Enable more lints (#91642)

analysis_options.yaml

@@ -56,10 +56,10 @@ linter:
     - annotate_overrides
     # - avoid_annotating_with_dynamic # conflicts with always_specify_types
     - avoid_bool_literals_in_conditional_expressions
-    # - avoid_catches_without_on_clauses # we do this commonly
-    # - avoid_catching_errors # we do this commonly
+    # - 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_classes_with_only_static_members
-    # - avoid_double_and_int_checks # only useful when targeting JS runtime
+    - avoid_double_and_int_checks
     - avoid_dynamic_calls
     - avoid_empty_else
     - avoid_equals_and_hash_code_on_mutable_classes
@@ -68,7 +68,7 @@ linter:
     - avoid_function_literals_in_foreach_calls
     - avoid_implementing_value_types
     - avoid_init_to_null
-    # - avoid_js_rounded_ints # only useful when targeting JS runtime
+    - avoid_js_rounded_ints
     # - avoid_multiple_declarations_per_line # seems to be a stylistic choice we don't subscribe to
     - avoid_null_checks_in_equality_operators
     # - avoid_positional_boolean_parameters # would have been nice to enable this but by now there's too many places that break it
@@ -81,7 +81,7 @@ linter:
     # - avoid_returning_null # still violated by some pre-nnbd code that we haven't yet migrated
     - avoid_returning_null_for_future
     - avoid_returning_null_for_void
-    # - avoid_returning_this # there are plenty of valid reasons to return this
+    # - avoid_returning_this # there are enough valid reasons to return `this` that this lint ends up with too many false positives
     - avoid_setters_without_getters
     - avoid_shadowing_type_parameters
     - avoid_single_cascade_in_expression_statements
@@ -201,7 +201,7 @@ linter:
     - tighten_type_of_initializing_formals
     # - type_annotate_public_apis # subset of always_specify_types
     - type_init_formals
-    # - unawaited_futures # too many false positives
+    # - unawaited_futures # too many false positives, especially with the way AnimationController works
     - unnecessary_await_in_return
     - unnecessary_brace_in_string_interps
     - unnecessary_const
@@ -216,24 +216,24 @@ linter:
     - unnecessary_nullable_for_final_variable_declarations
     - unnecessary_overrides
     - unnecessary_parenthesis
-    # - unnecessary_raw_strings # not yet tested
+    # - unnecessary_raw_strings # what's "necessary" is a matter of opinion; consistency across strings can help readability more than this lint
     - unnecessary_statements
     - unnecessary_string_escapes
     - unnecessary_string_interpolations
     - unnecessary_this
     - unrelated_type_equality_checks
-    # - unsafe_html # not yet tested
+    - unsafe_html
     - use_build_context_synchronously
     - use_full_hex_values_for_flutter_colors
     - use_function_type_syntax_for_parameters
-    # - use_if_null_to_convert_nulls_to_bools # not yet tested
+    # - use_if_null_to_convert_nulls_to_bools # blocked on https://github.com/dart-lang/sdk/issues/47436
     - use_is_even_rather_than_modulo
     - use_key_in_widget_constructors
     - use_late_for_private_fields_and_variables
     - use_named_constants
     - use_raw_strings
     - use_rethrow_when_possible
-    # - use_setters_to_change_properties # not yet tested
+    - use_setters_to_change_properties
     # - use_string_buffers # has false positives: https://github.com/dart-lang/sdk/issues/34182
     - use_test_throws_matchers
     # - use_to_and_as_if_applicable # has false positives, so we prefer to catch this by code-review

dev/analysis_options.yaml

@@ -2,5 +2,10 @@ include: ../analysis_options.yaml
 
 linter:
   rules:
-    avoid_print: false # We use prints as debugging tools here all the time.
-    only_throw_errors: false # Tests use a less... rigorous style.
+    avoid_print: false # We use prints as debugging tools here a lot.
+
+    # Tests try to throw and catch things in exciting ways all the time, so
+    # we disable these lints for the tests.
+    only_throw_errors: false
+    avoid_catching_errors: false
+    avoid_catches_without_on_clauses: false

