From 72efefaa4955aca2393d1573d3e6dfb43e25bd1d Mon Sep 17 00:00:00 2001
From: Klondike Dragon <klondikedragon@gmail.com>
Date: Tue, 19 Mar 2024 22:49:45 -0600
Subject: [PATCH] TreeViewItem.from should set parent properly

* Ensures that deep copies of a tree have proper linkage.
* Adds a unit test to verify that the parent prop is set properly.
---
 lib/src/controls/navigation/tree_view.dart | 45 ++++++++++++---------
 test/tree_view_test.dart                   | 47 ++++++++++++++++++++++
 2 files changed, 72 insertions(+), 20 deletions(-)

diff --git a/lib/src/controls/navigation/tree_view.dart b/lib/src/controls/navigation/tree_view.dart
index c7090992c..95c353a74 100644
--- a/lib/src/controls/navigation/tree_view.dart
+++ b/lib/src/controls/navigation/tree_view.dart
@@ -184,25 +184,30 @@ class TreeViewItem with Diagnosticable {
   /// its child items. Useful if you want to have multiple trees with the
   /// same items, but with different UX states (e.g., selection, visibility,
   /// etc.).
-  TreeViewItem.from(TreeViewItem source)
-      : this(
-          key: source.key,
-          leading: source.leading,
-          content: source.content,
-          value: source.value,
-          children: source.children.map(TreeViewItem.from).toList(),
-          collapsable: source.collapsable,
-          expanded: source.expanded,
-          selected: source.selected,
-          onInvoked: source.onInvoked,
-          onExpandToggle: source.onExpandToggle,
-          backgroundColor: source.backgroundColor,
-          autofocus: source.autofocus,
-          focusNode: source.focusNode,
-          semanticLabel: source.semanticLabel,
-          loadingWidget: source.loadingWidget,
-          lazy: source.lazy,
-        );
+  factory TreeViewItem.from(TreeViewItem source) {
+    final newItem = TreeViewItem(
+      key: source.key,
+      leading: source.leading,
+      content: source.content,
+      value: source.value,
+      children: source.children.map(TreeViewItem.from).toList(),
+      collapsable: source.collapsable,
+      expanded: source.expanded,
+      selected: source.selected,
+      onInvoked: source.onInvoked,
+      onExpandToggle: source.onExpandToggle,
+      backgroundColor: source.backgroundColor,
+      autofocus: source.autofocus,
+      focusNode: source.focusNode,
+      semanticLabel: source.semanticLabel,
+      loadingWidget: source.loadingWidget,
+      lazy: source.lazy,
+    );
+    for (final c in newItem.children) {
+      c._parent = newItem;
+    }
+    return newItem;
+  }
 
   /// Whether this node is expandable
   bool get isExpandable {
@@ -385,7 +390,7 @@ extension TreeViewItemCollection on List<TreeViewItem> {
     if (isNotEmpty) {
       final list = <TreeViewItem>[];
       final anyExpandableSiblings = any((i) => i.isExpandable);
-      for (final item in [...this]) {
+      for (final item in this) {
         item
           .._parent = parent
           .._anyExpandableSiblings = anyExpandableSiblings;
diff --git a/test/tree_view_test.dart b/test/tree_view_test.dart
index f36c700e1..5cf30f318 100644
--- a/test/tree_view_test.dart
+++ b/test/tree_view_test.dart
@@ -29,6 +29,53 @@ void main() {
     await tester.pumpWidget(wrapApp(child: TreeView(items: items)));
 
     expect(itemOne.parent, isNotNull);
+    expect(itemOne.parent, items[0]);
     expect(itemOne.parent?.selected, null);
   });
+
+  testWidgets('TreeViewItem deep copy rebuilds parent linkage',
+      (WidgetTester tester) async {
+    final items = [
+      TreeViewItem(
+        content: const Text('Parent item'),
+        children: [
+          TreeViewItem(
+            content: const Text('Item 1'),
+            children: [
+              TreeViewItem(
+                content: const Text('Subitem 1'),
+              ),
+              TreeViewItem(
+                content: const Text('Subitem 2'),
+              ),
+            ],
+          ),
+          TreeViewItem(
+            content: const Text('Item 2'),
+          ),
+          TreeViewItem(
+            content: const Text('Item 3'),
+          ),
+        ],
+      ),
+    ];
+
+    await tester.pumpWidget(wrapApp(child: TreeView(items: items)));
+    expect(items[0].parent, isNull);
+    expect(items[0].children[0].parent, items[0]);
+    expect(items[0].children[1].parent, items[0]);
+    expect(items[0].children[2].parent, items[0]);
+    expect(items[0].children[0].children[0].parent, items[0].children[0]);
+    expect(items[0].children[0].children[1].parent, items[0].children[0]);
+
+    final itemsCopy = items.map(TreeViewItem.from).toList();
+    expect(itemsCopy[0].parent, isNull);
+    expect(itemsCopy[0].children[0].parent, itemsCopy[0]);
+    expect(itemsCopy[0].children[1].parent, itemsCopy[0]);
+    expect(itemsCopy[0].children[2].parent, itemsCopy[0]);
+    expect(
+        itemsCopy[0].children[0].children[0].parent, itemsCopy[0].children[0]);
+    expect(
+        itemsCopy[0].children[0].children[1].parent, itemsCopy[0].children[0]);
+  });
 }