Revert "Exit tool if a plugin supports the embedding v2 but the app doesn't (#44026)"

This missed some plugins that _do_ support the v1 embedding
(shared_preferences as one known case) so caused unexpected breakages.

This reverts commit b94c1a41.

packages/flutter_tools/lib/src/platform_plugins.dart

@@ -64,20 +64,17 @@ class AndroidPlugin extends PluginPlatform {
       'name': name,
       'package': package,
       'class': pluginClass,
-      // Mustache doesn't support complex types.
-      'supportsEmbeddingV1': _supportedEmbedings.contains('1'),
-      'supportsEmbeddingV2': _supportedEmbedings.contains('2'),
+      'usesEmbedding2': _embeddingVersion == '2',
     };
   }
 
-  Set<String> _cachedEmbeddingVersion;
+  String _cachedEmbeddingVersion;
 
   /// Returns the version of the Android embedding.
-  Set<String> get _supportedEmbedings => _cachedEmbeddingVersion ??= _getSupportedEmbeddings();
+  String get _embeddingVersion => _cachedEmbeddingVersion ??= _getEmbeddingVersion();
 
-  Set<String> _getSupportedEmbeddings() {
+  String _getEmbeddingVersion() {
     assert(pluginPath != null);
-    final Set<String> supportedEmbeddings = <String>{};
     final String baseMainPath = fs.path.join(
       pluginPath,
       'android',
@@ -116,15 +113,9 @@ class AndroidPlugin extends PluginPlatform {
     }
     if (mainClassContent
         .contains('io.flutter.embedding.engine.plugins.FlutterPlugin')) {
-      supportedEmbeddings.add('2');
-    } else {
-      supportedEmbeddings.add('1');
+      return '2';
     }
-    if (mainClassContent.contains('registerWith(Registrar registrar)') ||
-        mainClassContent.contains('registerWith(registrar: Registrar)')) {
-      supportedEmbeddings.add('1');
-    }
-    return supportedEmbeddings;
+    return '1';
   }
 }
 

packages/flutter_tools/lib/src/plugins.dart

@@ -337,14 +337,12 @@ public final class GeneratedPluginRegistrant {
     ShimPluginRegistry shimPluginRegistry = new ShimPluginRegistry(flutterEngine);
 {{/needsShim}}
 {{#plugins}}
-  {{#supportsEmbeddingV2}}
+  {{#usesEmbedding2}}
     flutterEngine.getPlugins().add(new {{package}}.{{class}}());
-  {{/supportsEmbeddingV2}}
-  {{^supportsEmbeddingV2}}
-    {{#supportsEmbeddingV1}}
+  {{/usesEmbedding2}}
+  {{^usesEmbedding2}}
     {{package}}.{{class}}.registerWith(shimPluginRegistry.registrarFor("{{package}}.{{class}}"));
-    {{/supportsEmbeddingV1}}
-  {{/supportsEmbeddingV2}}
+  {{/usesEmbedding2}}
 {{/plugins}}
   }
 }
@@ -398,24 +396,14 @@ Future<void> _writeAndroidPluginRegistrant(FlutterProject project, List<Plugin>
       // If a plugin is using an embedding version older than 2.0 and the app is using 2.0,
       // then add  shim for the old plugins.
       for (Map<String, dynamic> plugin in androidPlugins) {
-        if (plugin['supportsEmbeddingV1'] && !plugin['supportsEmbeddingV2']) {
+        if (!plugin['usesEmbedding2']) {
           templateContext['needsShim'] = true;
           break;
         }
       }
       templateContent = _androidPluginRegistryTemplateNewEmbedding;
     break;
-    case AndroidEmbeddingVersion.v1:
     default:
-      for (Map<String, dynamic> plugin in androidPlugins) {
-        if (!plugin['supportsEmbeddingV1'] && plugin['supportsEmbeddingV2']) {
-          throwToolExit(
-            'The plugin `${plugin['name']}` requires your app to be migrated to '
-            'the Android embedding v2. Follow the steps on https://flutter.dev/go/android-project-migration '
-            'and re-run this command.'
-          );
-        }
-      }
       templateContent = _androidPluginRegistryTemplateOldEmbedding;
       break;
   }

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

@@ -265,99 +265,6 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
         XcodeProjectInterpreter: () => xcodeProjectInterpreter,
       });
 