dev/bots/analysis_options.yaml

@@ -0,0 +1,5 @@
+include: ../analysis_options.yaml
+
+linter:
+  rules:
+    avoid_js_rounded_ints: false # CLI code doesn't need to worry about JS issues

examples/layers/services/isolate.dart

@@ -46,7 +46,7 @@ class Calculator {
       final List<dynamic> result = decoder.convert(_data) as List<dynamic>;
       final int n = result.length;
       onResultListener('Decoded $n results');
-    } catch (e, stack) {
+    } on FormatException catch (e, stack) {
       debugPrint('Invalid JSON file: $e');
       debugPrint('$stack');
     }

packages/flutter/lib/src/foundation/_bitfield_io.dart

@@ -5,7 +5,7 @@
 import 'bitfield.dart' as bitfield;
 
 /// The dart:io implementation of [bitfield.kMaxUnsignedSMI].
-const int kMaxUnsignedSMI = 0x3FFFFFFFFFFFFFFF;
+const int kMaxUnsignedSMI = 0x3FFFFFFFFFFFFFFF; // ignore: avoid_js_rounded_ints, (VM-only code)
 
 /// The dart:io implementation of [bitfield.Bitfield].
 class BitField<T extends dynamic> implements bitfield.BitField<T> {

packages/flutter/lib/src/foundation/binding.dart

@@ -597,34 +597,27 @@ abstract class BindingBase {
         return Future<void>.delayed(Duration.zero);
       });
 
-      Object? caughtException;
-      StackTrace? caughtStack;
       late Map<String, dynamic> result;
       try {
         result = await callback(parameters);
       } catch (exception, stack) {
-        caughtException = exception;
-        caughtStack = stack;
-      }
-      if (caughtException == null) {
-        result['type'] = '_extensionType';
-        result['method'] = method;
-        return developer.ServiceExtensionResponse.result(json.encode(result));
-      } else {
         FlutterError.reportError(FlutterErrorDetails(
-          exception: caughtException,
-          stack: caughtStack,
+          exception: exception,
+          stack: stack,
           context: ErrorDescription('during a service extension callback for "$method"'),
         ));
         return developer.ServiceExtensionResponse.error(
           developer.ServiceExtensionResponse.extensionError,
           json.encode(<String, String>{
-            'exception': caughtException.toString(),
-            'stack': caughtStack.toString(),
+            'exception': exception.toString(),
+            'stack': stack.toString(),
             'method': method,
           }),
         );
       }
+      result['type'] = '_extensionType';
+      result['method'] = method;
+      return developer.ServiceExtensionResponse.result(json.encode(result));
     });
   }
 

packages/flutter/lib/src/foundation/diagnostics.dart

@@ -2832,6 +2832,8 @@ class DiagnosticsProperty<T> extends DiagnosticsNode {
     try {
       _value = _computeValue!();
     } catch (exception) {
+      // The error is reported to inspector; rethrowing would destroy the
+      // debugging experience.
       _exception = exception;
       _value = null;
     }

packages/flutter/lib/src/rendering/editable.dart

@@ -1091,6 +1091,7 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin,
   /// The prompt rectangle will only be requested on non-web iOS applications.
   ///
   /// When set to null, the currently displayed prompt rectangle (if any) will be dismissed.
+  // ignore: use_setters_to_change_properties, (API predates enforcing the lint)
   void setPromptRectRange(TextRange? newRange) {
     _autocorrectHighlightPainter.highlightedRange = newRange;
   }

packages/flutter/lib/src/rendering/error.dart

@@ -49,7 +49,9 @@ class RenderErrorBox extends RenderBox {
         _paragraph = null;
       }
     } catch (error) {
-      // Intentionally left empty.
+      // If an error happens here we're in a terrible state, so we really should
+      // just forget about it and let the developer deal with the already-reported
+      // errors. It's unlikely that these errors are going to help with that.
     }
   }
 
