bring the packages's lints in-line with the Flutter standard

analysis_options.yaml

@@ -1,19 +1,143 @@
+# Specify analysis options.
+#
+# 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
+#
+# This file contains the analysis options used by Flutter tools, such as IntelliJ,
+# Android Studio, and the `flutter analyze` command.
+
 analyzer:
+  language:
+    enableSuperMixins: true
+  strong-mode:
+    implicit-dynamic: false
   errors:
-    unused_import: error
+    # treat missing required parameters as a warning (not a hint)
+    missing_required_param: warning
+    # treat missing returns as a warning (not a hint)
+    missing_return: warning
 
-#TODO: Normalize this with /flutter/flutter/blob/master/analysis_options.yaml.
 linter:
   rules:
+    # these rules are documented on and in the same order as
+    # the Dart Lint rules page to make maintenance easier
+    # https://github.com/dart-lang/linter/blob/master/example/all.yaml
+    - 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_require_non_null_named_parameters
+    - always_specify_types
+    - annotate_overrides
+    # - avoid_annotating_with_dynamic # conflicts with always_specify_types
+    - avoid_as
+    # - avoid_bool_literals_in_conditional_expressions # not yet tested
+    # - avoid_catches_without_on_clauses # we do this commonly
+    # - avoid_catching_errors # we do this commonly
+    - avoid_classes_with_only_static_members
+    # - avoid_double_and_int_checks # only useful when targeting JS runtime
+    - avoid_empty_else
+    - avoid_field_initializers_in_const_classes
+    - avoid_function_literals_in_foreach_calls
     - avoid_init_to_null
+    # - avoid_js_rounded_ints # only useful when targeting JS runtime
+    - avoid_null_checks_in_equality_operators
+    # - avoid_positional_boolean_parameters # not yet tested
+    # - avoid_private_typedef_functions # we prefer having typedef (discussion in https://github.com/flutter/flutter/pull/16356)
+    - avoid_relative_lib_imports
+    - avoid_renaming_method_parameters
     - avoid_return_types_on_setters
+    # - avoid_returning_null # we do this commonly
+    # - avoid_returning_this # https://github.com/dart-lang/linter/issues/842
+    # - avoid_setters_without_getters # not yet tested
+    # - avoid_single_cascade_in_expression_statements # not yet tested
+    - avoid_slow_async_io
+    # - avoid_types_as_parameter_names # https://github.com/dart-lang/linter/pull/954/files
+    # - avoid_types_on_closure_parameters # conflicts with always_specify_types
+    # - avoid_unused_constructor_parameters # https://github.com/dart-lang/linter/pull/847
+    - await_only_futures
     - camel_case_types
+    - cancel_subscriptions
+    # - cascade_invocations # not yet tested
+    # - close_sinks # https://github.com/flutter/flutter/issues/5789
+    # - comment_references # blocked on https://github.com/dart-lang/dartdoc/issues/1153
+    # - constant_identifier_names # https://github.com/dart-lang/linter/issues/204
+    - control_flow_in_finally
     - directives_ordering
+    - empty_catches
+    - empty_constructor_bodies
+    - empty_statements
     - hash_and_equals
+    - implementation_imports
+    # - invariant_booleans # https://github.com/flutter/flutter/issues/5790
     - iterable_contains_unrelated_type
+    # - join_return_with_assignment # not yet tested
+    - library_names
+    - library_prefixes
     - list_remove_unrelated_type
+    # - literal_only_boolean_expressions # https://github.com/flutter/flutter/issues/5791
+    - no_adjacent_strings_in_list
+    - no_duplicate_case_values
+    - non_constant_identifier_names
+    # - omit_local_variable_types # opposite of always_specify_types
+    # - one_member_abstracts # too many false positives
+    # - only_throw_errors # https://github.com/flutter/flutter/issues/5792
+    - overridden_fields
+    - package_api_docs
+    - package_names
+    - package_prefixed_library_names
+    # - parameter_assignments # we do this commonly
+    - prefer_adjacent_string_concatenation
+    - prefer_asserts_in_initializer_lists
+    - prefer_bool_in_asserts
+    - prefer_collection_literals
+    - prefer_conditional_assignment
+    - prefer_const_constructors
+    - prefer_const_constructors_in_immutables
+    - prefer_const_declarations
+    - prefer_const_literals_to_create_immutables
+    # - prefer_constructors_over_static_methods # not yet tested
+    - prefer_contains
+    - prefer_equal_for_default_values
+    # - 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_final_fields
+    - prefer_final_locals
+    - prefer_foreach
+    # - prefer_function_declarations_over_variables # not yet tested
+    - prefer_initializing_formals
+    # - prefer_interpolation_to_compose_strings # not yet tested
+    # - prefer_iterable_whereType # https://github.com/dart-lang/sdk/issues/32463
+    - prefer_is_empty
+    - prefer_is_not_empty
+    - prefer_single_quotes
+    - prefer_typing_uninitialized_variables
+    - recursive_getters
     - slash_for_doc_comments
+    - sort_constructors_first
+    - sort_unnamed_constructors_first
+    - super_goes_last
     - test_types_in_equals
+    - throw_in_finally
+    # - type_annotate_public_apis # subset of always_specify_types
+    - type_init_formals
+    # - unawaited_futures # https://github.com/flutter/flutter/issues/5793
+    - unnecessary_brace_in_string_interps
+    - unnecessary_const
+    - unnecessary_getters_setters
+    # - unnecessary_lambdas # https://github.com/dart-lang/linter/issues/498
+    - unnecessary_null_aware_assignments
+    - unnecessary_null_in_if_null_operators
+    - unnecessary_overrides
+    - unnecessary_parenthesis
+    - unnecessary_statements
+    - unnecessary_this
     - unrelated_type_equality_checks
+    - use_rethrow_when_possible
+    # - use_setters_to_change_properties # not yet tested
+    # - use_string_buffers # https://github.com/dart-lang/linter/pull/664
+    # - use_to_and_as_if_applicable # has false positives, so we prefer to catch this by code-review
     - valid_regexps
+    # - void_checks # not yet tested

