Fix memory leak in DockerPanelRenderer and ToolbarAwareTabBar (#13327)

The DockerPanelRenderer was not disposing the core preference listener.
The ToolbarAwareTabBar was not disposing the TabBarToolbar.

Signed-off-by: Vivien Jovet <[email protected]>
Co-authored-by: Vivien Jovet <[email protected]>

examples/playwright/src/tests/theia-application-shell.test.ts

@@ -0,0 +1,67 @@
+// *****************************************************************************
+// Copyright (C) 2023 Toro Cloud Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+
+import { test } from '@playwright/test';
+import { TheiaApp } from '../theia-app';
+import { TheiaAppLoader } from '../theia-app-loader';
+import { TheiaExplorerView } from '../theia-explorer-view';
+import { TheiaTextEditor } from '../theia-text-editor';
+import { TheiaWelcomeView } from '../theia-welcome-view';
+import { TheiaWorkspace } from '../theia-workspace';
+
+test.describe('Theia Application Shell', () => {
+    test.describe.configure({
+        timeout: 120000
+    });
+
+    let app: TheiaApp;
+
+    test.beforeAll(async ({ playwright, browser }) => {
+        const ws = new TheiaWorkspace(['src/tests/resources/sample-files1']);
+        app = await TheiaAppLoader.load({ playwright, browser }, ws);
+
+        // The welcome view must be closed because the memory leak only occurs when there are
+        // no tabs left open.
+        const welcomeView = new TheiaWelcomeView(app);
+
+        if (await welcomeView.isTabVisible()) {
+            await welcomeView.close();
+        }
+    });
+
+    test.afterAll(async () => {
+        await app.page.close();
+    });
+
+    /**
+     * The aim of this test is to detect memory leaks when opening and closing editors many times.
+     * Remove the skip and run the test, check the logs for any memory leak warnings.
+     * It should take less than 2min to run, if it takes longer than that, just increase the timeout.
+     */
+    test.skip('should open and close a text editor many times', async () => {
+        for (let i = 0; i < 200; i++) {
+            const explorer = await app.openView(TheiaExplorerView);
+
+            const fileStatNode = await explorer.getFileStatNodeByLabel('sample.txt');
+            const contextMenu = await fileStatNode.openContextMenu();
+            await contextMenu.clickMenuItem('Open');
+
+            const textEditor = new TheiaTextEditor('sample.txt', app);
+            await textEditor.waitForVisible();
+
+            await textEditor.close();
+        }
+    });
+});

examples/playwright/src/theia-welcome-view.ts

@@ -0,0 +1,31 @@
+// *****************************************************************************
+// Copyright (C) 2023 Toro Cloud Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+
+import { TheiaApp } from './theia-app';
+import { TheiaView } from './theia-view';
+import { normalizeId } from './util';
+
+const TheiaWelcomeViewData = {
+    tabSelector: normalizeId('#shell-tab-getting.started.widget'),
+    viewSelector: normalizeId('#getting.started.widget'),
+    viewName: 'Welcome'
+};
+
+export class TheiaWelcomeView extends TheiaView {
+
+    constructor(app: TheiaApp) {
+        super(TheiaWelcomeViewData, app);
+    }
+}

packages/core/src/browser/shell/application-shell.ts

@@ -132,16 +132,19 @@ export class DockPanelRenderer implements DockLayout.IRenderer {
             getDynamicTabOptions());
         this.tabBarClasses.forEach(c => tabBar.addClass(c));
         renderer.tabBar = tabBar;
-        tabBar.disposed.connect(() => renderer.dispose());
         renderer.contextMenuPath = SHELL_TABBAR_CONTEXT_MENU;
         tabBar.currentChanged.connect(this.onCurrentTabChanged, this);
-        this.corePreferences.onPreferenceChanged(change => {
+        const prefChangeDisposable = this.corePreferences.onPreferenceChanged(change => {
             if (change.preferenceName === 'workbench.tab.shrinkToFit.enabled' ||
                 change.preferenceName === 'workbench.tab.shrinkToFit.minimumSize' ||
                 change.preferenceName === 'workbench.tab.shrinkToFit.defaultSize') {
                 tabBar.dynamicTabOptions = getDynamicTabOptions();
             }
         });
+        tabBar.disposed.connect(() => {
+            prefChangeDisposable.dispose();
+            renderer.dispose();
+        });
         this.onDidCreateTabBarEmitter.fire(tabBar);
         return tabBar;
     }

packages/core/src/browser/shell/tab-bars.ts

@@ -170,8 +170,8 @@ export class TabBarRenderer extends TabBar.Renderer {
         const hover = this.tabBar && (this.tabBar.orientation === 'horizontal' && this.corePreferences?.['window.tabbar.enhancedPreview'] === 'classic')
             ? { title: title.caption }
             : {
-            onmouseenter: this.handleMouseEnterEvent
-        };
+                onmouseenter: this.handleMouseEnterEvent
+            };
 
         return h.li(
             {
@@ -967,7 +967,7 @@ export class ToolbarAwareTabBar extends ScrollableTabBar {
 
     protected override onBeforeDetach(msg: Message): void {
         if (this.toolbar && this.toolbar.isAttached) {
-            Widget.detach(this.toolbar);
+            this.toolbar.dispose();
         }
         super.onBeforeDetach(msg);
     }