@@ -161,8 +163,10 @@ class RenderErrorBox extends RenderBox {
         }
         context.canvas.drawParagraph(_paragraph!, offset + Offset(left, top));
       }
-    } catch (e) {
-      // Intentionally left empty.
+    } catch (error) {
+      // If an error happens here we're in a terrible state, so we really should
+      // just forget about it and let the developer deal with the already-reported
+      // errors. It's unlikely that these errors are going to help with that.
     }
   }
 }

packages/flutter/lib/src/rendering/sliver_persistent_header.dart

@@ -640,6 +640,7 @@ abstract class RenderSliverFloatingPersistentHeader extends RenderSliverPersiste
   }
 
   /// Update the last known ScrollDirection when scrolling began.
+  // ignore: use_setters_to_change_properties, (API predates enforcing the lint)
   void updateScrollStartDirection(ScrollDirection direction) {
     _lastStartedScrollDirection = direction;
   }

packages/flutter/lib/src/services/binding.dart

@@ -319,6 +319,7 @@ mixin ServicesBinding on BindingBase, SchedulerBinding {
   ///
   ///   * [SystemChrome.setEnabledSystemUIMode], which specifies the
   ///     [SystemUiMode] to have visible when the application is running.
+  // ignore: use_setters_to_change_properties, (API predates enforcing the lint)
   void setSystemUiChangeCallback(SystemUiChangeCallback? callback) {
     _systemUiChangeCallback = callback;
   }
@@ -387,7 +388,6 @@ class _DefaultBinaryMessenger extends BinaryMessenger {
         try {
           response = await handler(data);
         } catch (exception, stack) {
-
           FlutterError.reportError(FlutterErrorDetails(
             exception: exception,
             stack: stack,

packages/flutter/lib/src/services/message_codecs.dart

@@ -376,7 +376,7 @@ class StandardMessageCodec implements MessageCodec<Object?> {
                                    // decoding because we use tags to detect the type of value.
       buffer.putUint8(_valueFloat64);
       buffer.putFloat64(value);
-    } else if (value is int) {
+    } else if (value is int) { // ignore: avoid_double_and_int_checks, JS code always goes through the `double` path above
       if (-0x7fffffff - 1 <= value && value <= 0x7fffffff) {
         buffer.putUint8(_valueInt32);
         buffer.putInt32(value);

packages/flutter/lib/src/services/platform_channel.dart

@@ -410,8 +410,8 @@ class MethodChannel {
       );
     } on MissingPluginException {
       return null;
-    } catch (e) {
-      return codec.encodeErrorEnvelope(code: 'error', message: e.toString());
+    } catch (error) {
+      return codec.encodeErrorEnvelope(code: 'error', message: error.toString());
     }
   }
 

packages/flutter/lib/src/services/restoration.dart

@@ -1006,7 +1006,9 @@ bool debugIsSerializableForRestoration(Object? object) {
     try {
       const StandardMessageCodec().encodeMessage(object);
       result = true;
-    } catch (_) {
+    } catch (error) {
+      // This is only used in asserts, so reporting the exception isn't
+      // particularly useful, since the assert itself will likely fail.
       result = false;
     }
     return true;

packages/flutter/lib/src/widgets/actions.dart

@@ -160,6 +160,7 @@ abstract class Action<T extends Intent> with Diagnosticable {
   final ObserverList<ActionListenerCallback> _listeners = ObserverList<ActionListenerCallback>();
 
