Add Dart Code Metrics (#2055)

Author: elliette

dwds/analysis_options.yaml

@@ -22,3 +22,45 @@ linter:
     - require_trailing_commas
     - unawaited_futures
     - unnecessary_lambdas
+
+# TODO(https://github.com/dart-lang/webdev/issues/2053): Enable commented-out rules with fixes.
+dart_code_metrics:
+  metrics:
+    # cyclomatic-complexity: 20
+    # number-of-parameters: 5
+    # maximum-nesting-level: 5
+  metrics-exclude:
+    - test/**
+  rules:
+    - avoid-cascade-after-if-null
+    - avoid-collection-methods-with-unrelated-types
+    - avoid-duplicate-exports
+    # - avoid-global-state  
+    - avoid-missing-enum-constant-in-map
+    - avoid-nested-conditional-expressions
+    - avoid-non-ascii-symbols
+    # - avoid-non-null-assertion
+    # - avoid-passing-async-when-sync-expected
+    - avoid-redundant-async
+    # - avoid-throw-in-catch-block
+    - avoid-unnecessary-type-assertions
+    - avoid-unnecessary-type-casts
+    - avoid-unrelated-type-assertions
+    - avoid-unused-parameters
+    - binary-expression-operand-order
+    - double-literal-format
+    # - format-comment
+    # - member-ordering
+    - no-boolean-literal-compare
+    # - no-empty-block
+    - no-equal-then-else
+    # - prefer-async-await
+    # - prefer-commenting-analyzer-ignores
+    # - prefer-correct-test-file-name
+    - prefer-correct-type-name
+    - prefer-enums-by-name
+    # - prefer-immediate-return
+    - prefer-iterable-of
+    - prefer-last
+    # - prefer-moving-to-variable:
+    #     allow-duplicated-chains: 2

dwds/debug_extension_mv3/tool/build_extension.dart

@@ -74,7 +74,7 @@ Future<int> run({required bool isProd, required bool isMV3}) async {
   return updateExitCode;
 }
 
-Future<int> _handleProcess(Process process) async {
+Future<int> _handleProcess(Process process) {
   _handleOutput(process.stdout, isStdout: true);
   _handleOutput(process.stderr, isStdout: false);
   return process.exitCode;

dwds/debug_extension_mv3/web/background.dart

@@ -62,7 +62,7 @@ void _registerListeners() {
 Future<void> _handleRuntimeMessages(
   dynamic jsRequest,
   MessageSender sender,
-  Function sendResponse,
+  Function _,
 ) async {
   if (jsRequest is! String) return;
 

dwds/debug_extension_mv3/web/cross_extension_communication.dart

@@ -29,7 +29,7 @@ final _eventsForAngularDartDevTools = {
 
 Future<void> handleMessagesFromAngularDartDevTools(
   dynamic jsRequest,
-  MessageSender sender,
+  MessageSender _,
   Function sendResponse,
 ) async {
   if (jsRequest == null) return;
@@ -107,7 +107,8 @@ void _forwardMessageToAngularDartDevTools(ExternalExtensionMessage message) {
   chrome.runtime.sendMessage(
     _angularDartDevToolsId,
     message,
-    /* options */ null,
+    /* options */
+    null,
     allowInterop(([result]) => _checkForErrors(result, message.name)),
   );
 }

dwds/debug_extension_mv3/web/debug_session.dart

@@ -234,9 +234,11 @@ _enableExecutionContextReporting(int tabId) {
       if (chromeError != null) {
         final errorMessage = _translateChromeError(chromeError.message);
         chrome.notifications.create(
-          /*notificationId*/ null,
+          /*notificationId*/
+          null,
           NotificationOptions(message: errorMessage),
-          /*callback*/ null,
+          /*callback*/
+          null,
         );
         return;
       }
@@ -682,7 +684,8 @@ Future<bool> _sendAuthRequest(String authUrl) async {
 Future<bool> _showWarningNotification(String message) {
   final completer = Completer<bool>();
   chrome.notifications.create(
-    /*notificationId*/ null,
+    /*notificationId*/
+    null,
     NotificationOptions(
       title: '[Error] Dart Debug Extension',
       message: message,

dwds/debug_extension_mv3/web/lifeline_connection.dart

@@ -5,7 +5,7 @@
 import 'chrome_api.dart';
 import 'logger.dart';
 
