[flutter_tools] [dap] Ensure DAP sends app.stop/app.detach during terminate (#108310)

* [flutter_tools] [dap] Ensure DAP sends app.stop/app.detach during terminate

Fixes an issue where the flutter_tester device may not be cleaned up correctly if we just terminate the Flutter process.

* Update integration test expectations

* Revert accidental commit

packages/flutter_tools/lib/src/debug_adapters/flutter_adapter.dart

@@ -400,6 +400,16 @@ class FlutterDebugAdapter extends DartDebugAdapter<FlutterLaunchRequestArguments
     if (isAttach) {
       await preventBreakingAndResume();
     }
+
+    // Send a request to stop/detach to give Flutter chance to do some cleanup.
+    // It's possible the Flutter process will terminate before we process the
+    // response, so accept either a response or the process exiting.
+    final String method = isAttach ? 'app.detach' : 'app.stop';
+    await Future.any<void>(<Future<void>>[
+      sendFlutterRequest(method, <String, Object?>{'appId': _appId}),
+      _process?.exitCode ?? Future<void>.value(),
+    ]);
+
     terminatePids(ProcessSignal.sigterm);
     await _process?.exitCode;
   }

packages/flutter_tools/test/general.shard/dap/flutter_adapter_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:dds/dap.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/cache.dart';
@@ -96,6 +97,29 @@ void main() {
         // Ensure the VM's pid was not recorded.
         expect(adapter.pidsToTerminate, isNot(contains(123)));
       });
+
+      test('calls "app.stop" on terminateRequest', () async {
+        final MockFlutterDebugAdapter adapter = MockFlutterDebugAdapter(
+          fileSystem: MemoryFileSystem.test(style: fsStyle),
+          platform: platform,
+        );
+
+        final FlutterLaunchRequestArguments args = FlutterLaunchRequestArguments(
+          cwd: '/project',
+          program: 'foo.dart',
+        );
+
+        await adapter.configurationDoneRequest(MockRequest(), null, () {});
+        final Completer<void> launchCompleter = Completer<void>();
+        await adapter.launchRequest(MockRequest(), args, launchCompleter.complete);
+        await launchCompleter.future;
+
+        final Completer<void> terminateCompleter = Completer<void>();
+        await adapter.terminateRequest(MockRequest(), TerminateArguments(restart: false), terminateCompleter.complete);
+        await terminateCompleter.future;
+
+        expect(adapter.flutterRequests, contains('app.stop'));
+      });
     });
 
     group('attachRequest', () {
@@ -139,6 +163,28 @@ void main() {
         // Ensure the VM's pid was not recorded.
         expect(adapter.pidsToTerminate, isNot(contains(123)));
       });
+
+      test('calls "app.detach" on terminateRequest', () async {
+        final MockFlutterDebugAdapter adapter = MockFlutterDebugAdapter(
+          fileSystem: MemoryFileSystem.test(style: fsStyle),
+          platform: platform,
+        );
+
+        final FlutterAttachRequestArguments args = FlutterAttachRequestArguments(
+          cwd: '/project',
+        );
+
+        await adapter.configurationDoneRequest(MockRequest(), null, () {});
+        final Completer<void> attachCompleter = Completer<void>();
+        await adapter.attachRequest(MockRequest(), args, attachCompleter.complete);
+        await attachCompleter.future;
+
+        final Completer<void> terminateCompleter = Completer<void>();
+        await adapter.terminateRequest(MockRequest(), TerminateArguments(restart: false), terminateCompleter.complete);
+        await terminateCompleter.future;
+
+        expect(adapter.flutterRequests, contains('app.detach'));
+      });
     });
 
     group('--start-paused', () {

packages/flutter_tools/test/general.shard/dap/mocks.dart

@@ -43,6 +43,7 @@ class MockFlutterDebugAdapter extends FlutterDebugAdapter {
   late String executable;
   late List<String> processArgs;
   late Map<String, String>? env;
+  final List<String> flutterRequests = <String>[];
 
   @override
   Future<void> launchAsProcess({
@@ -59,6 +60,16 @@ class MockFlutterDebugAdapter extends FlutterDebugAdapter {
     appStartedCompleter.complete();
   }
 
+  @override
+  Future<Object?> sendFlutterRequest(
+    String method,
+    Map<String, Object?>? params, {
+    bool failSilently = true,
+  }) {
+    flutterRequests.add(method);
+    return super.sendFlutterRequest(method, params, failSilently: failSilently);
+  }
+
   @override
   Future<void> get debuggerInitialized {
     // If we were mocking debug mode, then simulate the debugger initializing.

packages/flutter_tools/test/integration.shard/debug_adapter/flutter_adapter_test.dart

@@ -64,6 +64,7 @@ void main() {
         'Launching $relativeMainPath on Flutter test device in debug mode...',
         startsWith('Connecting to VM Service at'),
         'topLevelFunction',
+        'Application finished.',
         '',
         startsWith('Exited'),
       ]);
@@ -94,6 +95,7 @@ void main() {
       expectLines(output, <Object>[
         'Launching $relativeMainPath on Flutter test device in debug mode...',
         'topLevelFunction',
+        'Application finished.',
         '',
         startsWith('Exited'),
       ]);