   Action<T>? _currentCallingAction;
+  // ignore: use_setters_to_change_properties, (code predates enabling of this lint)
   void _updateCallingAction(Action<T>? value) {
     _currentCallingAction = value;
   }

packages/flutter/lib/src/widgets/editable_text.dart

@@ -2342,6 +2342,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
   }
 
   Rect? _currentCaretRect;
+  // ignore: use_setters_to_change_properties, (this is used as a callback, can't be a setter)
   void _handleCaretChanged(Rect caretRect) {
     _currentCaretRect = caretRect;
   }

packages/flutter/lib/src/widgets/form.dart

@@ -421,6 +421,7 @@ class FormFieldState<T> extends State<FormField<T>> with RestorationMixin {
   /// the value should be set by a call to [didChange], which ensures that
   /// `setState` is called.
   @protected
+  // ignore: use_setters_to_change_properties, (API predates enforcing the lint)
   void setValue(T? value) {
     _value = value;
   }

packages/flutter/lib/src/widgets/framework.dart

@@ -4453,8 +4453,10 @@ class ErrorWidget extends LeafRenderObjectWidget {
   static String _stringify(Object? exception) {
     try {
       return exception.toString();
-    } catch (e) {
-      // intentionally left empty.
+    } catch (error) {
+      // If we get here, it means things have really gone off the rails, and we're better
+      // off just returning a simple string and letting the developer find out what the
+      // root cause of all their problems are by looking at the console logs.
     }
     return 'Error';
   }
@@ -5426,6 +5428,9 @@ abstract class RenderObjectElement extends Element {
       if (badAncestors.isNotEmpty) {
         badAncestors.insert(0, result);
         try {
+          // We explicitly throw here (even though we immediately redirect the
+          // exception elsewhere) so that debuggers will notice it when they
+          // have "break on exception" enabled.
           throw FlutterError.fromParts(<DiagnosticsNode>[
             ErrorSummary('Incorrect use of ParentDataWidget.'),
             ErrorDescription('The following ParentDataWidgets are providing parent data to the same RenderObject:'),
@@ -5763,9 +5768,10 @@ abstract class RenderObjectElement extends Element {
           ]);
         }
       } on FlutterError catch (e) {
-        // Catching the exception directly to avoid activating the ErrorWidget.
-        // Since the tree is in a broken state, adding the ErrorWidget would
-        // cause more exceptions.
+        // We catch the exception directly to avoid activating the ErrorWidget,
+        // while still allowing debuggers to break on exception. Since the tree
+        // is in a broken state, adding the ErrorWidget would likely cause more
+        // exceptions, which is not good for the debugging experience.
         _debugReportException(ErrorSummary('while applying parent data.'), e, e.stackTrace);
       }
       return true;
@@ -6036,6 +6042,7 @@ abstract class RootRenderObjectElement extends RenderObjectElement {
   /// to [runApp]. The binding is responsible for driving the build pipeline by
   /// calling the build owner's [BuildOwner.buildScope] method. See
   /// [WidgetsBinding.drawFrame].
+  // ignore: use_setters_to_change_properties, (API predates enforcing the lint)
   void assignOwner(BuildOwner owner) {
     _owner = owner;
   }

packages/flutter/lib/src/widgets/navigator.dart

@@ -175,6 +175,7 @@ abstract class Route<T> {
     }
   }
 
+  // ignore: use_setters_to_change_properties, (setters can't be private)
   void _updateRestorationId(String? restorationId) {
     _restorationScopeId.value = restorationId;
   }

packages/flutter/lib/src/widgets/scroll_position.dart

@@ -320,6 +320,7 @@ abstract class ScrollPosition extends ViewportOffset with ScrollMetrics {
   ///    middle of layout and applying the new position immediately.
   ///  * [animateTo], which is like [jumpTo] but animating to the
   ///    destination offset.
+  // ignore: use_setters_to_change_properties, (API is intended to discourage setting value)
   void correctPixels(double value) {
     _pixels = value;
   }

packages/flutter/lib/src/widgets/scrollbar.dart

@@ -1277,7 +1277,10 @@ class RawScrollbarState<T extends RawScrollbar> extends State<T> with TickerProv
     assert (() {
       try {
         scrollController!.position;
-      } catch (_) {
+      } catch (error) {
+        if (scrollController == null || scrollController.positions.length <= 1) {
+          rethrow;
+        }
         throw FlutterError.fromParts(<DiagnosticsNode>[
           ErrorSummary(
             'The $controllerForError is currently attached to more than one '

packages/flutter/lib/src/widgets/sliver.dart

@@ -204,6 +204,7 @@ abstract class SliverChildDelegate {
       if (children != null)
         description.add('estimated child count: $children');
     } catch (e) {
+      // The exception is forwarded to widget inspector.
       description.add('estimated child count: EXCEPTION (${e.runtimeType})');
     }
   }

packages/flutter/lib/src/widgets/text_selection.dart

@@ -1587,7 +1587,13 @@ class ClipboardStatusNotifier extends ValueNotifier<ClipboardStatus> with Widget
     final bool hasStrings;
     try {
       hasStrings = await Clipboard.hasStrings();
-    } catch (stacktrace) {
+    } catch (exception, stack) {
+      FlutterError.reportError(FlutterErrorDetails(
+        exception: exception,
+        stack: stack,
+        library: 'widget library',
+        context: ErrorDescription('while checking if the clipboard has strings'),
+      ));
       // In the case of an error from the Clipboard API, set the value to
       // unknown so that it will try to update again later.
       if (_disposed || value == ClipboardStatus.unknown) {

packages/flutter/lib/src/widgets/widget_inspector.dart

@@ -1962,6 +1962,8 @@ mixin WidgetInspectorService {
         FlutterErrorDetails(
           exception: exception,
           stack: stack,
+          library: 'widget inspector library',
+          context: ErrorDescription('while tracking widget repaints'),
         ),
       );
     }

packages/flutter/test/analysis_options.yaml

@@ -2,4 +2,8 @@ include: ../analysis_options.yaml
 
 linter:
   rules:
-    only_throw_errors: false # We are more flexible for tests.
+    # Tests try to throw and catch things in exciting ways all the time, so
+    # we disable these lints for the tests.
+    only_throw_errors: false
+    avoid_catches_without_on_clauses: false
+    avoid_catching_errors: false

packages/flutter/test/services/message_codecs_vm_test.dart

@@ -18,7 +18,7 @@ void main() {
       checkEncodeDecode<dynamic>(json, -9223372036854775807);
     });
     test('should encode and decode list with a big number', () {
-      final List<dynamic> message = <dynamic>[-7000000000000000007];
+      final List<dynamic> message = <dynamic>[-7000000000000000007]; // ignore: avoid_js_rounded_ints, since we check for round-tripping, the actual value doesn't matter!
       checkEncodeDecode<dynamic>(json, message);
     });
   });
@@ -72,7 +72,7 @@ void main() {
     });
     test('should encode and decode a list containing big numbers', () {
       final List<dynamic> message = <dynamic>[
-        -7000000000000000007,
+        -7000000000000000007, // ignore: avoid_js_rounded_ints, browsers are skipped below
         Int64List.fromList(<int>[-0x7fffffffffffffff - 1, 0, 0x7fffffffffffffff]),
       ];
       checkEncodeDecode<dynamic>(standard, message);

packages/flutter_driver/lib/src/driver/vmservice_driver.dart

@@ -564,6 +564,8 @@ Future<vms.VmService> _waitAndConnect(String url, Map<String, dynamic>? headers)
       await service.getVersion();
       return service;
     } catch (e) {
+      // We should not be catching all errors arbitrarily here, this might hide real errors.
+      // TODO(ianh): Determine which exceptions to catch here.
       await socket?.close();
       if (attempts > 5) {
         _log('It is taking an unusually long time to connect to the VM...');

packages/flutter_driver/lib/src/driver/web_driver.dart

@@ -115,9 +115,10 @@ class WebFlutterDriver extends FlutterDriver {
       response = data != null ? (json.decode(data as String) as Map<String, dynamic>?)! : <String, dynamic>{};
       _logCommunication('<<< $response');
     } catch (error, stackTrace) {
-      throw DriverError("Failed to respond to $command due to remote error\n : \$flutterDriver('${jsonEncode(serialized)}')",
-          error,
-          stackTrace
+      throw DriverError(
+        "Failed to respond to $command due to remote error\n : \$flutterDriver('${jsonEncode(serialized)}')",
+        error,
+        stackTrace
       );
     }
     if (response['isError'] == true)
@@ -261,8 +262,10 @@ class FlutterWebConnection {
     dynamic result;
     try {
       await _driver.execute(script, <void>[]);
-    } catch (_) {
-      // In case there is an exception, do nothing
+    } catch (error) {
+      // We should not just arbitrarily throw all exceptions on the ground.
+      // This is probably hiding real errors.
+      // TODO(ianh): Determine what exceptions are expected here and handle those specifically.
     }
 
     try {
@@ -271,7 +274,10 @@ class FlutterWebConnection {
         matcher: isNotNull,
         timeout: duration ?? const Duration(days: 30),
       );
-    } catch (_) {
+    } catch (error) {
+      // We should not just arbitrarily throw all exceptions on the ground.
+      // This is probably hiding real errors.
+      // TODO(ianh): Determine what exceptions are expected here and handle those specifically.
       // Returns null if exception thrown.
       return null;
     } finally {

packages/flutter_goldens_client/lib/skia_client.dart

@@ -329,15 +329,9 @@ class SkiaGoldClient {
       final Uri requestForImage = Uri.parse(
         'https://flutter-gold.skia.org/img/images/$imageHash.png',
       );
-
-      try {
-        final io.HttpClientRequest request = await httpClient.getUrl(requestForImage);
-        final io.HttpClientResponse response = await request.close();
-        await response.forEach((List<int> bytes) => imageBytes.addAll(bytes));
-
-      } catch(e) {
-        rethrow;
-      }
+      final io.HttpClientRequest request = await httpClient.getUrl(requestForImage);
+      final io.HttpClientResponse response = await request.close();
+      await response.forEach((List<int> bytes) => imageBytes.addAll(bytes));
     },
       SkiaGoldHttpOverrides(),
     );

packages/flutter_test/lib/src/binding.dart

@@ -743,8 +743,10 @@ abstract class TestWidgetsFlutterBinding extends BindingBase
       DiagnosticsNode treeDump;
       try {
         treeDump = renderViewElement?.toDiagnosticsNode() ?? DiagnosticsNode.message('<no tree>');
-        // TODO(jacobr): this is a hack to make sure the tree can safely be fully dumped.
-        // Potentially everything is good enough without this case.
+        // We try to stringify the tree dump here (though we immediately discard the result) because
+        // we want to make sure that if it can't be serialised, we replace it with a message that
+        // says the tree could not be serialised. Otherwise, the real exception might get obscured
+        // by side-effects of the underlying issues causing the tree dumping code to flail.
         treeDump.toStringDeep();
       } catch (exception) {
         treeDump = DiagnosticsNode.message('<additional error caught while dumping tree: $exception>', level: DiagnosticLevel.error);

packages/flutter_test/test/analysis_options.yaml

@@ -0,0 +1,7 @@
+include: ../../analysis_options.yaml
+
+linter:
+  rules:
+    # Tests try to catch errors all the time, so we don't worry about these lints for tests:
+    avoid_catches_without_on_clauses: false
+    avoid_catching_errors: false

packages/flutter_tools/analysis_options.yaml

@@ -3,6 +3,7 @@ include: ../analysis_options.yaml
 linter:
   rules:
     avoid_catches_without_on_clauses: true
+    avoid_catching_errors: false # TODO(ianh): we should refactor the tool codebase to avoid relying on this so much
     curly_braces_in_flow_control_structures: true
     library_private_types_in_public_api: false # Tool does not have any public API.
     no_runtimeType_toString: false # We use runtimeType for debugging in the tool.