-void main() async {
+void main() {
   _connectToLifelinePort();
 }
 
@@ -15,7 +15,8 @@ void _connectToLifelinePort() {
     prefix: 'Dart Debug Extension',
   );
   chrome.runtime.connect(
-    /*extensionId=*/ null,
+    /*extensionId=*/
+    null,
     ConnectInfo(name: 'keepAlive'),
   );
 }

dwds/debug_extension_mv3/web/messaging.dart

@@ -118,9 +118,11 @@ Future<bool> sendRuntimeMessage({
   );
   final completer = Completer<bool>();
   chrome.runtime.sendMessage(
-    /*id*/ null,
+    /*id*/
+    null,
     message.toJSON(),
-    /*options*/ null,
+    /*options*/
+    null,
     allowInterop(() {
       final error = chrome.runtime.lastError;
       if (error != null) {

dwds/debug_extension_mv3/web/panel.dart

@@ -77,8 +77,8 @@ Future<void> _registerListeners() async {
 
 void _handleRuntimeMessages(
   dynamic jsRequest,
-  MessageSender sender,
-  Function sendResponse,
+  MessageSender _,
+  Function __,
 ) {
   if (jsRequest is! String) return;
 
@@ -120,7 +120,7 @@ void _handleRuntimeMessages(
   );
 }
 
-void _handleStorageChanges(Object storageObj, String storageArea) {
+void _handleStorageChanges(Object storageObj, String _) {
   interceptStorageChange<DebugInfo>(
     storageObj: storageObj,
     expectedType: StorageObject.debugInfo,
@@ -252,7 +252,7 @@ bool _warningBannerIsVisible({String? message}) {
   final warningBanner = document.getElementById(_warningBannerId);
   final isVisible =
       warningBanner != null && warningBanner.classes.contains(_showClass);
-  if (message == null || isVisible == false) return isVisible;
+  if (message == null || !isVisible) return isVisible;
   final warningMsg = document.getElementById(_warningMsgId);
   return warningMsg?.innerHtml == message;
 }
@@ -293,7 +293,7 @@ Future<void> _launchDebugConnection(Event _) async {
 Future<void> _maybeHandleConnectionTimeout() async {
   _connecting = true;
   await Future.delayed(Duration(seconds: 10));
-  if (_connecting == true) {
+  if (_connecting) {
     _handleConnectFailure(ConnectFailureReason.timeout);
   }
 }

dwds/debug_extension_mv3/web/utils.dart

@@ -42,7 +42,7 @@ Future<Tab?> getTab(int tabId) {
   return completer.future;
 }
 
-Future<Tab?> get activeTab async {
+Future<Tab?> get activeTab {
   final completer = Completer<Tab?>();
   final query = QueryInfo(active: true, currentWindow: true);
   chrome.tabs.query(
@@ -96,9 +96,17 @@ void onExtensionIconClicked(void Function(Tab) callback) {
 
 void setExtensionIcon(IconInfo info) {
   if (isMV3) {
-    _setExtensionIconMV3(info, /*callback*/ null);
+    _setExtensionIconMV3(
+      info,
+      /*callback*/
+      null,
+    );
   } else {
-    _setExtensionIconMV2(info, /*callback*/ null);
+    _setExtensionIconMV2(
+      info,
+      /*callback*/
+      null,
+    );
   }
 }
 

dwds/lib/dart_web_debug_service.dart

@@ -141,7 +141,6 @@ class Dwds {
       buildResults,
       devTools,
       assetReader,
-      loadStrategy,
       hostname,
       extensionBackend,
       urlEncoder,

dwds/lib/shared/batched_stream.dart

@@ -66,14 +66,14 @@ class BatchedStreamController<T> {
       if (now > lastSendTime + _batchDelayMilliseconds) {
         lastSendTime = now;
         if (buffer.isNotEmpty) {
-          _outputController.sink.add(List.from(buffer));
+          _outputController.sink.add(List.of(buffer));
           buffer.clear();
         }
       }
     }
 
     if (buffer.isNotEmpty) {
-      _outputController.sink.add(List.from(buffer));
+      _outputController.sink.add(List.of(buffer));
     }
     _completer.complete(true);
   }

dwds/lib/src/debugging/debugger.dart

@@ -222,7 +222,7 @@ class Debugger extends Domain {
   ///
   /// The JS VM is technically not paused at the start of the Isolate so there
   /// will not be a corresponding [DebuggerResumedEvent].
-  Future<void> resumeFromStart() => _resumeHandler(null);
+  void resumeFromStart() => _resumeHandler(null);
 
   /// Notify the debugger the [Isolate] is paused at the application start.
   void notifyPausedAtStart() {
@@ -443,7 +443,6 @@ class Debugger extends Domain {
   }
 
   static bool _isSubRange({
-    required int length,
     int? offset,
     int? count,
   }) {
@@ -552,7 +551,7 @@ class Debugger extends Domain {
       if (_isEmptyRange(offset: offset, count: count, length: length)) {
         return [];
       }
-      if (_isSubRange(offset: offset, count: count, length: length)) {
+      if (_isSubRange(offset: offset, count: count)) {
         final range = await _subRange(
           objectId,
           offset: offset ?? 0,
@@ -743,7 +742,7 @@ class Debugger extends Domain {
   }
 
