[all] Omit obvious local types (flutter#10511)

Makes the analysis options changes described in
flutter/flutter#178827:
- Adding
[omit_obvious_local_variable_types](https://dart.dev/tools/linter-rules/omit_obvious_local_variable_types)
- Adding
[specify_nonobvious_local_variable_types](https://dart.dev/tools/linter-rules/specify_nonobvious_local_variable_types)
- Adding
[specify_nonobvious_property_types](https://dart.dev/tools/linter-rules/specify_nonobvious_property_types)
- Adding
[type_annotate_public_apis](https://dart.dev/tools/linter-rules/type_annotate_public_apis)
- Removing
[always_specify_types](https://dart.dev/tools/linter-rules/always_specify_types)

After those changes, makes the following repo-wide changes:
- `dart fix --apply` in all packages and in script/tool/
- `dart format` in all packages and in script/tool/
- `update-excerpts` repo tooling command to update excerpts based on the
changes to their sources

Also updates the min Flutter/Dart SDK version to 3.35/3.9 for the
following packages, to avoid `analyze` failures in the `N-2` legacy
analysis run due to what appears to be a 3.9 change in what the Dart
analyzer continues to be an obvious local type in loop iterations:
- go_router
- google_fonts
- google_identity_services_web
- google_maps_flutter_web
- local_auth_platform_interface
- metrics_center
- multicast_dns
- pigeon
- rfw
- shared_preferences
- two_dimensional_scrollables
- vector_graphics_compiler
- mustache_template
- path_parsing

Because this is causing a significant amount of format churn already, I
took this opportunity to update the repository tooling to a min Dart SDK
of 3.8 (the N-2 stable version, so the earliest version we need the
tooling to support) to pick up the new format style, so the amount of
automated formatter change is higher in script/tool/ than in the
packages.

This does contain two manual changes (other than the repo tooling min
version):
-
flutter@d700b45
changes `dynamic` to `Object?` in a few places where `dynamic` caused
analyzer warnings under the new rule set.
- Updates the repo tooling to ignore `.dart_tool/` when looking for
unexpected local `analysis_options.yaml` files, to fix issues running
the repo tool's `analyze` command locally based on recent changes in
`dart` behavior.

This does not include any CHANGELOG or version updates; even though we
normally version any changes to production code, mass automated changes
like this aren't worth the churn of releasing. This includes changes to
lib/example/main.dart and to README.md excerpts; while the style changes
will be user-visible on pub.dev, it's fine for those changes to wait for
the next release of each package.

Part of flutter/flutter#178827

Author: stuartmorgan-g

analysis_options.yaml

@@ -29,7 +29,7 @@ linter:
     - always_declare_return_types
     - always_put_control_body_on_new_line
     # - always_put_required_named_parameters_first # we prefer having parameters in the same order as fields https://github.com/flutter/flutter/issues/10219
-    - always_specify_types
+    # - always_specify_types # conflicts with omit_obvious_local_variable_types
     # - always_use_package_imports # we do this commonly
     - annotate_overrides
     # - avoid_annotating_with_dynamic # conflicts with always_specify_types
@@ -128,7 +128,8 @@ linter:
     - noop_primitive_operations
     - null_check_on_nullable_type_parameter
     - null_closures
-    # - omit_local_variable_types # opposite of always_specify_types
+    # - omit_local_variable_types # conflicts with specify_nonobvious_local_variable_types
+    - omit_obvious_local_variable_types
     # - one_member_abstracts # too many false positives
     - only_throw_errors # this does get disabled in a few places where we have legacy code that uses strings et al
     - overridden_fields
@@ -187,10 +188,12 @@ linter:
     - sort_constructors_first
     - sort_pub_dependencies # DIFFERENT FROM FLUTTER/FLUTTER: Flutter's use case for not sorting does not apply to this repository.
     - sort_unnamed_constructors_first
+    - specify_nonobvious_local_variable_types
+    - specify_nonobvious_property_types
     - test_types_in_equals
     - throw_in_finally
     - tighten_type_of_initializing_formals
-    # - type_annotate_public_apis # subset of always_specify_types
+    - type_annotate_public_apis
     - type_init_formals
     - type_literal_in_constant_pattern
     - unawaited_futures # DIFFERENT FROM FLUTTER/FLUTTER: It's disabled there for "too many false positives"; that's not an issue here, and missing awaits have caused production issues in plugins.

