[dds/dap] Handle some additional error causes when resuming isolates

Fixes https://github.com/flutter/flutter/issues/125064.

Change-Id: I521fe29d0f269694dc6c2b993d1e400c495b0605
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/296560
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>

pkg/dds/CHANGELOG.md

@@ -1,3 +1,6 @@
+# 2.7.9
+- [DAP] Configuring and resuming isolates will no longer cause a crash if the isolate exits before the request is processed.
+
 # 2.7.8
 - [DAP] Sentinel values (such as uninitialized fields/locals) will no longer cause `scopesRequest`/`variablesRequest` to fail, instead showing appropriate text (like "<not initialized>") against the variable.
 

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

@@ -279,6 +279,17 @@ class IsolateManager {
     thread.hasPendingResume = true;
     try {
       await _adapter.vmService?.resume(thread.isolate.id!, step: resumeType);
+    } on vm.SentinelException {
+      // It's possible during these async requests that the isolate went away
+      // (for example a shutdown/restart) and we no longer care about
+      // resuming it.
+    } on vm.RPCError catch (e) {
+      if (e.code == RpcErrorCodes.kIsolateMustBePaused) {
+        // It's possible something else resumed the thread (such as if another
+        // debugger is attached), we can just continue.
+      } else {
+        rethrow;
+      }
     } finally {
       thread.hasPendingResume = false;
     }
@@ -612,13 +623,19 @@ class IsolateManager {
   ) async {
     final isolateId = isolate.id!;
     final uriStrings = uris.map((uri) => uri.toString()).toList();
-    final res = await _adapter.vmService
-        ?.lookupResolvedPackageUris(isolateId, uriStrings, local: true);
+    try {
+      final res = await _adapter.vmService
+          ?.lookupResolvedPackageUris(isolateId, uriStrings, local: true);
 
-    return res?.uris
-        ?.cast<String?>()
-        .map((uri) => uri != null ? Uri.parse(uri) : null)
-        .toList();
+      return res?.uris
+          ?.cast<String?>()
+          .map((uri) => uri != null ? Uri.parse(uri) : null)
+          .toList();
+    } on vm.SentinelException {
+      // If the isolate disappeared before we sent this request, just return
+      // null responses.
+      return uris.map((e) => null).toList();
+    }
   }
 
   /// Interpolates and prints messages for any log points.

pkg/dds/lib/src/rpc_error_codes.dart

@@ -31,7 +31,7 @@ abstract class RpcErrorCodes {
   static const kStreamNotSubscribed = 104;
 
   // static const kIsolateMustBeRunnable = 105;
-  // static const kIsolateMustBePaused = 106;
+  static const kIsolateMustBePaused = 106;
   // static const kCannotResume = 107;
   // static const kIsolateIsReloading = 108;
   // static const kIsolateReloadBarred = 109;

pkg/dds/pubspec.yaml

@@ -1,5 +1,5 @@
 name: dds
-version: 2.7.8
+version: 2.7.9
 description: >-
   A library used to spawn the Dart Developer Service, used to communicate with
   a Dart VM Service instance.

pkg/dds/test/dap/integration/debug_breakpoints_test.dart

@@ -533,6 +533,41 @@ void main(List<String> args) async {
         client.stepIn(stop.threadId!),
       ], eagerError: true);
     });
+
+    test('does not fail if two debug clients resume the same thread', () async {
+      final testFile = dap.createTestFile(infiniteRunningProgram);
+      final breakpointLine = lineWith(testFile, breakpointMarker);
+
+      // Start a program and hit a breakpoint.
+      final client1 = dap.client;
+      final stop1 = await client1.hitBreakpoint(testFile, breakpointLine);
+      final vmServiceUri = (await client1.vmServiceUri)!;
+      final thread1 = stop1.threadId!;
+
+      // Attach a second debug adapter to it.
+      final dap2 = await DapTestSession.setUp();
+      final client2 = dap2.client;
+      await Future.wait([
+        // We'll still get event for existing pause.
+        client2.expectStop('breakpoint'),
+        client2.start(
+          launch: () => client2.attach(
+            vmServiceUri: vmServiceUri.toString(),
+            autoResume: false,
+            cwd: dap.testAppDir.path,
+          ),
+        ),
+      ]);
+      final thread2 = (await client2.getValidThreads()).threads.single.id;
+
+      // Send resumes to both and ensure they complete without errors.
+      await Future.wait([
+        client1.continue_(thread1),
+        client2.continue_(thread2),
+      ], eagerError: true);
+
+      await dap2.tearDown();
+    });
   }, timeout: Timeout.none);
 
   group('debug mode conditional breakpoints', () {

pkg/dds/test/dap/integration/test_scripts.dart

@@ -91,6 +91,19 @@ String stringPrintingProgram(String text) {
 ''';
 }
 
+/// A simple Dart script that just loops forever sleeping for 1 second each
+/// iteration.
+///
+/// A breakpoint marker is included before the loop.
+const infiniteRunningProgram = '''
+  void main(List<String> args) async {
+    print('Looping'); $breakpointMarker
+    while (true) {
+      await Future.delayed(const Duration(seconds: 1));
+    }
+  }
+''';
+
 /// A simple async Dart script that when stopped at the line of '// BREAKPOINT'
 /// will contain multiple stack frames across some async boundaries.
 const simpleAsyncProgram = '''