clean-up analysis_options.yaml's across the repository (#81986)

analysis_options.yaml

@@ -11,9 +11,9 @@
 # which should be kept in sync with this file:
 #
 #   - analysis_options.yaml (this file)
-#   - packages/flutter/lib/analysis_options_user.yaml
 #   - https://github.com/flutter/plugins/blob/master/analysis_options.yaml
 #   - https://github.com/flutter/engine/blob/master/analysis_options.yaml
+#   - https://github.com/flutter/packages/blob/master/analysis_options.yaml
 #
 # This file contains the analysis options used by Flutter tools, such as IntelliJ,
 # Android Studio, and the `flutter analyze` command.

dev/integration_tests/web/analysis_options.yaml

-# Exclude lib/main.dart to avoid warnings about the non_nullable
-# experiment before it is enabled.
-analyzer:
-  exclude:
-    - lib/null_safe_main.dart
-    - lib/sound_mode.dart

dev/integration_tests/web/lib/framework_stack_trace.dart

@@ -15,13 +15,13 @@ import 'package:flutter/widgets.dart';
 //
 // See also `dev/integration_tests/web/lib/stack_trace.dart` that tests the
 // framework's ability to parse stack traces in all build modes.
-void main() async {
+Future<void> main() async {
   final StringBuffer errorMessage = StringBuffer();
   debugPrint = (String? message, { int? wrapWidth }) {
     errorMessage.writeln(message);
   };
 
-  runApp(ThrowingWidget());
+  runApp(const ThrowingWidget());
 
   // Let the framework flush error messages.
   await Future<void>.delayed(Duration.zero);
@@ -63,6 +63,8 @@ bool _errorMessageFormattedCorrectly(String errorMessage) {
 }
 
 class ThrowingWidget extends StatefulWidget {
+  const ThrowingWidget({Key? key}) : super(key: key);
+
   @override
   _ThrowingWidgetState createState() => _ThrowingWidgetState();
 }

dev/integration_tests/web/lib/service_worker_test.dart

@@ -5,7 +5,7 @@
 import 'dart:html' as html;
 Future<void> main() async {
   await html.window.navigator.serviceWorker?.ready;
-  final String response = 'CLOSE?version=1';
+  const String response = 'CLOSE?version=1';
   await html.HttpRequest.getString(response);
   html.document.body?.appendHtml(response);
 }

dev/integration_tests/web/lib/sound_mode.dart

@@ -8,7 +8,7 @@ import 'dart:html' as html;
 
 // Verify that web applications can be run in sound mode.
 void main() {
-  const isWeak = <int?>[] is List<int>;
+  const bool isWeak = <int?>[] is List<int>;
   String output;
   if (isWeak) {
     output = '--- TEST FAILED ---';
@@ -19,6 +19,6 @@ void main() {
   html.HttpRequest.request(
     '/test-result',
     method: 'POST',
-    sendData: '$output',
+    sendData: output,
   );
 }

dev/tools/gen_keycodes/analysis_options.yaml

-include: ../../../analysis_options.yaml

packages/flutter/lib/analysis_options_user.yaml

-# Specify analysis options.
+# This file is deprecated and only included in the framework to maintain
+# backwards compatibility. DO NOT MAKE CHANGES TO THIS FILE.
 #
-# Until there are meta linter rules, each desired lint must be explicitly enabled.
-# See: https://github.com/dart-lang/linter/issues/288
-#
-# For a list of lints, see: http://dart-lang.github.io/linter/lints/
-# See the configuration guide for more
-# https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer
-#
-# There are four similar analysis options files in the flutter repos:
-#   - analysis_options.yaml
-#   - packages/flutter/lib/analysis_options_user.yaml (this file)
-#   - https://github.com/flutter/plugins/blob/master/analysis_options.yaml
-#   - https://github.com/flutter/engine/blob/master/analysis_options.yaml
+# The recommended analyzer options for Flutter code (apps, packages, and
+# plugins) outside the Flutter repositories are now defined by
+# package:flutter_lints located at
+# https://github.com/flutter/packages/tree/master/packages/flutter_lints
 #
+# Old documentation:
 # This file contains the analysis options used by "flutter analyze" and the
 # dartanalyzer when analyzing code outside the flutter repository. It isn't named
 # 'analysis_options.yaml' because otherwise editors would use it when analyzing
 # the flutter tool itself.
-#
-# When editing, make sure you keep this and /analysis_options.yaml consistent.
 
 analyzer:
   errors: