[flutter_tools] Include mode in app.start event, and forward app.start to DAP clients (#121239)

[flutter_tools] Include mode in app.start event, and forward app.start to DAP clients

packages/flutter_tools/doc/daemon.md

@@ -136,7 +136,7 @@ The `stop()` command takes one parameter, `appId`. It returns a `bool` to indica
 
 #### app.start
 
-This is sent when an app is starting. The `params` field will be a map with the fields `appId`, `directory`, `deviceId`, and `launchMode`.
+This is sent when an app is starting. The `params` field will be a map with the fields `appId`, `directory`, `deviceId`, `launchMode` (`run`/`attach`) and `mode` (`debug`, `profile`, `release`, `jit_release`).
 
 #### app.debugPort
 

packages/flutter_tools/lib/src/commands/daemon.dart

@@ -613,6 +613,7 @@ class AppDomain extends Domain {
       'directory': projectDirectory,
       'supportsRestart': isRestartSupported(enableHotReload, device),
       'launchMode': launchMode.toString(),
+      'mode': runner.debuggingOptions.buildInfo.modeName,
     });
 
     Completer<DebugConnectionInfo>? connectionInfoCompleter;

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

@@ -393,6 +393,16 @@ class FlutterDebugAdapter extends FlutterBaseDebugAdapter {
     // session (which is much slower, but required for profile/release mode).
     final bool supportsRestart = (params['supportsRestart'] as bool?) ?? false;
     sendEvent(CapabilitiesEventBody(capabilities: Capabilities(supportsRestartRequest: supportsRestart)));
+
+    // Send a custom event so the editor has info about the app starting.
+    //
+    // This message contains things like the `deviceId` and `mode` that the
+    // client might not know about if they were inferred or set by users custom
+    // args.
+    sendEvent(
+      RawEventBody(params),
+      eventType: 'flutter.appStart',
+    );
   }
 
   /// Handles the app.started event from Flutter.

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

@@ -107,16 +107,18 @@ class MockFlutterDebugAdapter extends FlutterDebugAdapter {
     // Simulate the app starting by triggering handling of events that Flutter
     // would usually write to stdout.
     if (simulateAppStarted) {
-      simulateStdoutMessage(<String, Object?>{
-        'event': 'app.started',
-      });
       simulateStdoutMessage(<String, Object?>{
         'event': 'app.start',
         'params': <String, Object?>{
           'appId': 'TEST',
           'supportsRestart': supportsRestart,
+          'deviceId': 'flutter-tester',
+          'mode': 'debug',
         }
       });
+      simulateStdoutMessage(<String, Object?>{
+        'event': 'app.started',
+      });
     }
   }
 

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

@@ -452,6 +452,30 @@ void main() {
       await dap.client.terminate();
     });
 
+    testWithoutContext('provides appStarted events to the client', () async {
+      final BasicProject project = BasicProject();
+      await project.setUpIn(tempDir);
+
+      // Launch the app and wait for it to send a 'flutter.appStart' event.
+      final Future<Event> appStartFuture = dap.client.event('flutter.appStart');
+      await Future.wait(<Future<void>>[
+        appStartFuture,
+        dap.client.start(
+          launch: () => dap.client.launch(
+            cwd: project.dir.path,
+            toolArgs: <String>['-d', 'flutter-tester'],
+          ),
+        ),
+      ], eagerError: true);
+
+      await dap.client.terminate();
+
+      final Event appStart = await appStartFuture;
+      final Map<String, Object?> params = appStart.body! as Map<String, Object?>;
+      expect(params['deviceId'], 'flutter-tester');
+      expect(params['mode'], 'debug');
+    });
+
     testWithoutContext('provides appStarted events to the client', () async {
       final BasicProject project = BasicProject();
       await project.setUpIn(tempDir);

packages/flutter_tools/test/integration.shard/flutter_run_test.dart

@@ -68,4 +68,10 @@ void main() {
       matches: isNotEmpty,
     );
   });
+
+  testWithoutContext('reports deviceId and mode in app.start event', () async {
+    await flutter.run();
+    expect(flutter.currentRunningDeviceId, 'flutter-tester');
+    expect(flutter.currentRunningMode, 'debug');
+  });
 }

packages/flutter_tools/test/integration.shard/test_driver.dart

@@ -496,6 +496,11 @@ class FlutterRunTestDriver extends FlutterTestDriver {
   });
 
   String? _currentRunningAppId;
+  String? _currentRunningDeviceId;
+  String? _currentRunningMode;
+
+  String? get currentRunningDeviceId => _currentRunningDeviceId;
+  String? get currentRunningMode => _currentRunningMode;
 
   Future<void> run({
     bool withDebugger = false,
@@ -611,6 +616,7 @@ class FlutterRunTestDriver extends FlutterTestDriver {
 
         // Set this up now, but we don't wait it yet. We want to make sure we don't
         // miss it while waiting for debugPort below.
+        final Future<Map<String, Object?>> start = _waitFor(event: 'app.start', timeout: appStartTimeout);
         final Future<Map<String, Object?>> started = _waitFor(event: 'app.started', timeout: appStartTimeout);
 
         if (withDebugger) {
@@ -630,9 +636,13 @@ class FlutterRunTestDriver extends FlutterTestDriver {
           _attachPort = attachPort;
         }
 
-        // Now await the started event; if it had already happened the future will
+        // Now await the start/started events; if it had already happened the future will
         // have already completed.
-        _currentRunningAppId = ((await started)['params'] as Map<String, Object?>?)?['appId'] as String?;
+        final Map<String, Object?>? startParams = (await start)['params'] as Map<String, Object?>?;
+        final Map<String, Object?>? startedParams = (await started)['params'] as Map<String, Object?>?;
+        _currentRunningAppId = startedParams?['appId'] as String?;
+        _currentRunningDeviceId = startParams?['deviceId'] as String?;
+        _currentRunningMode = startParams?['mode'] as String?;
         prematureExitGuard.complete();
       } on Exception catch (error, stackTrace) {
         prematureExitGuard.completeError(Exception(error.toString()), stackTrace);