[dds/dap] Include Isolate IDs in Threads when used over DDS

See #53086

Change-Id: I380744f9e0d604168f026684b31fe689bb8947c8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/317701
Reviewed-by: Ben Konyi <[email protected]>

pkg/dds/CHANGELOG.md

@@ -1,5 +1,6 @@
 # 2.9.5
 - [DAP] The change to use VM Service Isolate numbers for `threadId`s has been reverted because Isolate numbers can be larger than the 32-bit integers allowed in DAP.
+- [DAP] Threads returned from `threadsRequest` from the DDS DAP handler now include `isolateId` fields to allow mapping back to VM Service Isolates.
 
 # 2.9.4
 - Updated `devtools_shared` to ^2.26.1

pkg/dds/lib/src/dap/adapters/dds_hosted_adapter.dart

@@ -100,6 +100,28 @@ class DdsHostedAdapter extends DartDebugAdapter<DartLaunchRequestArguments,
     unawaited(connectDebugger(ddsUri!));
   }
 
+  /// Handles a request from the client for the list of threads.
+  ///
+  /// Unlike the base implementation, the DDS version includes additional fields
+  /// in the response for `isolateId`.
+  @override
+  Future<void> threadsRequest(
+    Request request,
+    void args,
+    void Function(ThreadsResponseBody) sendResponse,
+  ) async {
+    final threads = [
+      for (final thread in isolateManager.threads)
+        ThreadWithIsolateId(
+          id: thread.threadId,
+          name: thread.isolate.name ?? '<unnamed isolate>',
+          isolateId:
+              thread.isolate.id ?? '<unknown isolate ${thread.threadId}>',
+        )
+    ];
+    sendResponse(ThreadsResponseBody(threads: threads));
+  }
+
   /// Handles custom requests that are specific to the DDS-hosted adapter, such
   /// as translating between VM IDs and DAP IDs.
   @override
@@ -228,3 +250,22 @@ class DdsHostedAdapter extends DartDebugAdapter<DartLaunchRequestArguments,
     _dapEventsController.stream.listen(eventHandler);
   }
 }
+
+/// Extends [Thread] with [isolateId] for easier mapping for clients using both
+/// DAP and VM Service.
+class ThreadWithIsolateId extends Thread {
+  /// The ID of the Isolate this thread represents.
+  final String isolateId;
+
+  ThreadWithIsolateId({
+    required super.id,
+    required super.name,
+    required this.isolateId,
+  });
+
+  @override
+  Map<String, Object?> toJson() => {
+        ...super.toJson(),
+        'isolateId': isolateId,
+      };
+}

pkg/dds/lib/src/dap/constants.dart

@@ -6,6 +6,7 @@ class Command {
   static const initialize = 'initialize';
   static const configurationDone = 'configurationDone';
   static const attach = 'attach';
+  static const threads = 'threads';
   static const createVariableForInstance = r'$/createVariableForInstance';
   static const getVariablesInstanceId = r'$/getVariablesInstanceId';
 }

pkg/dds/test/dap_handler_test.dart

@@ -35,7 +35,8 @@ void main() {
   });
 
   var nextSeq = 1;
-  Future<DapResponse> sendDapRequest(String request, Object? arguments) async {
+  Future<DapResponse> sendDapRequest(String request,
+      [Object? arguments]) async {
     final result = await service.sendDapRequest(
       jsonEncode(
         Request(
@@ -153,4 +154,28 @@ void main() {
     expect(await variableToString(variablesReference), 'MyClass');
     expect(await instanceToString(isolateId, mappedInstanceId), 'MyClass');
   });
+
+  test('DAP includes Isolate IDs in Threads', () async {
+    await createProcess(pauseOnStart: false);
+    dds = await DartDevelopmentService.startDartDevelopmentService(
+      remoteVmServiceUri,
+    );
+    service = await vmServiceConnectUri(dds!.wsUri!.toString());
+
+    // Get the expected isolateId.
+    final isolateId = (await service.getVM()).isolates!.first.id!;
+
+    // Ask DAP for all threads.
+    final threadsResult = await sendDapRequest(Command.threads);
+    final threadsBody = threadsResult.dapResponse.body as Map<String, Object?>;
+
+    final threads = threadsBody['threads'] as List;
+    expect(threads, hasLength(1));
+    final thread = threads[0] as Map<String, Object?>;
+    expect(thread, {
+      'id': 1,
+      'name': 'main',
+      'isolateId': isolateId,
+    });
+  });
 }