Migrate some dwds files to null safety

dwds/CHANGELOG.md

@@ -1,3 +1,6 @@
+## 14.0.4-dev
+- Port some `dwds` files to null safety.
+
 ## 14.0.3
 - Make data types null safe.
 - Update `package:vm_service` to 8.3.0.

dwds/lib/asset_reader.dart

@@ -0,0 +1,5 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+export 'src/readers/asset_reader.dart' show AssetReader, UrlEncoder;

dwds/lib/dwds.dart

@@ -40,12 +40,12 @@ export 'src/loaders/frontend_server_require.dart'
 export 'src/loaders/legacy.dart' show LegacyStrategy;
 export 'src/loaders/require.dart' show RequireStrategy;
 export 'src/loaders/strategy.dart' show LoadStrategy, ReloadConfiguration;
-export 'src/readers/asset_reader.dart' show AssetReader;
+export 'src/readers/asset_reader.dart' show AssetReader, UrlEncoder;
 export 'src/readers/frontend_server_asset_reader.dart'
     show FrontendServerAssetReader;
 export 'src/readers/proxy_server_asset_reader.dart' show ProxyServerAssetReader;
 export 'src/servers/devtools.dart';
-export 'src/services/chrome_proxy_service.dart' show ChromeDebugException;
+export 'src/services/chrome_debug_exception.dart' show ChromeDebugException;
 export 'src/services/expression_compiler.dart'
     show ExpressionCompilationResult, ExpressionCompiler, ModuleInfo;
 export 'src/services/expression_compiler_service.dart'
@@ -54,7 +54,6 @@ export 'src/utilities/sdk_configuration.dart'
     show SdkConfiguration, SdkConfigurationProvider;
 
 typedef ConnectionProvider = Future<ChromeConnection> Function();
-typedef UrlEncoder = Future<String> Function(String url);
 
 /// The Dart Web Debug Service.
 class Dwds {

dwds/lib/expression_compiler.dart

@@ -0,0 +1,6 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+export 'src/services/expression_compiler.dart'
+    show ExpressionCompilationResult, ExpressionCompiler, ModuleInfo;

dwds/lib/src/debugging/debugger.dart

@@ -16,6 +16,7 @@ import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart'
 
 import '../loaders/strategy.dart';
 import '../services/chrome_proxy_service.dart';
+import '../services/chrome_debug_exception.dart';
 import '../utilities/conversions.dart';
 import '../utilities/dart_uri.dart';
 import '../utilities/domain.dart';

dwds/lib/src/debugging/execution_context.dart

@@ -2,8 +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.
 
-// @dart = 2.9
-
 import 'dart:async';
 
 import 'package:async/async.dart';
@@ -21,14 +19,17 @@ class RemoteDebuggerExecutionContext extends ExecutionContext {
   final RemoteDebugger _remoteDebugger;
   final _logger = Logger('RemoteDebuggerExecutionContext');
 
-  // Contexts that may contain a Dart application.
-  StreamQueue<int> _contexts;
+  /// Contexts that may contain a Dart application.
+  ///
+  /// Context can be null if an error has occured and we cannot detect
+  /// and parse the context ID.
+  late StreamQueue<int> _contexts;
 
-  int _id;
+  int? _id;
 
   @override
   Future<int> get id async {
-    if (_id != null) return _id;
+    if (_id != null) return _id!;
     _logger.fine('Looking for Dart execution context...');
     const timeoutInMs = 100;
     while (await _contexts.hasNext
@@ -45,7 +46,7 @@ class RemoteDebuggerExecutionContext extends ExecutionContext {
           'expression': r'window["$dartAppInstanceId"];',
           'contextId': context,
         });
-        if (result.result['result']['value'] != null) {
+        if (result.result?['result']?['value'] != null) {
           _logger.fine('Found valid execution context: $context');
           _id = context;
           break;
@@ -59,18 +60,30 @@ class RemoteDebuggerExecutionContext extends ExecutionContext {
     if (_id == null) {
       throw StateError('No context with the running Dart application.');
     }
-    return _id;
+    return _id!;
   }
 
