Support Set instance inspection in debugger page (#5323)

Author: elliette

packages/devtools_app/lib/src/shared/diagnostics/dart_object_node.dart

@@ -243,7 +243,8 @@ class DartObjectNode extends TreeNode<DartObjectNode> {
           (value.kind!.endsWith('List') ||
               value.kind == InstanceKind.kList ||
               value.kind == InstanceKind.kMap ||
-              value.kind == InstanceKind.kRecord)) {
+              value.kind == InstanceKind.kRecord ||
+              isSet)) {
         return value.length ?? 0;
       }
     }
@@ -253,6 +254,20 @@ class DartObjectNode extends TreeNode<DartObjectNode> {
 
   int? _childCount;
 
+  // TODO(elliette): Can remove this workaround once DWDS correctly returns
+  // InstanceKind.kSet for the kind of `Sets`. See:
+  // https://github.com/dart-lang/webdev/issues/2001
+  bool get isSet {
+    final value = this.value;
+    if (value is InstanceRef) {
+      final kind = value.kind ?? '';
+      if (kind == InstanceKind.kSet) return true;
+      final name = value.classRef?.name ?? '';
+      if (name.contains('Set')) return true;
+    }
+    return false;
+  }
+
   bool treeInitializeStarted = false;
   bool treeInitializeComplete = false;
 
@@ -319,6 +334,7 @@ class DartObjectNode extends TreeNode<DartObjectNode> {
       // List, Map, Uint8List, Uint16List, etc...
       if (kind != null && kind == InstanceKind.kList ||
           kind == InstanceKind.kMap ||
+          kind == InstanceKind.kSet ||
           kind!.endsWith('List')) {
         // TODO(elliette): Determine the signature from type parameters, see:
         // https://api.flutter.dev/flutter/vm_service/ClassRef/typeParameters.html

packages/devtools_app/lib/src/shared/diagnostics/tree_builder.dart

@@ -259,6 +259,11 @@ Future<void> _addChildrenToInstanceVariable({
     default:
       break;
   }
+
+  if (variable.isSet) {
+    variable.addAllChildren(createVariablesForSets(value, isolateRef));
+  }
+
   if (value.fields != null && value.kind != InstanceKind.kRecord) {
     variable.addAllChildren(
       createVariablesForFields(

packages/devtools_app/lib/src/shared/diagnostics/variable_factory.dart

@@ -461,6 +461,19 @@ List<DartObjectNode> createVariablesForBytes(
   return variables;
 }
 
+List<DartObjectNode> createVariablesForSets(
+  Instance instance,
+  IsolateRef? isolateRef,
+) {
+  final elements = instance.elements ?? [];
+  return elements.map((element) {
+    return DartObjectNode.fromValue(
+      value: element,
+      isolateRef: isolateRef,
+    );
+  }).toList();
+}
+
 List<DartObjectNode> createVariablesForList(
   Instance instance,
   IsolateRef? isolateRef,

packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md

@@ -29,6 +29,7 @@ in deeply nested trees - [#5181](https://github.com/flutter/devtools/pull/5181)
 * Add support for browser navigation history when navigating using the `File Explorer` [#4906](https://github.com/flutter/devtools/pull/4906).
 * Designate positional fields for `Record` types with the getter syntax beginning at `$1` [#5272](https://github.com/flutter/devtools/pull/5272)
 * Fix variable inspection for `Map` and `List` instances: [#5320](https://github.com/flutter/devtools/pull/5320)
+* Fix variable inspection for `Set` instances: [#5323](https://github.com/flutter/devtools/pull/5323)
 
 ## Network profiler updates
 * Improve reliability and performance of the Network tab - [#5056](https://github.com/flutter/devtools/pull/5056)