fix(shadcn_flutter): sync _children when ContextMenu switches between items and itemsBuilder (#1011)

test/features/workspace/context_menu_mode_switch_test.dart

@@ -0,0 +1,187 @@
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart' as material;
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/theme/querya_theme.dart';
+import 'package:shadcn_flutter/shadcn_flutter.dart';
+
+material.Widget _testShell({required material.Widget child}) {
+  final td = QueryaTheme.darkDefault
+      .toShadcnThemeData()
+      .copyWith(platform: () => material.TargetPlatform.linux);
+  return ShadcnApp(
+    theme: td,
+    home: material.Scaffold(
+      body: child,
+    ),
+  );
+}
+
+Future<void> _secondaryClick(WidgetTester tester, Finder finder) async {
+  final gesture = await tester.startGesture(
+    tester.getCenter(finder),
+    buttons: kSecondaryMouseButton,
+  );
+  await gesture.up();
+  await tester.pump();
+  await tester.pump(const Duration(milliseconds: 350));
+}
+
+class _DynamicContextMenuTestHost extends material.StatefulWidget {
+  const _DynamicContextMenuTestHost({
+    super.key,
+    required this.initialItems,
+    this.initialItemsBuilder,
+  });
+
+  final List<MenuItem>? initialItems;
+  final List<MenuItem> Function(material.BuildContext)? initialItemsBuilder;
+
+  @override
+  State<_DynamicContextMenuTestHost> createState() =>
+      _DynamicContextMenuTestHostState();
+}
+
+class _DynamicContextMenuTestHostState
+    extends material.State<_DynamicContextMenuTestHost> {
+  late List<MenuItem>? items = widget.initialItems;
+  late List<MenuItem> Function(material.BuildContext)? itemsBuilder =
+      widget.initialItemsBuilder;
+
+  void update({
+    List<MenuItem>? newItems,
+    List<MenuItem> Function(material.BuildContext)? newItemsBuilder,
+  }) {
+    setState(() {
+      items = newItems;
+      itemsBuilder = newItemsBuilder;
+    });
+  }
+
+  @override
+  material.Widget build(material.BuildContext context) {
+    return material.Center(
+      child: ContextMenu(
+        items: items,
+        itemsBuilder: itemsBuilder,
+        child: const material.Text('Target Box'),
+      ),
+    );
+  }
+}
+
+void main() {
+  group('ContextMenu mode switching (#1011)', () {
+    testWidgets(
+        'switches from itemsBuilder to items at runtime without throwing',
+        (tester) async {
+      final hostKey =
+          material.GlobalKey<_DynamicContextMenuTestHostState>();
+
+      await tester.pumpWidget(
+        _testShell(
+          child: _DynamicContextMenuTestHost(
+            key: hostKey,
+            initialItems: null,
+            initialItemsBuilder: (context) => [
+              const MenuButton(child: Text('Lazy Item 1')),
+            ],
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // Switch to eager items without itemsBuilder
+      hostKey.currentState!.update(
+        newItems: [
+          const MenuButton(child: Text('Eager Item 1')),
+        ],
+        newItemsBuilder: null,
+      );
+      await tester.pumpAndSettle();
+
+      // Right-clicking the target box must resolve eager items and open the menu
+      // without throwing "Null check operator used on a null value".
+      await _secondaryClick(tester, find.text('Target Box'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Eager Item 1'), findsOneWidget);
+      expect(find.text('Lazy Item 1'), findsNothing);
+    });
+
+    testWidgets(
+        'switches from items to itemsBuilder at runtime and invokes builder',
+        (tester) async {
+      final hostKey =
+          material.GlobalKey<_DynamicContextMenuTestHostState>();
+
+      await tester.pumpWidget(
+        _testShell(
+          child: _DynamicContextMenuTestHost(
+            key: hostKey,
+            initialItems: const [
+              MenuButton(child: Text('Old Eager Item')),
+            ],
+            initialItemsBuilder: null,
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      var builderCallCount = 0;
+
+      // Switch to lazy itemsBuilder mode
+      hostKey.currentState!.update(
+        newItems: null,
+        newItemsBuilder: (context) {
+          builderCallCount++;
+          return [
+            const MenuButton(child: Text('New Lazy Item')),
+          ];
+        },
+      );
+      await tester.pumpAndSettle();
+
+      expect(builderCallCount, 0);
+
+      // Open context menu — should call itemsBuilder, not stale eager children
+      await _secondaryClick(tester, find.text('Target Box'));
+      await tester.pumpAndSettle();
+
+      expect(builderCallCount, 1);
+      expect(find.text('New Lazy Item'), findsOneWidget);
+      expect(find.text('Old Eager Item'), findsNothing);
+    });
+
+    testWidgets('updates items when remaining in eager mode', (tester) async {
+      final hostKey =
+          material.GlobalKey<_DynamicContextMenuTestHostState>();
+
+      await tester.pumpWidget(
+        _testShell(
+          child: _DynamicContextMenuTestHost(
+            key: hostKey,
+            initialItems: const [
+              MenuButton(child: Text('Version 1 Item')),
+            ],
+            initialItemsBuilder: null,
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      hostKey.currentState!.update(
+        newItems: const [
+          MenuButton(child: Text('Version 2 Item')),
+        ],
+        newItemsBuilder: null,
+      );
+      await tester.pumpAndSettle();
+
+      await _secondaryClick(tester, find.text('Target Box'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Version 2 Item'), findsOneWidget);
+      expect(find.text('Version 1 Item'), findsNothing);
+    });
+  });
+}

third_party/shadcn_flutter/lib/src/components/menu/context_menu.dart

@@ -591,12 +591,18 @@ class _ContextMenuState extends State<ContextMenu> {
     super.didUpdateWidget(oldWidget);
     final items = widget.items;
     final oldItems = oldWidget.items;
-    if (items != null &&
-        oldItems != null &&
-        !listEquals(items, oldItems)) {
-      WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
-        if (mounted) _children?.value = items;
-      });
+    if (items != null) {
+      if (oldItems == null || _children == null) {
+        _children?.dispose();
+        _children = ValueNotifier(items);
+      } else if (!listEquals(items, oldItems)) {
+        WidgetsBinding.instance.addPostFrameCallback((timeStamp) {
+          if (mounted) _children?.value = items;
+        });
+      }
+    } else if (oldItems != null || _children != null) {
+      _children?.dispose();
+      _children = null;
     }
   }