Drop "<N>" window caption suffix

The current implementation of the `<N>` suffix is still buggy and its
benefits are doubtful. One could argue that visual aids such as window
thumbnails or highlighting the windows are better. On its own, these
numbers don't have strong connections to the windows and can change on
a whim.

autotests/integration/x11_window_test.cpp

@@ -43,7 +43,6 @@ private Q_SLOTS:
     void testFocusInWithWaylandLastActiveWindow();
     void testCaptionChanges();
     void testCaptionWmName();
-    void testCaptionMultipleWindows();
     void testFullscreenWindowGroups();
     void testActivateFocusedWindow();
     void testReentrantMoveResize();
@@ -782,80 +781,6 @@ void X11WindowTest::testCaptionWmName()
     QVERIFY(glxgears.waitForFinished());
 }
 
-void X11WindowTest::testCaptionMultipleWindows()
-{
-    QFETCH_GLOBAL(qreal, scale);
-    kwinApp()->setXwaylandScale(scale);
-
-    // BUG 384760
-    // create first window
-    Test::XcbConnectionPtr c = Test::createX11Connection();
-    QVERIFY(!xcb_connection_has_error(c.get()));
-    const QRect windowGeometry(0, 0, 100, 200);
-    xcb_window_t windowId = xcb_generate_id(c.get());
-    xcb_create_window(c.get(), XCB_COPY_FROM_PARENT, windowId, rootWindow(),
-                      windowGeometry.x(),
-                      windowGeometry.y(),
-                      windowGeometry.width(),
-                      windowGeometry.height(),
-                      0, XCB_WINDOW_CLASS_INPUT_OUTPUT, XCB_COPY_FROM_PARENT, 0, nullptr);
-    xcb_size_hints_t hints;
-    memset(&hints, 0, sizeof(hints));
-    xcb_icccm_size_hints_set_position(&hints, 1, windowGeometry.x(), windowGeometry.y());
-    xcb_icccm_size_hints_set_size(&hints, 1, windowGeometry.width(), windowGeometry.height());
-    xcb_icccm_set_wm_normal_hints(c.get(), windowId, &hints);
-    NETWinInfo info(c.get(), windowId, kwinApp()->x11RootWindow(), NET::Properties(), NET::Properties2());
-    info.setName("foo");
-    xcb_map_window(c.get(), windowId);
-    xcb_flush(c.get());
-
-    QSignalSpy windowCreatedSpy(workspace(), &Workspace::windowAdded);
-    QVERIFY(windowCreatedSpy.wait());
-    X11Window *window = windowCreatedSpy.first().first().value<X11Window *>();
-    QVERIFY(window);
-    QCOMPARE(window->window(), windowId);
-    QCOMPARE(window->caption(), QStringLiteral("foo"));
-
-    // create second window with same caption
-    xcb_window_t w2 = xcb_generate_id(c.get());
-    xcb_create_window(c.get(), XCB_COPY_FROM_PARENT, w2, rootWindow(),
-                      windowGeometry.x(),
-                      windowGeometry.y(),
-                      windowGeometry.width(),
-                      windowGeometry.height(),
-                      0, XCB_WINDOW_CLASS_INPUT_OUTPUT, XCB_COPY_FROM_PARENT, 0, nullptr);
-    xcb_icccm_set_wm_normal_hints(c.get(), w2, &hints);
-    NETWinInfo info2(c.get(), w2, kwinApp()->x11RootWindow(), NET::Properties(), NET::Properties2());
-    info2.setName("foo");
-    info2.setIconName("foo");
-    xcb_map_window(c.get(), w2);
-    xcb_flush(c.get());
-
-    windowCreatedSpy.clear();
-    QVERIFY(windowCreatedSpy.wait());
-    X11Window *window2 = windowCreatedSpy.first().first().value<X11Window *>();
-    QVERIFY(window2);
-    QCOMPARE(window2->window(), w2);
-    QCOMPARE(window2->caption(), QStringLiteral("foo <2>\u200E"));
-    NETWinInfo info3(kwinApp()->x11Connection(), w2, kwinApp()->x11RootWindow(), NET::WMVisibleName | NET::WMVisibleIconName, NET::Properties2());
-    QCOMPARE(QByteArray(info3.visibleName()), QByteArrayLiteral("foo <2>\u200E"));
-    QCOMPARE(QByteArray(info3.visibleIconName()), QByteArrayLiteral("foo <2>\u200E"));
-
-    QSignalSpy captionChangedSpy(window2, &X11Window::captionChanged);
-
-    NETWinInfo info4(c.get(), w2, kwinApp()->x11RootWindow(), NET::Properties(), NET::Properties2());
-    info4.setName("foobar");
-    info4.setIconName("foobar");
-    xcb_map_window(c.get(), w2);
-    xcb_flush(c.get());
-
-    QVERIFY(captionChangedSpy.wait());
-    QCOMPARE(window2->caption(), QStringLiteral("foobar"));
-    NETWinInfo info5(kwinApp()->x11Connection(), w2, kwinApp()->x11RootWindow(), NET::WMVisibleName | NET::WMVisibleIconName, NET::Properties2());
-    QCOMPARE(QByteArray(info5.visibleName()), QByteArray());
-    QTRY_COMPARE(QByteArray(info5.visibleIconName()), QByteArray());
-}
-
 void X11WindowTest::testFullscreenWindowGroups()
 {
     // this test creates an X11 window and puts it to full screen

