Don't read AndroidManifest.xml if it doesn't exit (#43669)

packages/flutter_tools/lib/src/plugins.dart

@@ -361,8 +361,11 @@ List<Map<String, dynamic>> _extractPlatformMaps(List<Plugin> plugins, String typ
 /// [project] is using.
 String _getAndroidEmbeddingVersion(FlutterProject project) {
   assert(project.android != null);
+
   final File androidManifest = project.android.appManifestFile;
-  assert(androidManifest.existsSync());
+  if (androidManifest == null || !androidManifest.existsSync()) {
+    return '1';
+  }
   xml.XmlDocument document;
   try {
     document = xml.parse(androidManifest.readAsStringSync());

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

@@ -16,6 +16,7 @@ import '../src/common.dart';
 import '../src/context.dart';
 
 void main() {
+  group('plugins', () {
     FileSystem fs;
     MockFlutterProject flutterProject;
     MockIosProject iosProject;
@@ -60,12 +61,12 @@ void main() {
     // Makes the dummy package pointed to by packagesFile look like a plugin.
     void configureDummyPackageAsPlugin() {
       dummyPackageDirectory.parent.childFile('pubspec.yaml')..createSync(recursive: true)..writeAsStringSync('''
-flutter:
+  flutter:
     plugin:
       platforms:
         ios:
           pluginClass: FLESomePlugin
-''');
+  ''');
     }
 
     // Creates the files that would indicate that pod install has run for the
@@ -125,20 +126,20 @@ flutter:
       MockXcodeProjectInterpreter xcodeProjectInterpreter;
 
       const String kAndroidManifestUsingOldEmbedding = '''
-<manifest>
+  <manifest>
       <application>
       </application>
-</manifest>
-''';
+  </manifest>
+  ''';
       const String kAndroidManifestUsingNewEmbedding = '''
-<manifest>
+  <manifest>
       <application>
           <meta-data
               android:name="flutterEmbedding"
               android:value="2" />
       </application>
-</manifest>
-''';
+  </manifest>
+  ''';
 
       setUp(() {
         featureFlags = MockFeatureFlags();
@@ -216,11 +217,11 @@ flutter:
         pluginUsingJavaAndNewEmbeddingDir
           .childFile('pubspec.yaml')
           .writeAsStringSync('''
-flutter:
+  flutter:
     plugin:
       androidPackage: plugin1
       pluginClass: UseNewEmbedding
-''');
+  ''');
         pluginUsingJavaAndNewEmbeddingDir
           .childDirectory('android')
           .childDirectory('src')
@@ -236,11 +237,11 @@ flutter:
         pluginUsingKotlinAndNewEmbeddingDir
           .childFile('pubspec.yaml')
           .writeAsStringSync('''
-flutter:
+  flutter:
     plugin:
       androidPackage: plugin2
       pluginClass: UseNewEmbedding
-''');
+  ''');
         pluginUsingKotlinAndNewEmbeddingDir
           .childDirectory('android')
           .childDirectory('src')
@@ -256,11 +257,11 @@ flutter:
         pluginUsingOldEmbeddingDir
           .childFile('pubspec.yaml')
           .writeAsStringSync('''
-flutter:
+  flutter:
     plugin:
       androidPackage: plugin3
       pluginClass: UseOldEmbedding
-''');
+  ''');
         pluginUsingOldEmbeddingDir
           .childDirectory('android')
           .childDirectory('src')
@@ -398,6 +399,20 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
         FeatureFlags: () => featureFlags,
       });
 
+      testUsingContext('Does not throw when AndroidManifest.xml is not found', () async {
+        when(flutterProject.isModule).thenReturn(false);
+
+        final File manifest = MockFile();
+        when(manifest.existsSync()).thenReturn(false);
+        when(androidProject.appManifestFile).thenReturn(manifest);
+
+        await injectPlugins(flutterProject);
+
+      }, overrides: <Type, Generator>{
+        FileSystem: () => fs,
+        ProcessManager: () => FakeProcessManager.any(),
+      });
+
       testUsingContext('Registrant for web doesn\'t escape slashes in imports', () async {
         when(flutterProject.isModule).thenReturn(true);
         when(featureFlags.isWebEnabled).thenReturn(true);
@@ -413,13 +428,13 @@ plugin3:${pluginUsingOldEmbeddingDir.childDirectory('lib').uri.toString()}
         final Directory webPluginWithNestedFile =
             fs.systemTempDirectory.createTempSync('web_plugin_with_nested');
         webPluginWithNestedFile.childFile('pubspec.yaml').writeAsStringSync('''
-flutter:
+  flutter:
     plugin:
       platforms:
         web:
           pluginClass: WebPlugin
           fileName: src/web_plugin.dart
-''');
+  ''');
         webPluginWithNestedFile
           .childDirectory('lib')
           .childDirectory('src')
@@ -446,11 +461,13 @@ web_plugin_with_nested:${webPluginWithNestedFile.childDirectory('lib').uri.toStr
         FeatureFlags: () => featureFlags,
       });
     });
+  });
 }
 
 class MockAndroidProject extends Mock implements AndroidProject {}
 class MockFeatureFlags extends Mock implements FeatureFlags {}
 class MockFlutterProject extends Mock implements FlutterProject {}
+class MockFile extends Mock implements File {}
 class MockIosProject extends Mock implements IosProject {}
 class MockMacOSProject extends Mock implements MacOSProject {}
 class MockXcodeProjectInterpreter extends Mock implements XcodeProjectInterpreter {}