From 8d8ac4c8d5a399df7815bda6955643ee77be48ac Mon Sep 17 00:00:00 2001
From: Cheng-Hsuan Tsai <webcat@google.com>
Date: Thu, 23 Apr 2026 03:24:04 +0000
Subject: [PATCH] fix(cdk/tree): enter/space key on child node should not
 toggle parent node expansion

---
 goldens/cdk/tree/index.api.md |  2 +-
 src/cdk/tree/toggle.ts        | 10 ++++++----
 src/cdk/tree/tree.spec.ts     | 28 ++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/goldens/cdk/tree/index.api.md b/goldens/cdk/tree/index.api.md
index 3f3e5912dce3..42dbb07f3828 100644
--- a/goldens/cdk/tree/index.api.md
+++ b/goldens/cdk/tree/index.api.md
@@ -272,7 +272,7 @@ export class CdkTreeNodeToggle<T, K = T> {
     static ngAcceptInputType_recursive: unknown;
     recursive: boolean;
     // (undocumented)
-    _toggle(): void;
+    _toggle(event: Event): void;
     // (undocumented)
     protected _tree: CdkTree<T, K>;
     // (undocumented)
diff --git a/src/cdk/tree/toggle.ts b/src/cdk/tree/toggle.ts
index 3d18948f59a3..a6f06fa14990 100644
--- a/src/cdk/tree/toggle.ts
+++ b/src/cdk/tree/toggle.ts
@@ -16,9 +16,9 @@ import {CdkTree, CdkTreeNode} from './tree';
 @Directive({
   selector: '[cdkTreeNodeToggle]',
   host: {
-    '(click)': '_toggle(); $event.stopPropagation();',
-    '(keydown.Enter)': '_toggle(); $event.preventDefault();',
-    '(keydown.Space)': '_toggle(); $event.preventDefault();',
+    '(click)': '_toggle($event)',
+    '(keydown.Enter)': '_toggle($event); $event.preventDefault();',
+    '(keydown.Space)': '_toggle($event); $event.preventDefault();',
     'tabindex': '-1',
   },
 })
@@ -34,7 +34,9 @@ export class CdkTreeNodeToggle<T, K = T> {
   //
   // Focus this node with expanding or collapsing it. This ensures that the active node will always
   // be visible when expanding and collapsing.
-  _toggle(): void {
+  _toggle(event: Event): void {
+    event.stopPropagation();
+
     this.recursive
       ? this._tree.toggleDescendants(this._treeNode.data)
       : this._tree.toggle(this._treeNode.data);
diff --git a/src/cdk/tree/tree.spec.ts b/src/cdk/tree/tree.spec.ts
index ae6fe563e1cc..014e897cd72e 100644
--- a/src/cdk/tree/tree.spec.ts
+++ b/src/cdk/tree/tree.spec.ts
@@ -966,6 +966,34 @@ describe('CdkTree', () => {
           [`topping_3 - cheese_3 + base_3`],
         );
       });
+
+      it('should not collapse parent when child is toggled via keyboard', () => {
+        component.toggleRecursively = false;
+        fixture.changeDetectorRef.markForCheck();
+        let data = dataSource.data;
+        const child = dataSource.addChild(data[1], false);
+        dataSource.addChild(child, false);
+        fixture.detectChanges();
+
+        // Expand parent
+        (getNodes(treeElement)[1] as HTMLElement).click();
+        fixture.detectChanges();
+
+        expect(component.tree.isExpanded(data[1])).toBe(true);
+
+        // Focus child node (which is now at index 2)
+        const childNode = getNodes(treeElement)[2] as HTMLElement;
+
+        // Simulate Enter key on child node
+        const event = createKeyboardEvent('keydown', undefined, 'Enter');
+        childNode.dispatchEvent(event);
+        fixture.detectChanges();
+
+        // Verify parent is still expanded
+        expect(component.tree.isExpanded(data[1]))
+          .withContext('Parent should remain expanded')
+          .toBe(true);
+      });
     });
 
     describe('nested tree with array data source', () => {