packages/animations/example/lib/container_transition.dart

@@ -384,7 +384,7 @@ class _ExampleSingleTile extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    const double height = 100.0;
+    const height = 100.0;
 
     return _InkWellOverlay(
       openContainer: openContainer,

packages/animations/example/lib/shared_axis_transition.dart

@@ -152,7 +152,7 @@ class _CourseSwitchState extends State<_CourseSwitch> {
 
   @override
   Widget build(BuildContext context) {
-    final String subtitle = _value ? 'Bundled' : 'Shown Individually';
+    final subtitle = _value ? 'Bundled' : 'Shown Individually';
     return SwitchListTile(
       title: Text(widget.course),
       subtitle: Text(subtitle),

packages/animations/lib/src/open_container.dart

@@ -643,7 +643,7 @@ class _OpenContainerRoute<T> extends ModalRoute<T> {
     required BuildContext navigatorContext,
     bool delayForSourceRoute = false,
   }) {
-    final RenderBox navigator =
+    final navigator =
         Navigator.of(
               navigatorContext,
               rootNavigator: useRootNavigator,
@@ -679,8 +679,7 @@ class _OpenContainerRoute<T> extends ModalRoute<T> {
   Rect _getRect(GlobalKey key, RenderBox ancestor) {
     assert(key.currentContext != null);
     assert(ancestor.hasSize);
-    final RenderBox render =
-        key.currentContext!.findRenderObject()! as RenderBox;
+    final render = key.currentContext!.findRenderObject()! as RenderBox;
     assert(render.hasSize);
     return MatrixUtils.transformRect(
       render.getTransformTo(ancestor),
@@ -689,8 +688,8 @@ class _OpenContainerRoute<T> extends ModalRoute<T> {
   }
 
   bool get _transitionWasInterrupted {
-    bool wasInProgress = false;
-    bool isInProgress = false;
+    var wasInProgress = false;
+    var isInProgress = false;
 
     switch (_currentAnimationStatus) {
       case AnimationStatus.completed:
@@ -884,8 +883,8 @@ class _FlippableTweenSequence<T> extends TweenSequence<T> {
 
   _FlippableTweenSequence<T>? get flipped {
     if (_flipped == null) {
-      final List<TweenSequenceItem<T>> newItems = <TweenSequenceItem<T>>[];
-      for (int i = 0; i < _items.length; i++) {
+      final newItems = <TweenSequenceItem<T>>[];
+      for (var i = 0; i < _items.length; i++) {
         newItems.add(
           TweenSequenceItem<T>(
             tween: _items[i].tween,

packages/animations/lib/src/page_transition_switcher.dart

@@ -293,8 +293,8 @@ class _PageTransitionSwitcherState extends State<PageTransitionSwitcher>
       _activeEntries.forEach(_updateTransitionForEntry);
     }
 
-    final bool hasNewChild = widget.child != null;
-    final bool hasOldChild = _currentEntry != null;
+    final hasNewChild = widget.child != null;
+    final hasOldChild = _currentEntry != null;
     if (hasNewChild != hasOldChild ||
         hasNewChild &&
             !Widget.canUpdate(widget.child!, _currentEntry!.widgetChild)) {
@@ -327,11 +327,11 @@ class _PageTransitionSwitcherState extends State<PageTransitionSwitcher>
     if (widget.child == null) {
       return;
     }
-    final AnimationController primaryController = AnimationController(
+    final primaryController = AnimationController(
       duration: widget.duration,
       vsync: this,
     );
-    final AnimationController secondaryController = AnimationController(
+    final secondaryController = AnimationController(
       duration: widget.duration,
       vsync: this,
     );
@@ -373,7 +373,7 @@ class _PageTransitionSwitcherState extends State<PageTransitionSwitcher>
       primaryController,
       secondaryController,
     );
-    final _ChildEntry entry = _ChildEntry(
+    final entry = _ChildEntry(
       widgetChild: child,
       transition: KeyedSubtree.wrap(transition, _childNumber),
       primaryController: primaryController,

