals.printStatus('''
-Your plugin code is in $relativePluginMain.
-
-Host platform code is in the $platformsString directories under $relativePluginPath.
-To edit platform code in an IDE see https://flutter.dev/developing-packages/#edit-plugin-package.
-''');
-      }
     }
     return FlutterCommandResult.success();
   }
@@ -378,19 +367,13 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
       templateContext['linux'] = false;
       templateContext['macos'] = false;
       templateContext['windows'] = false;
-      globals.printError(_kNoPlatformsErrorMessage);
     }
     final List<String> platformsToAdd = _getSupportedPlatformsFromTemplateContext(templateContext);
 
-    final String pubspecPath = globals.fs.path.join(directory.absolute.path, 'pubspec.yaml');
-    final FlutterManifest manifest = FlutterManifest.createFromPath(pubspecPath, fileSystem: globals.fs, logger: globals.logger);
-    List<String> existingPlatforms = <String>[];
-    if (manifest.supportedPlatforms != null) {
-      existingPlatforms = manifest.supportedPlatforms.keys.toList();
-      for (final String existingPlatform in existingPlatforms) {
-        // re-generate files for existing platforms
-        templateContext[existingPlatform] = true;
-      }
+    final List<String> existingPlatforms = _getSupportedPlatformsInPlugin(directory);
+    for (final String existingPlatform in existingPlatforms) {
+      // re-generate files for existing platforms
+      templateContext[existingPlatform] = true;
     }
 
     final bool willAddPlatforms = platformsToAdd.isNotEmpty;
@@ -411,35 +394,6 @@ To edit platform code in an IDE see https://flutter.dev/developing-packages/#edi
       );
     }
 
-    final bool addPlatformsToExistingPlugin = willAddPlatforms && existingPlatforms.isNotEmpty;
-
-    if (addPlatformsToExistingPlugin) {
-      // If adding new platforms to an existing plugin project, prints
-      // a help message containing the platforms maps need to be added to the `platforms` key in the pubspec.
-      platformsToAdd.removeWhere(existingPlatforms.contains);
-      final YamlMap platformsMapToPrint = Plugin.createPlatformsYamlMap(platformsToAdd, templateContext['pluginClass'] as String, templateContext['androidIdentifier'] as String);
-      if (platformsMapToPrint.isNotEmpty) {
-        String prettyYaml = '';
-        for (final String platform in platformsMapToPrint.keys.toList().cast<String>()) {
-          prettyYaml += '$platform:\n';
-          for (final String key in (platformsMapToPrint[platform] as YamlMap).keys.toList().cast<String>()) {
-            prettyYaml += ' $key: ${platformsMapToPrint[platform][key] as String}\n';
-          }
-        }
-        globals.printStatus('''
-The `pubspec.yaml` under the project directory must be updated to support ${platformsToAdd.join(', ')},
-Add below lines to under the `platform:` key:
-''', emphasis: true);
-      globals.printStatus(prettyYaml, emphasis: true, color: TerminalColor.blue);
-      globals.printStatus('''
-If the `platforms` key does not exist in the `pubspec.yaml`, it might because that the plugin project does not
-use the multi-platforms plugin format. We highly recommend a migration to the multi-platforms plugin format.
-For detailed instructions on how to format the pubspec.yaml to support platforms using the multi-platforms format, see:
-https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms
-''', emphasis: true);
-      }
-    }
-
     final FlutterProject project = FlutterProject.fromDirectory(directory);
     final bool generateAndroid = templateContext['android'] == true;
     if (generateAndroid) {
@@ -493,4 +447,57 @@ https://flutter.dev/docs/development/packages-and-plugins/developing-packages#pl
         'macos',
     ];
   }
+
+  // Returns a list of platforms that are explicitly requested by user via `--platforms`.
+  List<String> _getUserRequestedPlatforms() {
+    if (!argResults.wasParsed('platforms')) {
+      return <String>[];
+    }
+    return stringsArg('platforms');
+  }
+}
+
+
+// Determine what platforms are supported based on generated files.
+List<String> _getSupportedPlatformsInPlugin(Directory projectDir) {
+  final String pubspecPath = globals.fs.path.join(projectDir.absolute.path, 'pubspec.yaml');
+  final FlutterManifest manifest = FlutterManifest.createFromPath(pubspecPath, fileSystem: globals.fs, logger: globals.logger);
+  final List<String> platforms = manifest.validSupportedPlatforms == null
+    ? <String>[]
+    : manifest.validSupportedPlatforms.keys.toList();
+  return platforms;
 }
+
+void _printPluginDirectoryLocationMessage(String pluginPath, String projectName, String platformsString) {
+  final String relativePluginMain = globals.fs.path.join(pluginPath, 'lib', '$projectName.dart');
+  final String relativeExampleMain = globals.fs.path.join(pluginPath, 'example', 'lib', 'main.dart');
+  globals.printStatus('''
+
+Your plugin code is in $relativePluginMain.
+
+You example app code is in $relativeExampleMain.
+
+''');
+  if (platformsString != null && platformsString.isNotEmpty) {
+    globals.printStatus('''
+Host platform code is in the $platformsString directories under $pluginPath.
+To edit platform code in an IDE see https://flutter.dev/developing-packages/#edit-plugin-package.
+
+    ''');
+  }
+}
+
+void _printPluginUpdatePubspecMessage(String pluginPath, String platformsString) {
+  globals.printStatus('''
+
+You need to update $pluginPath/pubspec.yaml to support $platformsString.
+For more information, see https://flutter.dev/go/developing-plugins.
+
+''', emphasis: true, color: TerminalColor.red);
+}
+
+const String _kNoPlatformsArgMessage = '''
+
+Must specify at least one platform using --platforms.
+For more information, see https://flutter.dev/go/developing-plugins.
+''';

