Last Engine<>Framework lint sync (#161560)

This is the last time we have to do this because in
https://github.com/flutter/flutter/pull/161554 I am refactoring the
engine's analysis_options.yaml to just import the one from the root of
the repository. When that lands, lints only have to be enabled in one
place to apply across framework and engine.

Before we can do that we have to do one last sync to make sure the
engine code base is ready. This PR implements that last sync and fixing
all lints that came up.

engine/src/flutter/analysis_options.yaml

@@ -1,7 +1,7 @@
 # Specify analysis options.
 #
 # This file is a copy of analysis_options.yaml from flutter repo
-# as of 2023-12-18, but with some modifications marked with
+# as of 2025-01-13, but with some modifications marked with
 # "DIFFERENT FROM FLUTTER/FLUTTER" below.
 
 analyzer:
@@ -36,10 +36,11 @@ linter:
     # - always_specify_types # DIFFERENT FROM FLUTTER/FLUTTER; see https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#dart
     # - always_use_package_imports # we do this commonly
     - annotate_overrides
+    - annotate_redeclares
     # - avoid_annotating_with_dynamic # conflicts with always_specify_types
     - avoid_bool_literals_in_conditional_expressions
     # - avoid_catches_without_on_clauses # blocked on https://github.com/dart-lang/linter/issues/3023
-    # - avoid_catching_errors # blocked on https://github.com/dart-lang/linter/issues/3023
+    # - avoid_catching_errors # blocked on https://github.com/dart-lang/linter/issues/4998
     # - avoid_classes_with_only_static_members # we do this commonly for `abstract final class`es
     - avoid_double_and_int_checks
     - avoid_dynamic_calls
@@ -49,6 +50,7 @@ linter:
     - avoid_field_initializers_in_const_classes
     # - avoid_final_parameters # incompatible with prefer_final_parameters
     - avoid_function_literals_in_foreach_calls
+    # - avoid_futureor_void # not yet tested
     # - avoid_implementing_value_types # see https://github.com/dart-lang/linter/issues/4558
     - avoid_init_to_null
     - avoid_js_rounded_ints
@@ -96,6 +98,7 @@ linter:
     - directives_ordering
     # - discarded_futures # too many false positives, similar to unawaited_futures
     # - do_not_use_environment # there are appropriate times to use the environment, especially in our tests and build logic
+    # - document_ignores # not yet tested
     - empty_catches
     - empty_constructor_bodies
     - empty_statements
@@ -108,6 +111,7 @@ linter:
     - implicit_call_tearoffs
     - implicit_reopen
     - invalid_case_patterns
+    - invalid_runtime_check_with_js_interop_types
     # - join_return_with_assignment # not required by flutter style
     - leading_newlines_in_multiline_strings
     - library_annotations
@@ -134,6 +138,8 @@ linter:
     - null_check_on_nullable_type_parameter
     - null_closures
     # - omit_local_variable_types # opposite of always_specify_types
+    # - omit_obvious_local_variable_types # not yet tested
+    # - omit_obvious_property_types # not yet tested
     # - 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
@@ -152,7 +158,7 @@ linter:
     # - prefer_constructors_over_static_methods # far too many false positives
     - prefer_contains
     # - prefer_double_quotes # opposite of prefer_single_quotes
-    # - prefer_expression_function_bodies # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#consider-using--for-short-functions-and-methods
+    # - prefer_expression_function_bodies # conflicts with ./docs/contributing/Style-guide-for-Flutter-repo.md#consider-using--for-short-functions-and-methods
     - prefer_final_fields
     - prefer_final_in_for_each
     - prefer_final_locals
@@ -165,7 +171,7 @@ linter:
     - prefer_if_null_operators
     - prefer_initializing_formals
     - prefer_inlined_adds
-    # - prefer_int_literals # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#use-double-literals-for-double-constants
+    # - prefer_int_literals # conflicts with ./docs/contributing/Style-guide-for-Flutter-repo.md#use-double-literals-for-double-constants
     - prefer_interpolation_to_compose_strings
     - prefer_is_empty
     - prefer_is_not_empty
@@ -191,6 +197,9 @@ linter:
     - sort_constructors_first
     # - sort_pub_dependencies # prevents separating pinned transitive dependencies
     - sort_unnamed_constructors_first
+    # - specify_nonobvious_local_variable_types # not yet tested
+    # - specify_nonobvious_property_types # not yet tested
+    - strict_top_level_inference
     - test_types_in_equals
     - throw_in_finally
     - tighten_type_of_initializing_formals
@@ -198,6 +207,8 @@ linter:
     - type_init_formals
     - type_literal_in_constant_pattern
     # - unawaited_futures # too many false positives, especially with the way AnimationController works
+    # - unintended_html_in_doc_comment # blocked on https://github.com/dart-lang/linter/issues/5065
+    # - unnecessary_async # not yet tested
     - unnecessary_await_in_return
     - unnecessary_brace_in_string_interps
     - unnecessary_breaks
@@ -208,6 +219,7 @@ linter:
     # - unnecessary_lambdas # has false positives: https://github.com/dart-lang/linter/issues/498
     - unnecessary_late
     - unnecessary_library_directive
+    # - unnecessary_library_name # blocked on https://github.com/dart-lang/dartdoc/issues/3882
     - unnecessary_new
     - unnecessary_null_aware_assignments
     - unnecessary_null_aware_operator_on_extension_on_nullable
@@ -222,8 +234,10 @@ linter:
     - unnecessary_string_interpolations
     - unnecessary_this
     - unnecessary_to_list_in_spreads
+    - unnecessary_underscores
     - unreachable_from_main
     - unrelated_type_equality_checks
+    # - unsafe_variance # not yet tested
     - use_build_context_synchronously
     - use_colored_box
     # - use_decorated_box # leads to bugs: DecoratedBox and Container are not equivalent (Container inserts extra padding)
@@ -243,5 +257,6 @@ linter:
     - use_super_parameters
     - use_test_throws_matchers
     # - use_to_and_as_if_applicable # has false positives, so we prefer to catch this by code-review
+    - use_truncating_division
     - valid_regexps
     - void_checks