   RemoteDebuggerExecutionContext(this._id, this._remoteDebugger) {
     final contextController = StreamController<int>();
     _remoteDebugger
         .eventStream('Runtime.executionContextsCleared', (e) => e)
         .listen((_) => _id = null);
-    _remoteDebugger
-        .eventStream('Runtime.executionContextCreated',
-            (e) => int.parse(e.params['context']['id'].toString()))
-        .listen(contextController.add);
+    _remoteDebugger.eventStream('Runtime.executionContextCreated', (e) {
+      // Parse and add the context ID to the stream.
+      // If we cannot detect or parse the context ID, add `null` to the stream
+      // to indicate an error context - those will be skipped when trying to find
+      // the dart context, with a warning.
+      final id = e.params?['context']?['id']?.toString();
+      final parsedId = id == null ? null : int.parse(id);
+      if (id == null) {
+        _logger.warning('Cannot find execution context id: $e');
+      } else if (parsedId == null) {
+        _logger.warning('Cannot parse execution context id: $id');
+      }
+      return parsedId;
+    }).listen((e) {
+      if (e != null) contextController.add(e);
+    });
     _contexts = StreamQueue(contextController.stream);
   }
 }

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

@@ -11,7 +11,7 @@ import '../../debugging/classes.dart';
 import '../../debugging/inspector.dart';
 import '../../debugging/remote_debugger.dart';
 import '../../loaders/strategy.dart';
-import '../../services/chrome_proxy_service.dart';
+import '../../services/chrome_debug_exception.dart';
 
 /// Meta data for a remote Dart class in Chrome.
 class ClassMetaData {

dwds/lib/src/debugging/remote_debugger.dart

@@ -2,8 +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.
 
-// @dart = 2.9
-
 import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart';
 
 class TargetCrashedEvent extends WipEvent {
@@ -31,7 +29,7 @@ abstract class RemoteDebugger {
   Stream<void> get onClose;
 
   Future<WipResponse> sendCommand(String command,
-      {Map<String, dynamic> params});
+      {Map<String, dynamic>? params});
 
   Future<void> disable();
 
@@ -47,18 +45,18 @@ abstract class RemoteDebugger {
 
   Future<WipResponse> removeBreakpoint(String breakpointId);
 
-  Future<WipResponse> stepInto({Map<String, dynamic> params});
+  Future<WipResponse> stepInto({Map<String, dynamic>? params});
 
   Future<WipResponse> stepOut();
 
-  Future<WipResponse> stepOver({Map<String, dynamic> params});
+  Future<WipResponse> stepOver({Map<String, dynamic>? params});
 
   Future<WipResponse> enablePage();
 
   Future<WipResponse> pageReload();
 
   Future<RemoteObject> evaluate(String expression,
-      {bool returnByValue, int contextId});
+      {bool? returnByValue, int? contextId});
 
   Future<RemoteObject> evaluateOnCallFrame(
       String callFrameId, String expression);

dwds/lib/src/debugging/webkit_debugger.dart

@@ -2,8 +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.
 
-// @dart = 2.9
-
 import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart';
 
 import 'remote_debugger.dart';
@@ -15,7 +13,7 @@ class WebkitDebugger implements RemoteDebugger {
   /// Null until [close] is called.
   ///
   /// All subsequent calls to [close] will return this future.
-  Future<void> _closed;
+  Future<void>? _closed;
 
   WebkitDebugger(this._wipDebugger);
 
@@ -29,7 +27,7 @@ class WebkitDebugger implements RemoteDebugger {
 
   @override
   Future<WipResponse> sendCommand(String command,
-          {Map<String, dynamic> params}) =>
+          {Map<String, dynamic>? params}) =>
       _wipDebugger.sendCommand(command, params: params);
 
   @override
@@ -60,14 +58,14 @@ class WebkitDebugger implements RemoteDebugger {
       _wipDebugger.removeBreakpoint(breakpointId);
 
   @override
-  Future<WipResponse> stepInto({Map<String, dynamic> params}) =>
+  Future<WipResponse> stepInto({Map<String, dynamic>? params}) =>
       _wipDebugger.stepInto(params: params);
 
   @override
   Future<WipResponse> stepOut() => _wipDebugger.stepOut();
 
   @override
-  Future<WipResponse> stepOver({Map<String, dynamic> params}) =>
+  Future<WipResponse> stepOver({Map<String, dynamic>? params}) =>
       _wipDebugger.stepOver(params: params);
 
   @override
@@ -78,7 +76,7 @@ class WebkitDebugger implements RemoteDebugger {
 
   @override
   Future<RemoteObject> evaluate(String expression,
-      {bool returnByValue, int contextId}) {
+      {bool? returnByValue, int? contextId}) {
     return _wipDebugger.connection.runtime
         .evaluate(expression, returnByValue: returnByValue);
   }

dwds/lib/src/events.dart

@@ -2,19 +2,17 @@
 // 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.
 