   /// Handles resume events coming from the Chrome connection.
-  Future<void> _resumeHandler(DebuggerResumedEvent? _) async {
+  void _resumeHandler(DebuggerResumedEvent? _) {
     // We can receive a resume event in the middle of a reload which will result
     // in a null isolate.
     final isolate = inspector.isolate;
@@ -764,7 +763,7 @@ class Debugger extends Domain {
   }
 
   /// Handles targetCrashed events coming from the Chrome connection.
-  Future<void> _crashHandler(TargetCrashedEvent _) async {
+  void _crashHandler(TargetCrashedEvent _) {
     // We can receive a resume event in the middle of a reload which will result
     // in a null isolate.
     final isolate = inspector.isolate;
@@ -947,7 +946,7 @@ class _Breakpoints extends Domain {
 
   /// Adds a breakpoint at [scriptId] and [line] or returns an existing one if
   /// present.
-  Future<Breakpoint> add(String scriptId, int line, int column) async {
+  Future<Breakpoint> add(String scriptId, int line, int column) {
     final id = breakpointIdFor(scriptId, line, column);
     return _bpByDartId.putIfAbsent(
       id,

dwds/lib/src/debugging/inspector.dart

@@ -579,16 +579,13 @@ class AppInspector implements AppInspectorInterface {
   /// Returns the list of scripts refs cached.
   Future<List<ScriptRef>> _populateScriptCaches() async {
     return _scriptCacheMemoizer.runOnce(() async {
-      final libraryUris = [
-        for (var library in isolate.libraries ?? []) library.uri
-      ];
       final scripts = await globalLoadStrategy
           .metadataProviderFor(appConnection.request.entrypointPath)
           .scripts;
       // For all the non-dart: libraries, find their parts and create scriptRefs
       // for them.
       final userLibraries =
-          libraryUris.where((uri) => !uri.startsWith('dart:'));
+          _userLibraryUris(isolate.libraries ?? <LibraryRef>[]);
       for (var uri in userLibraries) {
         final parts = scripts[uri];
         final scriptRefs = [
@@ -619,6 +616,12 @@ class AppInspector implements AppInspectorInterface {
     });
   }
 
+  Iterable<String> _userLibraryUris(Iterable<LibraryRef> libraries) {
+    return libraries
+        .map((library) => library.uri ?? '')
+        .where((uri) => uri.isNotEmpty && !uri.startsWith('dart:'));
+  }
+
   /// Look up the script by id in an isolate.
   @override
   ScriptRef? scriptWithId(String? scriptId) =>

dwds/lib/src/debugging/instance.dart

@@ -121,7 +121,6 @@ class InstanceHelper extends Domain {
     }
 
     final metaData = await ClassMetaData.metaDataFor(
-      inspector.remoteDebugger,
       remoteObject,
       inspector,
     );
@@ -748,7 +747,6 @@ class InstanceHelper extends Domain {
           return _primitiveInstanceRef(InstanceKind.kNull, remoteObject);
         }
         final metaData = await ClassMetaData.metaDataFor(
-          inspector.remoteDebugger,
           remoteObject,
           inspector,
         );

dwds/lib/src/debugging/metadata/class.dart

@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:dwds/src/debugging/remote_debugger.dart';
 import 'package:dwds/src/loaders/strategy.dart';
 import 'package:dwds/src/services/chrome_debug_exception.dart';
 import 'package:dwds/src/utilities/domain.dart';
@@ -128,7 +127,6 @@ class ClassMetaData {
   ///
   /// Returns null if the [remoteObject] is not a Dart class.
   static Future<ClassMetaData?> metaDataFor(
-    RemoteDebugger remoteDebugger,
     RemoteObject remoteObject,
     AppInspectorInterface inspector,
   ) async {

dwds/lib/src/dwds_vm_client.dart

@@ -121,7 +121,7 @@ class DwdsVmClient {
     await client.registerService('ext.dwds.screenshot', 'DWDS');
 
     client.registerServiceCallback('ext.dwds.sendEvent', (event) async {
-      _processSendEvent(event, chromeProxyService, dwdsStats);
+      _processSendEvent(event, dwdsStats);
       return {'result': Success().toJson()};
     });
     await client.registerService('ext.dwds.sendEvent', 'DWDS');
@@ -172,7 +172,6 @@ class DwdsVmClient {
 
 void _processSendEvent(
   Map<String, dynamic> event,
-  ChromeProxyService chromeProxyService,
   DwdsStats dwdsStats,
 ) {
   final type = event['type'] as String?;