Allow attaching to profile builds (#26720)

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

@@ -16,6 +16,7 @@ import '../fuchsia/fuchsia_device.dart';
 import '../globals.dart';
 import '../protocol_discovery.dart';
 import '../resident_runner.dart';
+import '../run_cold.dart';
 import '../run_hot.dart';
 import '../runner/flutter_command.dart';
 
@@ -176,6 +177,7 @@ class AttachCommand extends FlutterCommand {
         : Uri.parse('http://$ipv4Loopback:$localPort/');
     }
     try {
+      final bool useHot = getBuildInfo().isDebug;
       final FlutterDevice flutterDevice = FlutterDevice(
         device,
         trackWidgetCreation: false,
@@ -186,24 +188,32 @@ class AttachCommand extends FlutterCommand {
         targetModel: TargetModel(argResults['target-model']),
       );
       flutterDevice.observatoryUris = <Uri>[ observatoryUri ];
-      final HotRunner hotRunner = hotRunnerFactory.build(
-        <FlutterDevice>[flutterDevice],
+      final List<FlutterDevice> flutterDevices =  <FlutterDevice>[flutterDevice];
+      final DebuggingOptions debuggingOptions = DebuggingOptions.enabled(getBuildInfo());
+      final ResidentRunner runner = useHot ?
+          hotRunnerFactory.build(
+            flutterDevices,
             target: targetFile,
-        debuggingOptions: DebuggingOptions.enabled(getBuildInfo()),
+            debuggingOptions: debuggingOptions,
             packagesFilePath: globalResults['packages'],
             usesTerminalUI: daemon == null,
             projectRootPath: argResults['project-root'],
             dillOutputPath: argResults['output-dill'],
             ipv6: usesIpv6,
+          )
+        : ColdRunner(
+            flutterDevices,
+            target: targetFile,
+            debuggingOptions: debuggingOptions,
+            ipv6: usesIpv6,
           );
       if (attachLogger) {
         flutterDevice.startEchoingDeviceLog();
       }
-
       if (daemon != null) {
         AppInstance app;
         try {
-          app = await daemon.appDomain.launch(hotRunner, hotRunner.attach,
+          app = await daemon.appDomain.launch(runner, runner.attach,
               device, null, true, fs.currentDirectory);
         } catch (error) {
           throwToolExit(error.toString());
@@ -212,7 +222,7 @@ class AttachCommand extends FlutterCommand {
         if (result != 0)
           throwToolExit(null, exitCode: result);
       } else {
-        await hotRunner.attach();
+        await runner.attach();
       }
     } finally {
       final List<ForwardedPort> ports = device.portForwarder.forwardedPorts.toList();

packages/flutter_tools/lib/src/resident_runner.dart

@@ -489,6 +489,11 @@ abstract class ResidentRunner {
     bool shouldBuild = true
   });
 
+  Future<int> attach({
+    Completer<DebugConnectionInfo> connectionInfoCompleter,
+    Completer<void> appStartedCompleter,
+  });
+
   bool get supportsRestart => false;
 
   Future<OperationResult> restart({ bool fullRestart = false, bool pauseAfterRestart = false, String reason }) {

packages/flutter_tools/lib/src/run_cold.dart

@@ -11,6 +11,7 @@ import 'device.dart';
 import 'globals.dart';
 import 'resident_runner.dart';
 import 'tracing.dart';
+import 'vmservice.dart';
 
 // TODO(mklim): Test this, flutter/flutter#23031.
 class ColdRunner extends ResidentRunner {
@@ -34,6 +35,7 @@ class ColdRunner extends ResidentRunner {
 
   final bool traceStartup;
   final File applicationBinary;
+  bool _didAttach = false;
 
   @override
   Future<int> run({
@@ -111,12 +113,50 @@ class ColdRunner extends ResidentRunner {
     return 0;
   }
 
+  @override
+  Future<int> attach({
+    Completer<DebugConnectionInfo> connectionInfoCompleter,
+    Completer<void> appStartedCompleter,
+  }) async {
+    _didAttach = true;
+    try {
+      await connectToServiceProtocol();
+    } catch (error) {
+      printError('Error connecting to the service protocol: $error');
+      return 2;
+    }
+    for (FlutterDevice device in flutterDevices) {
+      device.initLogReader();
+    }
+    await refreshViews();
+    for (FlutterDevice device in flutterDevices) {
+      for (FlutterView view in device.views) {
+        printTrace('Connected to $view.');
+      }
+    }
+    if (stayResident) {
+      setupTerminal();
+      registerSignalHandlers();
+    }
+    appStartedCompleter?.complete();
+    if (stayResident) {
+      return waitForAppToFinish();
+    }
+    await cleanupAtFinish();
+    return 0;
+  }
+
   @override
   Future<void> handleTerminalCommand(String code) async { }
 
   @override
   Future<void> cleanupAfterSignal() async {
     await stopEchoingDeviceLog();
+    if (_didAttach) {
+      appFinished();
+    } else {
+      await stopApp();
+    }
     await stopApp();
   }
 
@@ -145,15 +185,18 @@ class ColdRunner extends ResidentRunner {
         haveAnything = true;
       }
     }
+    final String quitMessage = _didAttach
+      ? 'To detach, press "d"; to quit, press "q".'
+      : 'To quit, press "q".';
     if (haveDetails && !details) {
       if (saveCompilationTrace) {
         printStatus('Compilation training data will be saved when flutter run quits...');
       }
-      printStatus('For a more detailed help message, press "h". To quit, press "q".');
+      printStatus('For a more detailed help message, press "h". $quitMessage');
     } else if (haveAnything) {
-      printStatus('To repeat this help message, press "h". To quit, press "q".');
+      printStatus('To repeat this help message, press "h". $quitMessage');
     } else {
-      printStatus('To quit, press "q".');
+      printStatus(quitMessage);
     }
   }
 

packages/flutter_tools/lib/src/run_hot.dart

@@ -176,6 +176,7 @@ class HotRunner extends ResidentRunner {
     throw 'Failed to compile $expression';
   }
 
+  @override
   Future<int> attach({
     Completer<DebugConnectionInfo> connectionInfoCompleter,
     Completer<void> appStartedCompleter,

packages/flutter_tools/test/resident_runner_test.dart

@@ -40,6 +40,12 @@ class TestRunner extends ResidentRunner {
     String route,
     bool shouldBuild = true,
   }) async => null;
+
+  @override
+  Future<int> attach({
+    Completer<DebugConnectionInfo> connectionInfoCompleter,
+    Completer<void> appStartedCompleter,
+  }) async => null;
 }
 
 void main() {