engine/src/flutter/lib/web_ui/analysis_options.yaml

@@ -10,6 +10,7 @@ linter:
   rules:
     avoid_print: false
     avoid_setters_without_getters: false
+    invalid_runtime_check_with_js_interop_types: false
     library_private_types_in_public_api: false
     no_default_cases: false
     prefer_relative_imports: false

engine/src/flutter/lib/web_ui/lib/src/engine/initialization.dart

@@ -141,7 +141,7 @@ Future<void> initializeEngineServices({
   //
   // This extension does not need to clean-up Dart statics. Those are cleaned
   // up by the compiler.
-  developer.registerExtension('ext.flutter.disassemble', (_, __) {
+  developer.registerExtension('ext.flutter.disassemble', (_, _) {
     for (final ui.VoidCallback listener in _hotRestartListeners) {
       listener();
     }

engine/src/flutter/lib/web_ui/lib/src/engine/platform_dispatcher/app_lifecycle_state.dart

@@ -104,7 +104,7 @@ class _BrowserAppLifecycleState extends AppLifecycleState {
     }
   });
 
-  void _onViewCountChanged(_) {
+  void _onViewCountChanged(int _) {
     if (_viewManager.views.isEmpty) {
       onAppLifecycleStateChange(ui.AppLifecycleState.detached);
     } else {

engine/src/flutter/lib/web_ui/test/engine/composition_test.dart

@@ -43,7 +43,7 @@ GloballyPositionedTextEditingStrategy _enableEditingStrategy({
 
   owner.debugTextEditingStrategyOverride = editingStrategy;
 
-  editingStrategy.enable(owner.configuration!, onChange: onChange ?? (_, __) {}, onAction: (_) {});
+  editingStrategy.enable(owner.configuration!, onChange: onChange ?? (_, _) {}, onAction: (_) {});
   return editingStrategy;
 }
 

engine/src/flutter/lib/web_ui/test/engine/pointer_binding/event_position_helper_test.dart

@@ -111,7 +111,7 @@ void doTests() {
 
       textEditing.strategy.enable(
         InputConfiguration(viewId: view.viewId),
-        onChange: (_, __) {},
+        onChange: (_, _) {},
         onAction: (_) {},
       );
 

engine/src/flutter/lib/web_ui/test/engine/semantics/text_field_test.dart

@@ -153,7 +153,7 @@ void testMain() {
       int actionCount = 0;
       strategy.enable(
         singlelineConfig,
-        onChange: (_, __) {
+        onChange: (_, _) {
           changeCount++;
         },
         onAction: (_) {
@@ -218,7 +218,7 @@ void testMain() {
     });
 
     test('Does not overwrite text value and selection editing state on semantic updates', () {
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       final textFieldSemantics = createTextFieldSemantics(
         value: 'hello',
@@ -242,7 +242,7 @@ void testMain() {
     test('Updates editing state when receiving framework messages from the text input channel', () {
       expect(owner().semanticsHost.ownerDocument?.activeElement, domDocument.body);
 
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       final textFieldSemantics = createTextFieldSemantics(
         value: 'hello',
@@ -280,7 +280,7 @@ void testMain() {
     test('Gives up focus after DOM blur', () {
       expect(owner().semanticsHost.ownerDocument?.activeElement, domDocument.body);
 
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
       final textFieldSemantics = createTextFieldSemantics(value: 'hello', isFocused: true);
 
       final textField = textFieldSemantics.semanticRole! as SemanticTextField;
@@ -294,7 +294,7 @@ void testMain() {
     });
 
     test('Does not dispose and recreate dom elements in persistent mode', () async {
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       // It doesn't create a new DOM element.
       expect(strategy.domElement, isNull);
@@ -323,7 +323,7 @@ void testMain() {
     });
 
     test('Refocuses when setting editing state', () {
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       createTextFieldSemantics(value: 'hello', isFocused: true);
       expect(strategy.domElement, isNotNull);
@@ -352,7 +352,7 @@ void testMain() {
     });
 
     test('Works in multi-line mode', () {
-      strategy.enable(multilineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(multilineConfig, onChange: (_, _) {}, onAction: (_) {});
       createTextFieldSemantics(value: 'hello', isFocused: true, isMultiline: true);
 
       final textArea = strategy.domElement! as DomHTMLTextAreaElement;
@@ -360,7 +360,7 @@ void testMain() {
 
       expect(owner().semanticsHost.ownerDocument?.activeElement, strategy.domElement);
 
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       textArea.blur();
       expect(owner().semanticsHost.ownerDocument?.activeElement, domDocument.body);
@@ -373,7 +373,7 @@ void testMain() {
     });
 
     test('multi-line and obscured', () {
-      strategy.enable(multilineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(multilineConfig, onChange: (_, _) {}, onAction: (_) {});
       createTextFieldSemantics(
         value: 'hello',
         isFocused: true,
@@ -391,7 +391,7 @@ void testMain() {
     }, skip: ui_web.browser.browserEngine == ui_web.BrowserEngine.firefox);
 
     test('Does not position or size its DOM element', () {
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       // Send width and height that are different from semantics values on
       // purpose.
@@ -450,7 +450,7 @@ void testMain() {
     }
 
     test('Changes focus from one text field to another through a semantics update', () {
-      strategy.enable(singlelineConfig, onChange: (_, __) {}, onAction: (_) {});
+      strategy.enable(singlelineConfig, onChange: (_, _) {}, onAction: (_) {});
 
       // Switch between the two fields a few times.
       for (int i = 0; i < 5; i++) {

engine/src/flutter/lib/web_ui/test/engine/window_test.dart

@@ -279,7 +279,7 @@ Future<void> testMain() async {
     final Zone innerZone = Zone.current.fork();
 
     innerZone.runGuarded(() {
-      void callback(String _, ByteData? __, void Function(ByteData?)? ___) {
+      void callback(String _, ByteData? _, void Function(ByteData?)? _) {
         expect(Zone.current, innerZone);
       }