packages/animations/test/dual_transition_builder_test.dart

@@ -7,7 +7,7 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   testWidgets('runs animations', (WidgetTester tester) async {
-    final AnimationController controller = AnimationController(
+    final controller = AnimationController(
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),
     );
@@ -75,7 +75,7 @@ void main() {
   });
 
   testWidgets('keeps state', (WidgetTester tester) async {
-    final AnimationController controller = AnimationController(
+    final controller = AnimationController(
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),
     );
@@ -146,7 +146,7 @@ void main() {
   testWidgets('does not jump when interrupted - forward', (
     WidgetTester tester,
   ) async {
-    final AnimationController controller = AnimationController(
+    final controller = AnimationController(
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),
     );
@@ -212,7 +212,7 @@ void main() {
   testWidgets('does not jump when interrupted - reverse', (
     WidgetTester tester,
   ) async {
-    final AnimationController controller = AnimationController(
+    final controller = AnimationController(
       value: 1.0,
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),

packages/animations/test/fade_scale_transition_test.dart

@@ -361,7 +361,7 @@ void main() {
   });
 
   testWidgets('should preserve state', (WidgetTester tester) async {
-    final AnimationController controller = AnimationController(
+    final controller = AnimationController(
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),
     );
@@ -416,7 +416,7 @@ double _getOpacity(GlobalKey key, WidgetTester tester) {
     matching: find.byType(FadeTransition),
   );
   return tester.widgetList(finder).fold<double>(1.0, (double a, Widget widget) {
-    final FadeTransition transition = widget as FadeTransition;
+    final transition = widget as FadeTransition;
     return a * transition.opacity.value;
   });
 }
@@ -427,7 +427,7 @@ double _getScale(GlobalKey key, WidgetTester tester) {
     matching: find.byType(ScaleTransition),
   );
   return tester.widgetList(finder).fold<double>(1.0, (double a, Widget widget) {
-    final ScaleTransition transition = widget as ScaleTransition;
+    final transition = widget as ScaleTransition;
     return a * transition.scale.value;
   });
 }

packages/animations/test/fade_through_transition_test.dart

@@ -10,12 +10,8 @@ void main() {
   testWidgets(
     'FadeThroughPageTransitionsBuilder builds a FadeThroughTransition',
     (WidgetTester tester) async {
-      final AnimationController animation = AnimationController(
-        vsync: const TestVSync(),
-      );
-      final AnimationController secondaryAnimation = AnimationController(
-        vsync: const TestVSync(),
-      );
+      final animation = AnimationController(vsync: const TestVSync());
+      final secondaryAnimation = AnimationController(vsync: const TestVSync());
 
       await tester.pumpWidget(
         const FadeThroughPageTransitionsBuilder().buildTransitions<void>(
@@ -34,9 +30,9 @@ void main() {
   testWidgets('FadeThroughTransition runs forward', (
     WidgetTester tester,
   ) async {
-    final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
-    const String bottomRoute = '/';
-    const String topRoute = '/a';
+    final navigator = GlobalKey<NavigatorState>();
+    const bottomRoute = '/';
+    const topRoute = '/a';
 
     await tester.pumpWidget(_TestWidget(navigatorKey: navigator));
     expect(find.text(bottomRoute), findsOneWidget);
@@ -116,9 +112,9 @@ void main() {
   testWidgets('FadeThroughTransition runs backwards', (
     WidgetTester tester,
   ) async {
-    final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
-    const String bottomRoute = '/';
-    const String topRoute = '/a';
+    final navigator = GlobalKey<NavigatorState>();
+    const bottomRoute = '/';
+    const topRoute = '/a';
 