-      testUsingContext('exits the tool if an app uses the v1 embedding and a plugin only supports the v2 embedding', () async {
-        when(flutterProject.isModule).thenReturn(false);
-        when(androidProject.getEmbeddingVersion()).thenReturn(AndroidEmbeddingVersion.v1);
-
-        final Directory pluginUsingJavaAndNewEmbeddingDir =
-          fs.systemTempDirectory.createTempSync('flutter_plugin_using_java_and_new_embedding_dir.');
-        pluginUsingJavaAndNewEmbeddingDir
-          .childFile('pubspec.yaml')
-          .writeAsStringSync('''
-  flutter:
-    plugin:
-      androidPackage: plugin1
-      pluginClass: UseNewEmbedding
-  ''');
-        pluginUsingJavaAndNewEmbeddingDir
-          .childDirectory('android')
-          .childDirectory('src')
-          .childDirectory('main')
-          .childDirectory('java')
-          .childDirectory('plugin1')
-          .childFile('UseNewEmbedding.java')
-          ..createSync(recursive: true)
-          ..writeAsStringSync('import io.flutter.embedding.engine.plugins.FlutterPlugin;');
-
-        flutterProject.directory
-          .childFile('.packages')
-          .writeAsStringSync('''
-plugin1:${pluginUsingJavaAndNewEmbeddingDir.childDirectory('lib').uri.toString()}
-''');
-        await expectLater(
-          () async {
-            await injectPlugins(flutterProject);
-          },
-          throwsToolExit(
-            message: 'The plugin `plugin1` requires your app to be migrated to the Android embedding v2. '
-                     'Follow the steps on https://flutter.dev/go/android-project-migration and re-run this command.'
-          ),
-        );
-      }, overrides: <Type, Generator>{
-        FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager.any(),
-        FeatureFlags: () => featureFlags,
-        XcodeProjectInterpreter: () => xcodeProjectInterpreter,
-      });
-
-      testUsingContext('allows app use a plugin that supports v1 and v2 embedding', () async {
-        when(flutterProject.isModule).thenReturn(false);
-        when(androidProject.getEmbeddingVersion()).thenReturn(AndroidEmbeddingVersion.v1);
-
-        final Directory pluginUsingJavaAndNewEmbeddingDir =
-          fs.systemTempDirectory.createTempSync('flutter_plugin_using_java_and_new_embedding_dir.');
-        pluginUsingJavaAndNewEmbeddingDir
-          .childFile('pubspec.yaml')
-          .writeAsStringSync('''
-  flutter:
-    plugin:
-      androidPackage: plugin1
-      pluginClass: UseNewEmbedding
-  ''');
-        pluginUsingJavaAndNewEmbeddingDir
-          .childDirectory('android')
-          .childDirectory('src')
-          .childDirectory('main')
-          .childDirectory('java')
-          .childDirectory('plugin1')
-          .childFile('UseNewEmbedding.java')
-          ..createSync(recursive: true)
-          ..writeAsStringSync(
-            'import io.flutter.embedding.engine.plugins.FlutterPlugin;'
-            'registerWith(Registrar registrar)'
-          );
-
-        flutterProject.directory
-          .childFile('.packages')
-          .writeAsStringSync('''
-plugin1:${pluginUsingJavaAndNewEmbeddingDir.childDirectory('lib').uri.toString()}
-''');
-        await injectPlugins(flutterProject);
-
-        final File registrant = flutterProject.directory
-          .childDirectory(fs.path.join('android', 'app', 'src', 'main', 'java', 'io', 'flutter', 'plugins'))
-          .childFile('GeneratedPluginRegistrant.java');
-
-        expect(registrant.existsSync(), isTrue);
-        expect(registrant.readAsStringSync(), contains('package io.flutter.plugins'));
-        expect(registrant.readAsStringSync(), contains('class GeneratedPluginRegistrant'));
-      }, overrides: <Type, Generator>{
-        FileSystem: () => fs,
-        ProcessManager: () => FakeProcessManager.any(),
-        FeatureFlags: () => featureFlags,
-        XcodeProjectInterpreter: () => xcodeProjectInterpreter,
-      });
-
       testUsingContext('Registrant doesn\'t use new embedding if app doesn\'t use new embedding', () async {
         when(flutterProject.isModule).thenReturn(false);
         when(androidProject.getEmbeddingVersion()).thenReturn(AndroidEmbeddingVersion.v1);