packages/flutter_tools/lib/runner.dart

@@ -70,12 +70,11 @@ Future<int> run(
         // We already hit some error, so don't return success.  The error path
         // (which should be in progress) is responsible for calling _exit().
         return 1;
-      // This catches all exceptions to send to crash logging, etc.
-      } catch (error, stackTrace) {  // ignore: avoid_catches_without_on_clauses
+      } catch (error, stackTrace) { // ignore: avoid_catches_without_on_clauses
+        // This catches all exceptions to send to crash logging, etc.
         firstError = error;
         firstStackTrace = stackTrace;
-        return _handleToolError(
-            error, stackTrace, verbose, args, reportCrashes, getVersion);
+        return _handleToolError(error, stackTrace, verbose, args, reportCrashes, getVersion);
       }
     }, onError: (Object error, StackTrace stackTrace) async { // ignore: deprecated_member_use
       // If sending a crash report throws an error into the zone, we don't want
@@ -164,7 +163,8 @@ Future<int> _handleToolError(
     } catch (error) { // ignore: avoid_catches_without_on_clauses
       globals.stdio.stderrWrite(
         'Unable to generate crash report due to secondary error: $error\n'
-        '${globals.userMessages.flutterToolBugInstructions}\n');
+        '${globals.userMessages.flutterToolBugInstructions}\n',
+      );
       // Any exception thrown here (including one thrown by `_exit()`) will
       // get caught by our zone's `onError` handler. In order to avoid an
       // infinite error loop, we throw an error that is recognized above

packages/flutter_tools/lib/src/base/async_guard.dart

@@ -114,7 +114,7 @@ Future<T> asyncGuard<T>(
       }
     // This catches all exceptions so that they can be propagated to the
     // caller-supplied error handling or the completer.
-    } catch (e, s) { // ignore: avoid_catches_without_on_clauses
+    } catch (e, s) { // ignore: avoid_catches_without_on_clauses, forwards to Future
       handleError(e, s);
     }
   }, onError: (Object e, StackTrace s) { // ignore: deprecated_member_use

packages/flutter_tools/lib/src/base/error_handling_io.dart

@@ -348,7 +348,7 @@ class ErrorHandlingFile
           sink.writeFromSync(buffer, 0, chunkLength);
           bytes += chunkLength;
         }
-      } catch (err) { // ignore: avoid_catches_without_on_clauses
+      } catch (err) { // ignore: avoid_catches_without_on_clauses, rethrows
         ErrorHandlingFileSystem.deleteIfExists(resultFile, recursive: true);
         rethrow;
       } finally {

packages/flutter_tools/lib/src/base/task_queue.dart

@@ -89,7 +89,7 @@ class _TaskQueueItem<T> {
   Future<void> run() async {
     try {
       _completer.complete(await _closure());
-    } catch (e) { // ignore: avoid_catches_without_on_clauses
+    } catch (e) { // ignore: avoid_catches_without_on_clauses, forwards to Future
       _completer.completeError(e);
     } finally {
       onComplete?.call();

packages/flutter_web_plugins/lib/src/navigation/utils.dart

@@ -11,7 +11,7 @@ final AnchorElement _urlParsingNode = AnchorElement();
 /// Example: for the url `http://example.com/foo`, the extracted pathname will
 /// be `/foo`.
 String extractPathname(String url) {
-  _urlParsingNode.href = url;
+  _urlParsingNode.href = url; // ignore: unsafe_html, node is never exposed to the user
   final String pathname = _urlParsingNode.pathname ?? '';
   return (pathname.isEmpty || pathname[0] == '/') ? pathname : '/$pathname';
 }