lib/charts/charts.dart

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:async';
-import 'dart:html' show Element, window, Rectangle;
+import 'dart:html' show Element, window, Rectangle, Event;
 import 'dart:math' as math;
 
 import '../framework/framework.dart';
@@ -20,7 +20,7 @@ abstract class LineChart<T> {
   LineChart(this.parent) {
     parent.element.style.position = 'relative';
 
-    window.onResize.listen((e) => _updateSize());
+    window.onResize.listen((Event e) => _updateSize());
     Timer.run(_updateSize);
 
     chartElement = parent.add(div()
@@ -35,14 +35,16 @@ abstract class LineChart<T> {
   }
 
   void _updateSize() {
-    if (!isMounted) return;
+    if (!isMounted) {
+      return;
+    }
 
-    Rectangle rect = chartElement.element.getBoundingClientRect();
+    final Rectangle<num> rect = chartElement.element.getBoundingClientRect();
     if (rect.width == 0 || rect.height == 0) {
       return;
     }
 
-    Element svgChild = chartElement.element.children.first;
+    final Element svgChild = chartElement.element.children.first;
     svgChild.setAttribute('viewBox', '0 0 ${rect.width} ${rect.height}');
     dim = new math.Point<int>(rect.width.toInt(), rect.height.toInt());
 

lib/device/device.dart

@@ -20,7 +20,7 @@ class DeviceScreen extends Screen {
   ExtensionTracker extensionTracker;
 
   CoreElement togglesDiv;
-  Map<String, bool> boolValues = {};
+  Map<String, bool> boolValues = <String, bool>{};
 
   DeviceScreen()
       : super(
@@ -36,17 +36,17 @@ class DeviceScreen extends Screen {
 
   @override
   void createContent(Framework framework, CoreElement mainDiv) {
-    mainDiv.add([
+    mainDiv.add(<CoreElement>[
       div(c: 'section')
-        ..add([
+        ..add(<CoreElement>[
           form()
             ..layoutHorizontal()
-            ..add([
+            ..add(<CoreElement>[
               div()..flex(),
             ])
         ]),
       div(c: 'section')
-        ..add([
+        ..add(<CoreElement>[
           div(text: 'Framework toggles', c: 'title'),
           togglesDiv = div(),
         ])
@@ -79,10 +79,13 @@ class DeviceScreen extends Screen {
     deviceStatus.element.text = '';
   }
 
+  @override
   HelpInfo get helpInfo => null;
 
   void _rebuildTogglesDiv() {
-    if (togglesDiv == null || extensionTracker == null) return;
+    if (togglesDiv == null || extensionTracker == null) {
+      return;
+    }
 
     togglesDiv.clear();
 