autotests/integration/xdgshellwindow_test.cpp

@@ -72,7 +72,6 @@ private Q_SLOTS:
     void testHidden();
     void testDesktopFileName();
     void testCaptionSimplified();
-    void testCaptionMultipleWindows();
     void testUnresponsiveWindow_data();
     void testUnresponsiveWindow();
     void testAppMenu();
@@ -708,52 +707,6 @@ void TestXdgShellWindow::testCaptionSimplified()
     QCOMPARE(window->caption(), origTitle.simplified());
 }
 
-void TestXdgShellWindow::testCaptionMultipleWindows()
-{
-    std::unique_ptr<KWayland::Client::Surface> surface(Test::createSurface());
-    std::unique_ptr<Test::XdgToplevel> shellSurface(Test::createXdgToplevelSurface(surface.get()));
-    shellSurface->set_title(QStringLiteral("foo"));
-    auto window = Test::renderAndWaitForShown(surface.get(), QSize(100, 50), Qt::blue);
-    QVERIFY(window);
-    QCOMPARE(window->caption(), QStringLiteral("foo"));
-    QCOMPARE(window->captionNormal(), QStringLiteral("foo"));
-    QCOMPARE(window->captionSuffix(), QString());
-
-    std::unique_ptr<KWayland::Client::Surface> surface2(Test::createSurface());
-    std::unique_ptr<Test::XdgToplevel> shellSurface2(Test::createXdgToplevelSurface(surface2.get()));
-    shellSurface2->set_title(QStringLiteral("foo"));
-    auto c2 = Test::renderAndWaitForShown(surface2.get(), QSize(100, 50), Qt::blue);
-    QVERIFY(c2);
-    QCOMPARE(c2->caption(), QStringLiteral("foo <2>"));
-    QCOMPARE(c2->captionNormal(), QStringLiteral("foo"));
-    QCOMPARE(c2->captionSuffix(), QStringLiteral(" <2>"));
-
-    std::unique_ptr<KWayland::Client::Surface> surface3(Test::createSurface());
-    std::unique_ptr<Test::XdgToplevel> shellSurface3(Test::createXdgToplevelSurface(surface3.get()));
-    shellSurface3->set_title(QStringLiteral("foo"));
-    auto c3 = Test::renderAndWaitForShown(surface3.get(), QSize(100, 50), Qt::blue);
-    QVERIFY(c3);
-    QCOMPARE(c3->caption(), QStringLiteral("foo <3>"));
-    QCOMPARE(c3->captionNormal(), QStringLiteral("foo"));
-    QCOMPARE(c3->captionSuffix(), QStringLiteral(" <3>"));
-
-    std::unique_ptr<KWayland::Client::Surface> surface4(Test::createSurface());
-    std::unique_ptr<Test::XdgToplevel> shellSurface4(Test::createXdgToplevelSurface(surface4.get()));
-    shellSurface4->set_title(QStringLiteral("bar"));
-    auto c4 = Test::renderAndWaitForShown(surface4.get(), QSize(100, 50), Qt::blue);
-    QVERIFY(c4);
-    QCOMPARE(c4->caption(), QStringLiteral("bar"));
-    QCOMPARE(c4->captionNormal(), QStringLiteral("bar"));
-    QCOMPARE(c4->captionSuffix(), QString());
-    QSignalSpy captionChangedSpy(c4, &Window::captionChanged);
-    shellSurface4->set_title(QStringLiteral("foo"));
-    QVERIFY(captionChangedSpy.wait());
-    QCOMPARE(captionChangedSpy.count(), 1);
-    QCOMPARE(c4->caption(), QStringLiteral("foo <4>"));
-    QCOMPARE(c4->captionNormal(), QStringLiteral("foo"));
-    QCOMPARE(c4->captionSuffix(), QStringLiteral(" <4>"));
-}
-
 void TestXdgShellWindow::testUnresponsiveWindow_data()
 {
     QTest::addColumn<QString>("shellInterface"); // see env selection in qwaylandintegration.cpp

