Handle edge cases for eval and pass needed parameters to HeapObjectGraph.

packages/devtools_app/lib/src/screens/memory/panes/diff/controller/sampler.dart

@@ -11,42 +11,51 @@ import '../../../shared/primitives/class_name.dart';
 import '../../../shared/primitives/instance_set_view.dart';
 
 class HeapClassSampler extends ClassSampler {
-  HeapClassSampler(this.className, this.objects);
+  HeapClassSampler(this.objects, this.heap);
 
-  final HeapClassName className;
   final SingleClassStats objects;
+  final AdaptedHeapData heap;
 
   IsolateRef get _mainIsolateRef =>
       serviceManager.isolateManager.mainIsolate.value!;
 
-  Future<InstanceRef> _oneInstance() async {
+  Future<InstanceRef?> _oneInstance() async {
     final isolateId = _mainIsolateRef.id!;
 
     // TODO(polina-c): It would be great to find out how to avoid full scan of classes.
     final theClass = (await serviceManager.service!.getClassList(isolateId))
         .classes!
-        .firstWhere((ref) => className.matches(ref));
+        .firstWhere((ref) => objects.heapClass.matches(ref));
 
     final instances = await serviceManager.service!.getInstances(
       isolateId,
       theClass.id!,
       1,
     );
 
-    return instances.instances!.first as InstanceRef;
+    final result = instances.instances!.first;
+
+    if (result is InstanceRef) return result;
+
+    return null;
   }
 
   @override
   Future<void> oneVariableToConsole() async {
     final instance = await _oneInstance();
 
-    // drop to console
-    serviceManager.consoleService.appendInstanceRef(
-      value: instance,
-      diagnostic: null,
-      isolateRef: _mainIsolateRef,
-      forceScrollIntoView: true,
-    );
+    if (instance == null) {
+      serviceManager.consoleService
+          .appendStdio('the instance cannot be evaluated');
+    } else {
+      // drop to console
+      serviceManager.consoleService.appendInstanceRef(
+        value: instance,
+        diagnostic: null,
+        isolateRef: _mainIsolateRef,
+        forceScrollIntoView: true,
+      );
+    }
 
     // TODO (polina-c): remove the commented code
     // before opening the flag.
@@ -67,6 +76,17 @@ class HeapClassSampler extends ClassSampler {
 
   @override
   Future<void> instanceGraphToConsole() async {
-    serviceManager.consoleService.appendInstanceGraph(HeapObjectGraph('hello'));
+    serviceManager.consoleService.appendInstanceGraph(
+      HeapObjectGraph(
+        heap,
+        objects.objects.objectsByCodes.keys.first,
+        objects.heapClass,
+      ),
+    );
   }
+
+  @override
+  bool get isEvalEnabled =>
+      objects.heapClass.classType(serviceManager.rootInfoNow().package) !=
+      ClassType.runtime;
 }

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/classes_table_single.dart

@@ -14,6 +14,7 @@ import '../../../../../shared/table/table_data.dart';
 import '../../../../../shared/theme.dart';
 import '../../../../../shared/utils.dart';
 import '../../../shared/heap/heap.dart';
+import '../../../shared/heap/model.dart';
 import '../../../shared/primitives/instance_set_view.dart';
 import '../../../shared/primitives/simple_elements.dart';
 import '../../../shared/shared_memory_widgets.dart';
@@ -79,14 +80,16 @@ class _ClassNameColumn extends ColumnData<SingleClassStats>
 
 class _InstanceColumn extends ColumnData<SingleClassStats>
     implements ColumnRenderer<SingleClassStats> {
-  _InstanceColumn()
+  _InstanceColumn(this.heap)
       : super(
           'Instances',
           titleTooltip: nonGcableInstancesColumnTooltip,
           fixedWidthPx: scaleByFontFactor(180.0),
           alignment: ColumnAlignment.right,
         );
 
+  final AdaptedHeapData heap;
+
   @override
   int getValue(SingleClassStats classStats) => classStats.objects.instanceCount;
 
@@ -103,6 +106,7 @@ class _InstanceColumn extends ColumnData<SingleClassStats>
     if (!FeatureFlags.evalAndBrowse) return null;
 
     final theme = Theme.of(context);
+    final showMenu = isRowSelected;
 
     return Row(
       mainAxisAlignment: MainAxisAlignment.end,
@@ -112,9 +116,8 @@ class _InstanceColumn extends ColumnData<SingleClassStats>
               isRowSelected ? theme.selectedTextStyle : theme.regularTextStyle,
           count: getValue(data),
           gaContext: gac.MemoryAreas.snapshotSingle,
-          sampleObtainer:
-              isRowSelected ? HeapClassSampler(data.heapClass, data) : null,
-          showMenu: isRowSelected,
+          sampleObtainer: showMenu ? HeapClassSampler(data, heap) : null,
+          showMenu: showMenu,
         ),
       ],
     );
@@ -178,7 +181,7 @@ class _RetainedSizeColumn extends ColumnData<SingleClassStats> {
 }
 
 class _ClassesTableSingleColumns {
-  _ClassesTableSingleColumns(this.totalSize, this.classFilterButton);
+  _ClassesTableSingleColumns(this.totalSize, this.classFilterButton, this.heap);
 
