[flutter_tools] add needsFullRestart flag on hot runner (#104562)

packages/flutter_tools/lib/src/isolated/resident_web_runner.dart

@@ -518,6 +518,7 @@ class ResidentWebRunner extends ResidentRunner {
     Completer<void> appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false, // ignored, we don't yet support devtools for web
+    bool needsFullRestart = true,
   }) async {
     if (_chromiumLauncher != null) {
       final Chromium chrome = await _chromiumLauncher.connectedInstance;

packages/flutter_tools/lib/src/resident_runner.dart

@@ -1178,11 +1178,16 @@ abstract class ResidentRunner extends ResidentHandlers {
     String route,
   });
 
+  /// Connect to a flutter application.
+  ///
+  /// [needsFullRestart] defaults to `true`, and controls if the frontend server should
+  /// compile a full dill. This should be set to `false` if this is called in [ResidentRunner.run], since that method already perfoms an initial compilation.
   Future<int> attach({
     Completer<DebugConnectionInfo> connectionInfoCompleter,
     Completer<void> appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false,
+    bool needsFullRestart = true,
   });
 
   @override

packages/flutter_tools/lib/src/run_cold.dart

@@ -152,6 +152,7 @@ class ColdRunner extends ResidentRunner {
     Completer<void> appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false,
+    bool needsFullRestart = true,
   }) async {
     _didAttach = true;
     try {

packages/flutter_tools/lib/src/run_hot.dart

@@ -228,6 +228,7 @@ class HotRunner extends ResidentRunner {
     Completer<void> appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false,
+    bool needsFullRestart = true,
   }) async {
     _didAttach = true;
     try {
@@ -276,7 +277,7 @@ class HotRunner extends ResidentRunner {
     }
 
     final Stopwatch initialUpdateDevFSsTimer = Stopwatch()..start();
-    final UpdateFSReport devfsResult = await _updateDevFS(fullRestart: true);
+    final UpdateFSReport devfsResult = await _updateDevFS(fullRestart: needsFullRestart);
     _addBenchmarkData(
       'hotReloadInitialDevFSSyncMilliseconds',
       initialUpdateDevFSsTimer.elapsed.inMilliseconds,
@@ -436,6 +437,7 @@ class HotRunner extends ResidentRunner {
       connectionInfoCompleter: connectionInfoCompleter,
       appStartedCompleter: appStartedCompleter,
       enableDevTools: enableDevTools,
+      needsFullRestart: false,
     );
   }
 

packages/flutter_tools/test/commands.shard/hermetic/attach_test.dart

@@ -477,6 +477,7 @@ class FakeHotRunner extends Fake implements HotRunner {
     Completer<void> appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false,
+    bool needsFullRestart = true,
   }) {
     return onAttach(connectionInfoCompleter, appStartedCompleter, allowExistingDdsInstance, enableDevTools);
   }

packages/flutter_tools/test/general.shard/hot_test.dart

@@ -514,7 +514,7 @@ void main() {
       final int exitCode = await HotRunner(devices,
         debuggingOptions: DebuggingOptions.enabled(BuildInfo.debug),
         target: 'main.dart',
-      ).attach();
+      ).attach(needsFullRestart: false);
       expect(exitCode, 2);
     }, overrides: <Type, Generator>{
       HotRunnerConfig: () => TestHotRunnerConfig(),

packages/flutter_tools/test/general.shard/terminal_handler_test.dart

@@ -1467,6 +1467,7 @@ class TestRunner extends Fake implements ResidentRunner {
     Completer<void> appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false,
+    bool needsFullRestart = true,
   }) async => null;
 }