packages/fuchsia_remote_debug_protocol/lib/src/dart/dart_vm.dart

@@ -54,6 +54,8 @@ Future<vms.VmService> _waitAndConnect(
       await service.getVersion();
       return service;
     } catch (e) {
+      // We should not be catching all errors arbitrarily here, this might hide real errors.
+      // TODO(ianh): Determine which exceptions to catch here.
       await socket.close();
       if (attempts > 5) {
         _log.warning('It is taking an unusually long time to connect to the VM...');

packages/fuchsia_remote_debug_protocol/lib/src/fuchsia_remote_connection.dart

@@ -679,14 +679,13 @@ class _SshPortForwarder implements PortForwarder {
   /// If successful returns a valid [ServerSocket] (which must be disconnected
   /// later).
   static Future<ServerSocket?> _createLocalSocket() async {
-    ServerSocket s;
     try {
-      s = await ServerSocket.bind(_ipv4Loopback, 0);
+      return await ServerSocket.bind(_ipv4Loopback, 0);
     } catch (e) {
-      // Failures are signaled by a return value of 0 from this function.
+      // We should not be catching all errors arbitrarily here, this might hide real errors.
+      // TODO(ianh): Determine which exceptions to catch here.
       _log.warning('_createLocalSocket failed: $e');
       return null;
     }
-    return s;
   }
 }

packages/integration_test/lib/_callback_web.dart

@@ -65,8 +65,7 @@ class WebCallbackManager implements CallbackManager {
             'driver side');
       }
     } catch (exception) {
-      throw Exception('Web Driver Command failed: ${command.type} with '
-          'exception $exception');
+      throw Exception('Web Driver Command failed: ${command.type} with exception $exception');
     } finally {
       // Reset the completer.
       _driverCommandComplete = Completer<bool>();

packages/integration_test/lib/_extension_web.dart

@@ -16,10 +16,8 @@ import 'dart:js_util' as js_util;
 /// See also:
 ///
 ///  * `_extension_io.dart`, which has the dart:io implementation
-void registerWebServiceExtension(
-    Future<Map<String, dynamic>> Function(Map<String, String>) callback) {
-  js_util.setProperty(html.window, r'$flutterDriver',
-      allowInterop((dynamic message) async {
+void registerWebServiceExtension(Future<Map<String, dynamic>> Function(Map<String, String>) callback) {
+  js_util.setProperty(html.window, r'$flutterDriver', allowInterop((dynamic message) async {
     try {
       final Map<String, dynamic> messageJson = jsonDecode(message as String) as Map<String, dynamic>;
       final Map<String, String> params = messageJson.cast<String, String>();
@@ -27,9 +25,7 @@ void registerWebServiceExtension(
       context[r'$flutterDriverResult'] = json.encode(result);
     } catch (error, stackTrace) {
       // Encode the error in the same format the FlutterDriver extension uses.
-      //
-      // See:
-      //   * packages\flutter_driver\lib\src\extension\extension.dart
+      // See //packages/flutter_driver/lib/src/extension/extension.dart
       context[r'$flutterDriverResult'] = json.encode(<String, dynamic>{
         'isError': true,
         'response': '$error\n$stackTrace',

packages/integration_test/lib/integration_test_driver_extended.dart

@@ -106,8 +106,10 @@ Future<void> integrationDriver(
       try {
         ok = await onScreenshot(screenshotName, screenshotBytes.cast<int>());
       } catch (exception) {
-        throw StateError('Screenshot failure:\n'
-            'onScreenshot("$screenshotName", <bytes>) threw an exception: $exception');
+        throw StateError(
+          'Screenshot failure:\n'
+          'onScreenshot("$screenshotName", <bytes>) threw an exception: $exception',
+        );
       }
       if (!ok) {
         failures.add(screenshotName);