fix(app:linux): prevent infinite loop on file backstage

browser/src/app/ViewLayoutMultiPage.ts

@@ -176,6 +176,11 @@ class ViewLayoutMultiPage extends ViewLayoutNewBase {
 
 	protected refreshVisibleAreaRectangle(): void {
 		const documentAnchor = this.getDocumentAnchorSection();
+
+		// When the document container is hidden (e.g. BackstageView in CODA), the
+		// anchor section has zero size - bail out to avoid an infinite retry loop.
+		if (documentAnchor.size[0] <= 0 || documentAnchor.size[1] <= 0) return;
+
 		const view = cool.SimpleRectangle.fromCorePixels([
 			this.scrollProperties.viewX,
 			this.scrollProperties.viewY,

qt/test/lib/file-dialog.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright the Collabora Online contributors.
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+import { join } from 'path';
+import * as webview from './webview.js';
+
+/**
+ * Open a file from the test fixtures directory via the native Qt file dialog.
+ *
+ * Triggers .uno:Open, fills the filename field, clicks Open, switches to
+ * the new WebView, and waits for the document to finish loading.
+ */
+export async function openFixture(
+	webEngine: WebdriverIO.Browser,
+	native: WebdriverIO.Browser,
+	fileName: string,
+): Promise<void> {
+	// Use setTimeout so execute() returns before the modal dialog blocks.
+	await webEngine.execute(() => {
+		setTimeout(() => {
+			window.postMobileMessage('uno .uno:Open');
+		}, 100);
+	});
+
+	const fileNameField = await native.$(
+		'//*[@accessibility-id="QApplication.QFileDialog.fileNameEdit"]',
+	);
+	await fileNameField.waitForExist({ timeout: 10000 });
+
+	const filePath = join(process.env.CODA_QT_TEST_DOCUMENTS_DIR!, fileName);
+	await fileNameField.setValue(filePath);
+
+	const openBtn = await native.$(
+		'//*[@accessibility-id="QApplication.QFileDialog.buttonBox.QPushButton"]',
+	);
+	await openBtn.waitForExist({ timeout: 5000 });
+	await openBtn.click();
+
+	await webview.switchToNewWebView(webEngine);
+
+	await (webEngine as any).waitForCondition(
+		() =>
+			typeof app !== 'undefined' &&
+			app.map &&
+			app.map._docLoaded === true,
+		{
+			timeout: 45000,
+			timeoutMsg: `Document did not load after opening ${fileName}`,
+		},
+	);
+}

qt/test/specs/multipage-backstage.spec.ts

@@ -0,0 +1,98 @@
+/*
+ * Copyright the Collabora Online contributors.
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+import { openFixture } from '../lib/file-dialog.js';
+
+// Regression test for https://github.com/CollaboraOnline/online/issues/15291
+//
+// When BackstageView is shown while multi-page view is active, hiding
+// #document-container triggers ResizeObservers that shrink the canvas to
+// zero. ViewLayoutMultiPage.refreshVisibleAreaRectangle() then enters an
+// infinite retry loop (no page rectangles intersect a zero-sized viewport),
+// making the UI completely unresponsive.
+describe('Multi-page view backstage (issue #15291)', () => {
+	it('should not freeze when opening backstage in multi-page view', async function () {
+		await openFixture(browser.webEngine, browser.native, 'scrolling.odt');
+
+		// Enable multi-page view.
+		await browser.webEngine.execute(() => {
+			app.dispatcher.dispatch('multipageview');
+		});
+
+		// Wait for multi-page view to be active with multiple pages.
+		await browser.webEngine.waitForCondition(
+			() => {
+				const layout = app.activeDocument?.activeLayout;
+				return !!(
+					layout?.type === 'ViewLayoutMultiPage' &&
+					layout.documentRectangles &&
+					layout.documentRectangles.length > 1
+				);
+			},
+			{
+				timeout: 15000,
+				timeoutMsg:
+					'Multi-page view did not activate with multiple pages',
+			},
+		);
+
+		// Wait for layout tasks to settle before triggering backstage.
+		await browser.webEngine.waitForCondition(
+			() => !app.layoutingService.hasTasksPending(),
+			{ timeout: 10000, timeoutMsg: 'Layout tasks did not settle' },
+		);
+
+		// Show the backstage view (same as clicking the File tab).
+		// Without the fix this causes an infinite layout task loop.
+		await browser.webEngine.execute(() => {
+			app.map.backstageView!.show();
+		});
+
+		// Verify layout tasks drain. Without the fix, hasTasksPending()
+		// stays true forever due to the infinite retry loop in
+		// refreshVisibleAreaRectangle().
+		await browser.webEngine.waitForCondition(
+			() => !app.layoutingService.hasTasksPending(),
+			{
+				timeout: 5000,
+				timeoutMsg:
+					'Layout tasks did not drain - infinite loop detected (issue #15291)',
+			},
+		);
+
+		// Close the backstage.
+		await browser.webEngine.execute(() => {
+			app.map.backstageView!.hide();
+		});
+
+		// Verify multi-page view recovered after backstage is closed.
+		await browser.webEngine.waitForCondition(
+			() => {
+				const container = document.getElementById(
+					'document-container',
+				);
+				if (!container || container.classList.contains('hidden'))
+					return false;
+
+				const layout = app.activeDocument?.activeLayout;
+				if (!layout || layout.type !== 'ViewLayoutMultiPage')
+					return false;
+
+				const vr = layout.viewedRectangle;
+				return !!(vr && vr.pWidth > 0 && vr.pHeight > 0);
+			},
+			{
+				timeout: 15000,
+				timeoutMsg:
+					'Multi-page view did not recover after backstage',
+			},
+		);
+	});
+});