     await tester.pumpWidget(_TestWidget(navigatorKey: navigator));
     navigator.currentState!.pushNamed('/a');
@@ -206,9 +202,9 @@ void main() {
   testWidgets('FadeThroughTransition does not jump when interrupted', (
     WidgetTester tester,
   ) async {
-    final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
-    const String bottomRoute = '/';
-    const String topRoute = '/a';
+    final navigator = GlobalKey<NavigatorState>();
+    const bottomRoute = '/';
+    const topRoute = '/a';
 
     await tester.pumpWidget(_TestWidget(navigatorKey: navigator));
     expect(find.text(bottomRoute), findsOneWidget);
@@ -271,9 +267,9 @@ void main() {
   testWidgets('State is not lost when transitioning', (
     WidgetTester tester,
   ) async {
-    final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
-    const String bottomRoute = '/';
-    const String topRoute = '/a';
+    final navigator = GlobalKey<NavigatorState>();
+    const bottomRoute = '/';
+    const topRoute = '/a';
 
     await tester.pumpWidget(
       _TestWidget(
@@ -358,11 +354,11 @@ void main() {
   });
 
   testWidgets('should keep state', (WidgetTester tester) async {
-    final AnimationController animation = AnimationController(
+    final animation = AnimationController(
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),
     );
-    final AnimationController secondaryAnimation = AnimationController(
+    final secondaryAnimation = AnimationController(
       vsync: const TestVSync(),
       duration: const Duration(milliseconds: 300),
     );
@@ -431,7 +427,7 @@ double _getOpacity(String key, WidgetTester tester) {
     matching: find.byType(FadeTransition),
   );
   return tester.widgetList(finder).fold<double>(1.0, (double a, Widget widget) {
-    final FadeTransition transition = widget as FadeTransition;
+    final transition = widget as FadeTransition;
     return a * transition.opacity.value;
   });
 }
@@ -442,7 +438,7 @@ double _getScale(String key, WidgetTester tester) {
     matching: find.byType(ScaleTransition),
   );
   return tester.widgetList(finder).fold<double>(1.0, (double a, Widget widget) {
-    final ScaleTransition transition = widget as ScaleTransition;
+    final transition = widget as ScaleTransition;
     return a * transition.scale.value;
   });
 }

packages/animations/test/modal_test.dart

@@ -430,7 +430,7 @@ void main() {
   testWidgets('showModal builds a new route with specified route settings', (
     WidgetTester tester,
   ) async {
-    const RouteSettings routeSettings = RouteSettings(
+    const routeSettings = RouteSettings(
       name: 'route-name',
       arguments: 'arguments',
     );
@@ -473,7 +473,7 @@ void main() {
   testWidgets('showModal builds a new route with specified image filter', (
     WidgetTester tester,
   ) async {
-    final ui.ImageFilter filter = ui.ImageFilter.blur(sigmaX: 1, sigmaY: 1);
+    final filter = ui.ImageFilter.blur(sigmaX: 1, sigmaY: 1);
 
     final Widget button = Builder(
       builder: (BuildContext context) {
@@ -518,7 +518,7 @@ double _getOpacity(GlobalKey key, WidgetTester tester) {
     matching: find.byType(FadeTransition),
   );
   return tester.widgetList(finder).fold<double>(1.0, (double a, Widget widget) {
-    final FadeTransition transition = widget as FadeTransition;
+    final transition = widget as FadeTransition;
     return a * transition.opacity.value;
   });
 }
@@ -529,7 +529,7 @@ double _getScale(GlobalKey key, WidgetTester tester) {
     matching: find.byType(ScaleTransition),
   );
   return tester.widgetList(finder).fold<double>(1.0, (double a, Widget widget) {
-    final ScaleTransition transition = widget as ScaleTransition;
+    final transition = widget as ScaleTransition;
     return a * transition.scale.value;
   });
 }