a11y: Notify of name change when setting window title used as a11y name

When no explicit accessible name is set for a window,
QAccessibleWidget::text uses the window title instead for a
non-minimized window.

Send a QAccessible::NameChanged event when changing the
window title results in a change of the accessible name,
to ensure that the AT-SPI cache on Linux gets updated.

Extend tst_QAccessibility::mainWindowTest() to cover the scenario as well.

Note: The entire test function is skipped on platforms not supporting
window activation, e.g. Wayland.

Fixes: QTBUG-124192
Change-Id: I0fa7f683fb5969d6ba9878f6a506c4f192069799
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

src/widgets/kernel/qwidget.cpp

@@ -6107,6 +6107,13 @@ void QWidget::setWindowTitle(const QString &title)
     if (QWidget::windowTitle() == title && !title.isEmpty() && !title.isNull())
         return;
 
+#if QT_CONFIG(accessibility)
+    QString oldAccessibleName;
+    const QAccessibleInterface *accessible = QAccessible::queryAccessibleInterface(this);
+    if (accessible)
+        oldAccessibleName = accessible->text(QAccessible::Name);
+#endif
+
     Q_D(QWidget);
     d->topData()->caption = title;
     d->setWindowTitle_helper(title);
@@ -6115,6 +6122,13 @@ void QWidget::setWindowTitle(const QString &title)
     QCoreApplication::sendEvent(this, &e);
 
     emit windowTitleChanged(title);
+
+#if QT_CONFIG(accessibility)
+    if (accessible && accessible->text(QAccessible::Name) != oldAccessibleName) {
+        QAccessibleEvent event(this, QAccessible::NameChanged);
+        QAccessible::updateAccessibility(&event);
+    }
+#endif
 }
 
 

tests/auto/other/qaccessibility/tst_qaccessibility.cpp

@@ -966,6 +966,13 @@ void tst_QAccessibility::mainWindowTest()
     QCOMPARE(iface->text(QAccessible::Name), name);
     QCOMPARE(iface->role(), QAccessible::Window);
     QVERIFY(iface->state().active);
+
+    QTestAccessibility::clearEvents();
+    QLatin1String newName = QLatin1String("Main window with updated title");
+    mw->setWindowTitle(newName);
+    QCOMPARE(iface->text(QAccessible::Name), QLatin1String(newName));
+    QAccessibleEvent event(mw, QAccessible::NameChanged);
+    QVERIFY(QTestAccessibility::containsEvent(&event));
     }
     QTestAccessibility::clearEvents();