fix asyncEval integration test failures

Author: rishika0212

packages/devtools_app/test/shared/eval_integration_test.dart

@@ -115,17 +115,18 @@ void main() {
             serviceManager: serviceConnection.serviceManager,
           );
 
-          final instance = await eval
-              .asyncEval(
-                'await Future.error(StateError("foo"), StackTrace.current)',
-                isAlive: isAlive,
-              )
-              .then<FutureFailedException>(
-                (_) => throw Exception(
-                  'The FutureFailedException was not thrown as expected.',
-                ),
-                onError: (Object? err) => err,
-              );
+          late final FutureFailedException instance;
+          try {
+            await eval.asyncEval(
+              'await Future.error(StateError("foo"), StackTrace.current)',
+              isAlive: isAlive,
+            );
+            throw Exception(
+              'The FutureFailedException was not thrown as expected.',
+            );
+          } on FutureFailedException catch (e) {
+            instance = e;
+          }
 
           expect(
             instance.expression,

packages/devtools_app_shared/lib/src/service/eval_on_dart_library.dart

@@ -345,6 +345,21 @@ class EvalOnDartLibrary extends DisposableController
 
   static int _nextAsyncEvalId = 0;
 
+  Future<InstanceRef> _safeEvalWithRetry(
+    EvalOnDartLibrary eval,
+    String expression, {
+    required Disposable? isAlive,
+    Map<String, String>? scope,
+  }) async {
+    try {
+      return await eval.safeEval(expression, isAlive: isAlive, scope: scope);
+    } catch (_) {
+      // In some environments, bootstrap evals can race isolate readiness.
+      await Future<void>.delayed(const Duration(milliseconds: 50));
+      return await eval.safeEval(expression, isAlive: isAlive, scope: scope);
+    }
+  }
+
   EvalOnDartLibrary? _dartDeveloperEvalCache;
   EvalOnDartLibrary get _dartDeveloperEval {
     return _dartDeveloperEvalCache ??= EvalOnDartLibrary(
@@ -395,11 +410,13 @@ class EvalOnDartLibrary extends DisposableController
     final readerGroup = 'asyncEval-$futureId';
 
     /// Workaround to not being able to import libraries directly from an evaluation
-    final postEventRef = await _dartDeveloperEval.safeEval(
+    final postEventRef = await _safeEvalWithRetry(
+      _dartDeveloperEval,
       'postEvent',
       isAlive: isAlive,
     );
-    final widgetInspectorServiceRef = await _widgetInspectorEval.safeEval(
+    final widgetInspectorServiceRef = await _safeEvalWithRetry(
+      _widgetInspectorEval,
       'WidgetInspectorService.instance',
       isAlive: isAlive,
     );
@@ -438,7 +455,7 @@ class EvalOnDartLibrary extends DisposableController
 
     final resultRef = await evalInstance(
       '() {'
-      '  final result = widgetInspectorService.toObject("$readerId", "$readerGroup") as List;'
+      '  final result = widgetInspectorService.toObject("$readerId", "$readerGroup");'
       '  widgetInspectorService.disposeGroup("$readerGroup");'
       '  return result;'
       '}()',