   /// Is needed to calculate percentage.
   final int totalSize;
@@ -187,9 +190,11 @@ class _ClassesTableSingleColumns {
 
   late final retainedSizeColumn = _RetainedSizeColumn(totalSize);
 
+  final AdaptedHeapData heap;
+
   late final columnList = <ColumnData<SingleClassStats>>[
     _ClassNameColumn(classFilterButton),
-    _InstanceColumn(),
+    _InstanceColumn(heap),
     _ShallowSizeColumn(),
     retainedSizeColumn,
   ];
@@ -202,21 +207,29 @@ class ClassesTableSingle extends StatelessWidget {
     required this.selection,
     required this.totalSize,
     required this.classFilterButton,
+    required this.heap,
   });
 
   final int totalSize;
 
   final Widget classFilterButton;
 
   final List<SingleClassStats> classes;
+
   final ValueNotifier<SingleClassStats?> selection;
 
+  final AdaptedHeapData heap;
+
   @override
   Widget build(BuildContext context) {
     // We want to preserve the sorting and sort directions for ClassesTableDiff
     // no matter what the data passed to it is.
     const dataKey = 'ClassesTableSingle';
-    final columns = _ClassesTableSingleColumns(totalSize, classFilterButton);
+    final columns = _ClassesTableSingleColumns(
+      totalSize,
+      classFilterButton,
+      heap,
+    );
     return FlatTable<SingleClassStats>(
       columns: columns.columnList,
       data: classes,

packages/devtools_app/lib/src/screens/memory/panes/diff/widgets/snapshot_view.dart

@@ -59,6 +59,10 @@ class SnapshotView extends StatelessWidget {
             selection: controller.derived.selectedSingleClassStats,
             totalSize: totalSize!,
             classFilterButton: classFilterButton,
+            heap:
+                (controller.derived.selectedItem.value as SnapshotInstanceItem)
+                    .heap!
+                    .data,
           );
         } else if (diffClasses != null) {
           classTable = ClassesTableDiff(

packages/devtools_app/lib/src/screens/memory/shared/heap/model.dart

@@ -327,7 +327,9 @@ mixin Sealable {
 class HeapObjectGraph {
   //TODO(polina-c): add needed fields
 
-  HeapObjectGraph(this.name);
+  HeapObjectGraph(this.heap, this.identityHashCode, this.className);
 
-  final String name;
+  final int identityHashCode;
+  final HeapClassName className;
+  final AdaptedHeapData heap;
 }

packages/devtools_app/lib/src/screens/memory/shared/primitives/instance_set_view.dart

@@ -13,6 +13,7 @@ import '../../../../shared/primitives/utils.dart';
 abstract class ClassSampler {
   Future<void> oneVariableToConsole();
   void instanceGraphToConsole();
+  bool get isEvalEnabled;
 }
 
 /// A button with label '...' to show near count of instances,
@@ -53,17 +54,23 @@ class InstanceSetButton extends StatelessWidget {
 }
 
 class _StoreAsVariableMenu extends StatelessWidget {
-  const _StoreAsVariableMenu(this.menuText, this.sampleObtainer);
+  const _StoreAsVariableMenu(this.sampleObtainer);
 
-  final String menuText;
   final ClassSampler sampleObtainer;
 
   @override
   Widget build(BuildContext context) {
+    final enabled = sampleObtainer.isEvalEnabled;
+    const menuText = 'Store as a console variable';
+
+    if (!enabled) {
+      return const MenuItemButton(child: Text(menuText));
+    }
+
     return SubmenuButton(
       menuChildren: <Widget>[
         MenuItemButton(
-          onPressed: sampleObtainer.oneVariableToConsole,
+          onPressed: enabled ? sampleObtainer.oneVariableToConsole : null,
           child: const Text('One instance'),
         ),
         const MenuItemButton(
@@ -73,16 +80,13 @@ class _StoreAsVariableMenu extends StatelessWidget {
           child: Text('All instances'),
         ),
       ],
-      child: Text(menuText),
+      child: const Text(menuText),
     );
   }
 }
 
 List<Widget> _menu(ClassSampler sampleObtainer) => [
-      _StoreAsVariableMenu(
-        'Store as a console variable',
-        sampleObtainer,
-      ),
+      _StoreAsVariableMenu(sampleObtainer),
       MenuItemButton(
         onPressed: sampleObtainer.instanceGraphToConsole,
         child: const Text('Browse references for a single instance in console'),

packages/devtools_app/lib/src/shared/console/console.dart

@@ -245,7 +245,7 @@ class _ConsoleOutputState extends State<_ConsoleOutput>
               variable: line.variable,
             );
           } else if (line is GraphConsoleLine) {
-            return Text(line.graph.name);
+            return Text(line.graph.toString());
           } else {
             assert(
               false,

packages/devtools_app/lib/src/shared/console/console_service.dart

@@ -82,11 +82,6 @@ class GraphConsoleLine extends ConsoleLine {
   GraphConsoleLine(this.graph, {bool forceScrollIntoView = false})
       : super._(forceScrollIntoView);
   final HeapObjectGraph graph;
-
-  @override
-  String toString() {
-    return graph.name;
-  }
 }
 
 /// Source of truth for the state of the Console including both events from the