qt/test/specs/open-file.spec.ts

@@ -8,46 +8,11 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-import { join } from 'path';
-import * as webview from '../lib/webview.js';
+import { openFixture } from '../lib/file-dialog.js';
 
 describe('Open existing file', () => {
 	it('should open a .odt file via the native file dialog', async function () {
-		// Send the UNO Open command via the bridge. Use setTimeout so
-		// execute() returns before the modal dialog blocks the WebView.
-		await browser.webEngine.execute(() => {
-			setTimeout(() => {
-				window.postMobileMessage('uno .uno:Open');
-			}, 100);
-		});
-
-		// Wait for the filename field; accessibility-id is locale-stable.
-		const fileNameField = await browser.native.$(
-			'//*[@accessibility-id="QApplication.QFileDialog.fileNameEdit"]',
-		);
-		await fileNameField.waitForExist({ timeout: 10000 });
-
-		const filePath = join(process.env.CODA_QT_TEST_DOCUMENTS_DIR!, 'simple.odt');
-		await fileNameField.setValue(filePath);
-
-		// First QPushButton is "Open"
-		const openBtn = await browser.native.$(
-			'//*[@accessibility-id="QApplication.QFileDialog.buttonBox.QPushButton"]',
-		);
-		await openBtn.waitForExist({ timeout: 5000 });
-		await openBtn.click();
-
-		await webview.switchToNewWebView(browser.webEngine);
-
-		// Use _docLoaded; opening a file may not auto-focus the cursor.
-		await browser.webEngine.waitForCondition(
-			() =>
-				typeof app !== 'undefined' && app.map && app.map._docLoaded === true,
-			{
-				timeout: 45000,
-				timeoutMsg: 'Document editor did not load after opening file',
-			},
-		);
+		await openFixture(browser.webEngine, browser.native, 'simple.odt');
 
 		const state = await browser.webEngine.execute(() => ({
 			docLoaded: app.map._docLoaded,

qt/test/wdio.d.ts

@@ -31,5 +31,23 @@ declare const app: {
 	map: {
 		_docLoaded: boolean;
 		getDocType(): string;
+		backstageView?: {
+			show(): void;
+			hide(): void;
+			toggle(): void;
+		};
+	};
+	dispatcher: {
+		dispatch(action: string): void;
+	};
+	activeDocument?: {
+		activeLayout?: {
+			type: string;
+			documentRectangles?: Array<unknown>;
+			viewedRectangle?: { pWidth: number; pHeight: number };
+		};
+	};
+	layoutingService: {
+		hasTasksPending(): boolean;
 	};
 };