[two_dimensional_scrollables] Fix TreeView bug when animation duration is zero (#7475)

Fixes [#153889 ](flutter/flutter#154292) an issue where nodes were being removed incorrectly when using `AnimationStyle.noAnimation `or the animation duration was zero seconds, which previously caused the erratic behavior due to hidden state updates. Similar to flutter/flutter#153890.

Author: Mairramer

packages/two_dimensional_scrollables/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.2
+
+* Fixes a bug where the TreeView would not update correctly when the animation duration is zero.
+
 ## 0.3.1
 
 * Adds generics to the callbacks and builders of TreeView.

packages/two_dimensional_scrollables/lib/src/tree_view/tree.dart

@@ -886,6 +886,15 @@ class _TreeViewState<T> extends State<TreeView<T>>
       if (widget.onNodeToggle != null) {
         widget.onNodeToggle!(node);
       }
+
+      // If animation is disabled or duration is zero, skip the animation
+      // and update the active nodes immediately. This ensures the tree
+      // is updated correctly when the node's children are no longer active.
+      if (widget.toggleAnimationStyle?.duration == Duration.zero) {
+        _unpackActiveNodes();
+        return;
+      }
+
       final AnimationController controller =
           _currentAnimationForParent[node]?.controller ??
               AnimationController(

packages/two_dimensional_scrollables/pubspec.yaml

@@ -1,6 +1,6 @@
 name: two_dimensional_scrollables
 description: Widgets that scroll using the two dimensional scrolling foundation.
-version: 0.3.1
+version: 0.3.2
 repository: https://github.com/flutter/packages/tree/main/packages/two_dimensional_scrollables
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+two_dimensional_scrollables%22+
 

packages/two_dimensional_scrollables/test/tree_view/tree_test.dart

@@ -718,6 +718,102 @@ void main() {
       expect(treeView.treeNodeBuilder, isA<TreeViewNodeBuilder<String>>());
       expect(treeView.treeRowBuilder, isA<TreeViewRowBuilder<String>>());
     });
+
+    testWidgets(
+        'TreeViewNode should expand/collapse correctly when the animation duration is set to zero.',
+        (WidgetTester tester) async {
+      // Regression test for https://github.com/flutter/flutter/issues/154292
+      final TreeViewController controller = TreeViewController();
+      final List<TreeViewNode<String>> tree = <TreeViewNode<String>>[
+        TreeViewNode<String>('First'),
+        TreeViewNode<String>(
+          'Second',
+          children: <TreeViewNode<String>>[
+            TreeViewNode<String>(
+              'alpha',
+              children: <TreeViewNode<String>>[
+                TreeViewNode<String>('uno'),
+                TreeViewNode<String>('dos'),
+                TreeViewNode<String>('tres'),
+              ],
+            ),
+            TreeViewNode<String>('beta'),
+            TreeViewNode<String>('kappa'),
+          ],
+        ),
+        TreeViewNode<String>(
+          'Third',
+          expanded: true,
+          children: <TreeViewNode<String>>[
+            TreeViewNode<String>('gamma'),
+            TreeViewNode<String>('delta'),
+            TreeViewNode<String>('epsilon'),
+          ],
+        ),
+        TreeViewNode<String>('Fourth'),
+      ];
+
+      await tester.pumpWidget(MaterialApp(
+        home: TreeView<String>(
+          tree: tree,
+          controller: controller,
+          toggleAnimationStyle: AnimationStyle(
+            curve: Curves.easeInOut,
+            duration: Duration.zero,
+          ),
+          treeNodeBuilder: (
+            BuildContext context,
+            TreeViewNode<Object?> node,
+            AnimationStyle animationStyle,
+          ) {
+            final Widget child = GestureDetector(
+              behavior: HitTestBehavior.translucent,
+              onTap: () => controller.toggleNode(node),
+              child: TreeView.defaultTreeNodeBuilder(
+                context,
+                node,
+                animationStyle,
+              ),
+            );
+
+            return child;
+          },
+        ),
+      ));
+
+      expect(find.text('First'), findsOneWidget);
+      expect(find.text('Second'), findsOneWidget);
+      expect(find.text('Third'), findsOneWidget);
+      expect(find.text('Fourth'), findsOneWidget);
+      expect(find.text('alpha'), findsNothing);
+      expect(find.text('beta'), findsNothing);
+      expect(find.text('kappa'), findsNothing);
+      expect(find.text('gamma'), findsOneWidget);
+      expect(find.text('delta'), findsOneWidget);
+      expect(find.text('epsilon'), findsOneWidget);
+      expect(find.text('uno'), findsNothing);
+      expect(find.text('dos'), findsNothing);
+      expect(find.text('tres'), findsNothing);
+
+      await tester.tap(find.text('Second'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('alpha'), findsOneWidget);
+
+      await tester.tap(find.text('alpha'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('uno'), findsOneWidget);
+      expect(find.text('dos'), findsOneWidget);
+      expect(find.text('tres'), findsOneWidget);
+
+      await tester.tap(find.text('alpha'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('uno'), findsNothing);
+      expect(find.text('dos'), findsNothing);
+      expect(find.text('tres'), findsNothing);
+    });
   });
 
   group('TreeViewport', () {