-// @dart = 2.9
-
 import 'dart:async';
 
 import 'package:vm_service/vm_service.dart';
 
 class DwdsStats {
   /// The time when the user starts the debugger.
-  DateTime _debuggerStart;
+  late DateTime _debuggerStart;
   DateTime get debuggerStart => _debuggerStart;
 
   /// The time when dwds launches DevTools.
-  DateTime _devToolsStart;
+  late DateTime _devToolsStart;
   DateTime get devToolsStart => _devToolsStart;
 
   /// Records and returns weither the debugger is ready.
@@ -25,7 +23,8 @@ class DwdsStats {
     return wasReady;
   }
 
-  void updateLoadTime({DateTime debuggerStart, DateTime devToolsStart}) {
+  void updateLoadTime(
+      {required DateTime debuggerStart, required DateTime devToolsStart}) {
     _debuggerStart = debuggerStart;
     _devToolsStart = devToolsStart;
   }
@@ -66,14 +65,14 @@ class DwdsEvent {
 
   DwdsEvent.devtoolsLaunch() : this(DwdsEventKind.devtoolsLaunch, {});
 
-  DwdsEvent.evaluate(String expression, Response result)
+  DwdsEvent.evaluate(String expression, Response? result)
       : this(DwdsEventKind.evaluate, {
           'expression': expression,
           'success': result != null && result is InstanceRef,
           if (result != null && result is ErrorRef) 'error': result,
         });
 
-  DwdsEvent.evaluateInFrame(String expression, Response result)
+  DwdsEvent.evaluateInFrame(String expression, Response? result)
       : this(DwdsEventKind.evaluateInFrame, {
           'expression': expression,
           'success': result != null && result is InstanceRef,
@@ -140,13 +139,13 @@ Stream<DwdsEvent> get eventStream => _eventController.stream;
 /// and appends time and exception details to it if
 /// available.
 Future<T> captureElapsedTime<T>(
-    Future<T> Function() function, DwdsEvent Function(T result) event) async {
+    Future<T> Function() function, DwdsEvent Function(T? result) event) async {
   final stopwatch = Stopwatch()..start();
-  T result;
+  T? result;
   try {
     return result = await function();
   } catch (e) {
-    emitEvent(event(result)
+    emitEvent(event(null)
       ..addException(e)
       ..addElapsedTime(stopwatch.elapsedMilliseconds));
     rethrow;

dwds/lib/src/handlers/socket_connections.dart

@@ -2,8 +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.
 
-// @dart = 2.9
-
 import 'dart:async';
 
 import 'package:async/async.dart';
@@ -56,7 +54,7 @@ class SseSocketHandler extends SocketHandler {
   final SseHandler _sseHandler;
   final StreamController<SseSocketConnection> _connectionsStream =
       StreamController<SseSocketConnection>();
-  StreamQueue<SseSocketConnection> _connectionsStreamQueue;
+  StreamQueue<SseSocketConnection>? _connectionsStreamQueue;
 
   SseSocketHandler(this._sseHandler) {
     unawaited(() async {
@@ -90,8 +88,7 @@ class WebSocketConnection extends SocketConnection {
   StreamSink<dynamic> get sink => _channel.sink;
 
   @override
-  Stream<String> get stream =>
-      _channel.stream.map((dynamic o) => o?.toString());
+  Stream<String> get stream => _channel.stream.map((dynamic o) => o.toString());
 
   @override
   void shutdown() => _channel.sink.close();
@@ -100,10 +97,10 @@ class WebSocketConnection extends SocketConnection {
 /// An implemenation of [SocketHandler] that accepts WebSocket connections and
 /// wraps them in a [WebSocketConnection].
 class WebSocketSocketHandler extends SocketHandler {
-  Handler _handler;
+  late Handler _handler;
   final StreamController<WebSocketConnection> _connectionsStream =
       StreamController<WebSocketConnection>();
-  StreamQueue<WebSocketConnection> _connectionsStreamQueue;
+  StreamQueue<WebSocketConnection>? _connectionsStreamQueue;
 
   WebSocketSocketHandler() {
     _handler = webSocketHandler((WebSocketChannel channel) =>