src/internalwindow.cpp

@@ -411,17 +411,9 @@ void InternalWindow::doInteractiveResizeSync(const QRectF &rect)
 
 void InternalWindow::updateCaption()
 {
-    const QString oldSuffix = m_captionSuffix;
+    const QString suffix = shortcutCaptionSuffix();
-    const auto shortcut = shortcutCaptionSuffix();
+    if (m_captionSuffix != suffix) {
-    m_captionSuffix = shortcut;
+        m_captionSuffix = suffix;
-    if ((!isSpecialWindow() || isToolbar()) && findWindowWithSameCaption()) {
-        int i = 2;
-        do {
-            m_captionSuffix = shortcut + QLatin1String(" <") + QString::number(i) + QLatin1Char('>');
-            i++;
-        } while (findWindowWithSameCaption());
-    }
-    if (m_captionSuffix != oldSuffix) {
         Q_EMIT captionChanged();
     }
 }
@@ -472,14 +464,8 @@ void InternalWindow::setCaption(const QString &caption)
     }
 
     m_captionNormal = caption;
-
-    const QString oldCaptionSuffix = m_captionSuffix;
-    updateCaption();
-
     Q_EMIT captionNormalChanged();
-    if (m_captionSuffix == oldCaptionSuffix) {
+    Q_EMIT captionChanged();
-        Q_EMIT captionChanged();
-    }
 }
 
 void InternalWindow::markAsMapped()

src/waylandwindow.cpp

@@ -187,34 +187,19 @@ void WaylandWindow::updateResourceName()
 
 void WaylandWindow::updateCaption()
 {
-    const QString oldSuffix = m_captionSuffix;
+    const QString suffix = shortcutCaptionSuffix();
-    const auto shortcut = shortcutCaptionSuffix();
+    if (m_captionSuffix != suffix) {
-    m_captionSuffix = shortcut;
+        m_captionSuffix = suffix;
-    if ((!isSpecialWindow() || isToolbar()) && findWindowWithSameCaption()) {
-        int i = 2;
-        do {
-            m_captionSuffix = shortcut + QLatin1String(" <") + QString::number(i) + QLatin1Char('>');
-            i++;
-        } while (findWindowWithSameCaption());
-    }
-    if (m_captionSuffix != oldSuffix) {
         Q_EMIT captionChanged();
     }
 }
 
