Fix disposable leak in TOCTree by properly tracking stylesheet

Co-authored-by: rzhao271 <[email protected]>

Author: Copilot

src/vs/workbench/contrib/preferences/browser/tocTree.ts

@@ -214,7 +214,11 @@ export class TOCTree extends WorkbenchObjectTree<SettingsTreeGroupElement> {
 		@IHoverService hoverService: IHoverService,
 		@IInstantiationService instantiationService: IInstantiationService,
 	) {
-		// test open mode
+		// Create a disposable store to track resources created before super()
+		const disposableStore = new DisposableStore();
+
+		// Create the style element and track it for disposal
+		const styleElement = domStylesheetsJs.createStyleSheet(container, undefined, disposableStore);
 
 		const filter = instantiationService.createInstance(SettingsTreeFilter, viewState);
 		const options: IWorkbenchObjectTreeOptions<SettingsTreeGroupElement, void> = {
@@ -225,7 +229,7 @@ export class TOCTree extends WorkbenchObjectTree<SettingsTreeGroupElement> {
 					return e.id;
 				}
 			},
-			styleController: id => new DefaultStyleController(domStylesheetsJs.createStyleSheet(container), id),
+			styleController: id => new DefaultStyleController(styleElement, id),
 			accessibilityProvider: instantiationService.createInstance(SettingsAccessibilityProvider),
 			collapseByDefault: true,
 			horizontalScrolling: false,
@@ -245,6 +249,9 @@ export class TOCTree extends WorkbenchObjectTree<SettingsTreeGroupElement> {
 			configurationService,
 		);
 
+		// Register the disposable store to be disposed when the tree is disposed
+		this.disposables.add(disposableStore);
+
 		this.style(getListStyles({
 			listBackground: editorBackground,
 			listFocusOutline: focusBorder,

src/vs/workbench/contrib/preferences/test/browser/tocTree.test.ts

@@ -0,0 +1,79 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import assert from 'assert';
+import { ensureNoDisposablesAreLeakedInTestSuite } from '../../../../../base/test/common/utils.js';
+import { TOCTree, TOCTreeModel } from '../../browser/tocTree.js';
+import { TestInstantiationService } from '../../../../../platform/instantiation/test/common/instantiationServiceMock.js';
+import { IListService, ListService } from '../../../../../platform/list/browser/listService.js';
+import { IContextKeyService } from '../../../../../platform/contextkey/common/contextkey.js';
+import { ContextKeyService } from '../../../../../platform/contextkey/browser/contextKeyService.js';
+import { IConfigurationService } from '../../../../../platform/configuration/common/configuration.js';
+import { TestConfigurationService } from '../../../../../platform/configuration/test/common/testConfigurationService.js';
+import { IHoverService } from '../../../../../platform/hover/browser/hover.js';
+import { NullHoverService } from '../../../../../platform/hover/test/browser/nullHoverService.js';
+import { ConfigurationTarget } from '../../../../../platform/configuration/common/configuration.js';
+import { ISettingsEditorViewState } from '../../browser/settingsTreeModels.js';
+import { toDisposable } from '../../../../../base/common/lifecycle.js';
+import { mainWindow } from '../../../../../base/browser/window.js';
+import { IWorkbenchEnvironmentService } from '../../../../services/environment/common/environmentService.js';
+import { mock } from '../../../../../base/test/common/mock.js';
+
+suite('TOCTree', () => {
+	const store = ensureNoDisposablesAreLeakedInTestSuite();
+	let instantiationService: TestInstantiationService;
+	let container: HTMLElement;
+
+	setup(() => {
+		container = document.createElement('div');
+		mainWindow.document.body.appendChild(container);
+		store.add(toDisposable(() => container.remove()));
+
+		instantiationService = store.add(new TestInstantiationService());
+
+		// Set up required services
+		instantiationService.stub(IListService, store.add(new ListService()));
+		instantiationService.stub(IContextKeyService, store.add(instantiationService.createInstance(ContextKeyService)));
+		instantiationService.stub(IConfigurationService, new TestConfigurationService());
+		instantiationService.stub(IHoverService, NullHoverService);
+		instantiationService.stub(IWorkbenchEnvironmentService, new class extends mock<IWorkbenchEnvironmentService>() {
+			override remoteAuthority = undefined;
+		});
+	});
+
+	test('TOCTree should not leak disposables', () => {
+		const viewState: ISettingsEditorViewState = {
+			settingsTarget: ConfigurationTarget.USER_LOCAL,
+			tagFilters: undefined,
+			featureFilters: undefined,
+			extensionFilters: undefined,
+			idFilters: undefined,
+			languageFilter: undefined,
+			filterToCategory: undefined
+		};
+
+		const tree = store.add(instantiationService.createInstance(TOCTree, container, viewState));
+		assert.ok(tree, 'TOCTree should be created');
+
+		// Dispose the tree to verify no leaks
+		tree.dispose();
+	});
+
+	test('TOCTreeModel should be disposable', () => {
+		const viewState: ISettingsEditorViewState = {
+			settingsTarget: ConfigurationTarget.USER_LOCAL,
+			tagFilters: undefined,
+			featureFilters: undefined,
+			extensionFilters: undefined,
+			idFilters: undefined,
+			languageFilter: undefined,
+			filterToCategory: undefined
+		};
+
+		const model = instantiationService.createInstance(TOCTreeModel, viewState);
+		assert.ok(model, 'TOCTreeModel should be created');
+		// TOCTreeModel doesn't implement IDisposable, so just verify it's created successfully
+	});
+});