@@ -102,7 +105,7 @@ class DeviceScreen extends Screen {
 
     togglesDiv.add(div(c: 'form-checkbox')
       ..add(new CoreElement('label')
-        ..add([
+        ..add(<CoreElement>[
           input = new CoreElement('input')..setAttribute('type', 'checkbox'),
           span(text: rpc),
         ])));
@@ -117,19 +120,21 @@ class DeviceScreen extends Screen {
     }
 
     input.element.onChange.listen((_) {
-      html.InputElement e = input.element;
+      final html.InputElement e = input.element;
       boolValues[rpc] = e.checked;
       extensionTracker.setBoolExtensionMethod(rpc, e.checked);
     });
   }
 }
 
 class ExtensionTracker {
-  final StreamController _changeController = new StreamController.broadcast();
+  final StreamController<Null> _changeController =
+      new StreamController<Null>.broadcast();
 
   VmService service;
 
-  Map<String, Set<IsolateRef>> extensionToIsolatesMap = {};
+  Map<String, Set<IsolateRef>> extensionToIsolatesMap =
+      <String, Set<IsolateRef>>{};
 
   ExtensionTracker(this.service) {
     service.onIsolateEvent.listen((Event e) {
@@ -145,10 +150,10 @@ class ExtensionTracker {
 
   bool get hasConnection => service != null;
 
-  Stream get onChange => _changeController.stream;
+  Stream<Null> get onChange => _changeController.stream;
 
   bool get hasIsolateTargets {
-    for (Set set in extensionToIsolatesMap.values) {
+    for (Set<IsolateRef> set in extensionToIsolatesMap.values) {
       if (set.isNotEmpty) {
         return true;
       }
@@ -162,13 +167,13 @@ class ExtensionTracker {
   void stop() {}
 
   void _register(IsolateRef isolateRef) {
-    service.getIsolate(isolateRef.id).then((result) {
+    service.getIsolate(isolateRef.id).then((dynamic result) {
       if (result is Isolate) {
-        Isolate isolate = result;
+        final Isolate isolate = result;
 
         for (String rpc in isolate.extensionRPCs) {
           if (!extensionToIsolatesMap.containsKey(rpc)) {
-            extensionToIsolatesMap[rpc] = new Set();
+            extensionToIsolatesMap[rpc] = new Set<IsolateRef>();
           }
           extensionToIsolatesMap[rpc].add(isolateRef);
         }
@@ -180,34 +185,36 @@ class ExtensionTracker {
 
   void _registerRpcForIsolate(String rpc, IsolateRef isolateRef) {
     if (!extensionToIsolatesMap.containsKey(rpc)) {
-      extensionToIsolatesMap[rpc] = new Set();
+      extensionToIsolatesMap[rpc] = new Set<IsolateRef>();
     }
     extensionToIsolatesMap[rpc].add(isolateRef);
   }
 
   void _removeIsolate(IsolateRef isolateRef) {
-    for (Set set in extensionToIsolatesMap.values) {
+    for (Set<IsolateRef> set in extensionToIsolatesMap.values) {
       set.remove(isolateRef);
     }
   }
 
   Future<bool> callBoolExtensionMethod(String rpc) {
-    IsolateRef isolateRef = extensionToIsolatesMap[rpc].first;
+    final IsolateRef isolateRef = extensionToIsolatesMap[rpc].first;
     return service
         .callServiceExtension(rpc, isolateId: isolateRef.id)
         .then((Response response) {
       return _convertToBool(response.json['enabled']);
     });
   }
 
-  Future setBoolExtensionMethod(String rpc, bool checked) {
-    IsolateRef isolateRef = extensionToIsolatesMap[rpc].first;
+  Future<Response> setBoolExtensionMethod(String rpc, bool checked) {
+    final IsolateRef isolateRef = extensionToIsolatesMap[rpc].first;
     return service.callServiceExtension(rpc,
-        isolateId: isolateRef.id, args: {'enabled': checked});
+        isolateId: isolateRef.id, args: <String, bool>{'enabled': checked});
   }
 
-  static bool _convertToBool(val) {
-    if (val is bool) return val;
+  static bool _convertToBool(dynamic val) {
+    if (val is bool) {
+      return val;
+    }
     return val.toString() == 'true';
   }
 }