 void WaylandWindow::setCaption(const QString &caption)
 {
-    const QString oldNormal = m_captionNormal;
+    const QString simplified = caption.simplified();
-    const QString oldSuffix = m_captionSuffix;
+    if (m_captionNormal != simplified) {
-
+        m_captionNormal = simplified;
-    m_captionNormal = caption.simplified();
-    updateCaption();
-
-    if (m_captionNormal != oldNormal) {
         Q_EMIT captionNormalChanged();
-    }
-    if (m_captionSuffix == oldSuffix) {
-        // Don't emit caption change twice it already got emitted by the changing suffix.
         Q_EMIT captionChanged();
     }
 }
@@ -297,7 +282,6 @@ void WaylandWindow::markAsMapped()
 {
     if (Q_UNLIKELY(!ready_for_painting)) {
         setupCompositing();
-        updateCaption();
         setReadyForPainting();
     }
 }

src/window.cpp

@@ -3080,14 +3080,6 @@ QString Window::shortcutCaptionSuffix() const
     return QLatin1String(" {") + shortcut().toString() + QLatin1Char('}');
 }
 
-Window *Window::findWindowWithSameCaption() const
-{
-    auto fetchNameInternalPredicate = [this](const Window *cl) {
-        return (!cl->isSpecialWindow() || cl->isToolbar()) && cl != this && cl->captionNormal() == captionNormal() && cl->captionSuffix() == captionSuffix();
-    };
-    return workspace()->findWindow(fetchNameInternalPredicate);
-}
-
 QString Window::caption() const
 {
     QString cap = captionNormal() + captionSuffix();

src/window.h

@@ -1708,12 +1708,6 @@ protected:
     QString shortcutCaptionSuffix() const;
     virtual void updateCaption() = 0;
 
-    /**
-     * Looks for another Window with same captionNormal and captionSuffix.
-     * If no such Window exists @c nullptr is returned.
-     */
-    Window *findWindowWithSameCaption() const;
-
     void startShadeHoverTimer();
     void startShadeUnhoverTimer();
     void shadeHover();

src/x11window.cpp

@@ -644,8 +644,6 @@ bool X11Window::manage(xcb_window_t w, bool isMapped)
     setupWindowRules();
     connect(this, &X11Window::windowClassChanged, this, &X11Window::evaluateWindowRules);
 
-    updateCaption(); // in case the window type has been changed by a window rule and <N> has been dropped
-
     if (Xcb::Extensions::self()->isShapeAvailable()) {
         xcb_shape_select_input(kwinApp()->x11Connection(), window(), true);
     }
@@ -2340,7 +2338,6 @@ void X11Window::setCaption(const QString &_s, bool force)
     }
     cap_normal = s;
 
-    bool reset_name = force;
     bool was_suffix = (!cap_suffix.isEmpty());
     cap_suffix.clear();
     QString machine_suffix;
@@ -2351,16 +2348,7 @@ void X11Window::setCaption(const QString &_s, bool force)
     }
     QString shortcut_suffix = shortcutCaptionSuffix();
     cap_suffix = machine_suffix + shortcut_suffix;
-    if ((!isSpecialWindow() || isToolbar()) && findWindowWithSameCaption()) {
+    if ((was_suffix && cap_suffix.isEmpty()) || force) {
-        int i = 2;
-        do {
-            cap_suffix = machine_suffix + QLatin1String(" <") + QString::number(i) + QLatin1Char('>') + LRM;
-            i++;
-        } while (findWindowWithSameCaption());
-        info->setVisibleName(caption().toUtf8().constData());
-        reset_name = false;
-    }
-    if ((was_suffix && cap_suffix.isEmpty()) || reset_name) {
         // If it was new window, it may have old value still set, if the window is reused
         info->setVisibleName("");
         info->setVisibleIconName("");