packages/flutter_tools/lib/src/flutter_manifest.dart

@@ -12,6 +12,10 @@ import 'base/user_messages.dart';
 import 'base/utils.dart';
 import 'plugins.dart';
 
+const Set<String> _kValidPluginPlatforms = <String>{
+  'android', 'ios', 'web', 'windows', 'linux', 'macos'
+};
+
 /// A wrapper around the `flutter` section in the `pubspec.yaml` file.
 class FlutterManifest {
   FlutterManifest._(this._logger);
@@ -199,6 +203,20 @@ class FlutterManifest {
     return null;
   }
 
+  /// Like [supportedPlatforms], but only returns the valid platforms that are supported in flutter plugins.
+  Map<String, dynamic> get validSupportedPlatforms {
+    final Map<String, dynamic> allPlatforms = supportedPlatforms;
+    if (allPlatforms == null) {
+      return null;
+    }
+    final Map<String, dynamic> platforms = <String, dynamic>{}..addAll(supportedPlatforms);
+    platforms.removeWhere((String key, dynamic _) => !_kValidPluginPlatforms.contains(key));
+    if (platforms.isEmpty) {
+      return null;
+    }
+    return platforms;
+  }
+
   List<Map<String, dynamic>> get fontsDescriptor {
     return fonts.map((Font font) => font.descriptor).toList();
   }

packages/flutter_tools/templates/plugin/pubspec.yaml.tmpl

@@ -33,7 +33,7 @@ flutter:
     platforms:
 {{#no_platforms}}
     # This plugin project was generated without specifying any
-    # platforms with the `--platform` argument. If you see the `fake_platform` map below, remove it and
+    # platforms with the `--platform` argument. If you see the `some_platform` map below, remove it and
     # then add platforms following the instruction here:
     # https://flutter.dev/docs/development/packages-and-plugins/developing-packages#plugin-platforms
     # -------------------

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

@@ -972,6 +972,49 @@ flutter:
     expect(flutterManifest.supportedPlatforms, null);
   });
 
+  testWithoutContext('FlutterManifest validSupportedPlatforms return null if the platform keys are not valid', () {
+    const String manifest = '''
+name: test
+flutter:
+  plugin:
+    platforms:
+      some_platform:
+        pluginClass: SomeClass
+''';
+    final BufferLogger logger = BufferLogger.test();
+    final FlutterManifest flutterManifest = FlutterManifest.createFromString(
+      manifest,
+      logger: logger,
+    );
+
+    expect(flutterManifest.isPlugin, true);
+    expect(flutterManifest.validSupportedPlatforms, null);
+  });
+
+  testWithoutContext('FlutterManifest validSupportedPlatforms only returns valid platforms', () {
+    const String manifest = '''
+name: test
+flutter:
+  plugin:
+    platforms:
+      some_platform:
+        pluginClass: SomeClass
+      ios:
+        pluginClass: SomeClass
+''';
+    final BufferLogger logger = BufferLogger.test();
+    final FlutterManifest flutterManifest = FlutterManifest.createFromString(
+      manifest,
+      logger: logger,
+    );
+
+    expect(flutterManifest.isPlugin, true);
+    expect(flutterManifest.validSupportedPlatforms['ios'],
+                              <String, dynamic>{'pluginClass': 'SomeClass'});
+    expect(flutterManifest.validSupportedPlatforms['some_platform'],
+                              isNull);
+  });
+
   testWithoutContext('FlutterManifest getSupportedPlatforms returns valid platforms.', () {
     const String manifest = '''
 name: test