xdg-shell v5,v6 shell integrations: Fix crash when showing popups

If a popup was shown without any input events happening first, it would cause
nullptr dereferences in both xdg-shell v5 and v6.

Fixes crashes in:

- tst_QAccessibility::comboBoxTest
- tst_QAccessibility::menuTest
- tst_QWindow::touchInterruptedByPopup
- tst_QFocusEvent::checkReason_Popup

Task-number: QTBUG-67150
Change-Id: Ib3e06326f71e4ab5f74727cb4f79626a21c34d55
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

4 files changed, 8 insertions, 7 deletions

diff --git a/src/client/qwaylandxdgshell.cpp b/src/client/qwaylandxdgshell.cpp
index 8b252b953..9a34e72dd 100644
--- a/src/client/qwaylandxdgshell.cpp
+++ b/src/client/qwaylandxdgshell.cpp
@@ -73,12 +73,11 @@ QWaylandXdgSurface *QWaylandXdgShell::createXdgSurface(QWaylandWindow *window)
     return new QWaylandXdgSurface(this, window);
 }
 
-QWaylandXdgPopup *QWaylandXdgShell::createXdgPopup(QWaylandWindow *window)
+QWaylandXdgPopup *QWaylandXdgShell::createXdgPopup(QWaylandWindow *window, QWaylandInputDevice *inputDevice)
 {
     QWaylandWindow *parentWindow = m_popups.empty() ? window->transientParent() : m_popups.last();
     ::wl_surface *parentSurface = parentWindow->object();
 
-    QWaylandInputDevice *inputDevice = window->display()->lastInputDevice();
     if (m_popupSerial == 0)
         m_popupSerial = inputDevice->serial();
     ::wl_seat *seat = inputDevice->wl_seat();
diff --git a/src/client/qwaylandxdgshell_p.h b/src/client/qwaylandxdgshell_p.h
index afbd9c591..761f25218 100644
--- a/src/client/qwaylandxdgshell_p.h
+++ b/src/client/qwaylandxdgshell_p.h
@@ -79,7 +79,7 @@ public:
     ~QWaylandXdgShell() override;
 
     QWaylandXdgSurface *createXdgSurface(QWaylandWindow *window);
-    QWaylandXdgPopup *createXdgPopup(QWaylandWindow *window);
+    QWaylandXdgPopup *createXdgPopup(QWaylandWindow *window, QWaylandInputDevice *inputDevice);
 
 private:
     void xdg_shell_ping(uint32_t serial) override;
diff --git a/src/client/qwaylandxdgshellintegration.cpp b/src/client/qwaylandxdgshellintegration.cpp
index 5fa4385d6..ee72c2d52 100644
--- a/src/client/qwaylandxdgshellintegration.cpp
+++ b/src/client/qwaylandxdgshellintegration.cpp
@@ -74,8 +74,9 @@ bool QWaylandXdgShellIntegration::initialize(QWaylandDisplay *display)
 
 QWaylandShellSurface *QWaylandXdgShellIntegration::createShellSurface(QWaylandWindow *window)
 {
-    if (window->window()->type() == Qt::WindowType::Popup)
-        return m_xdgShell->createXdgPopup(window);
+    QWaylandInputDevice *inputDevice = window->display()->lastInputDevice();
+    if (window->window()->type() == Qt::WindowType::Popup && inputDevice)
+        return m_xdgShell->createXdgPopup(window, inputDevice);
     else
         return m_xdgShell->createXdgSurface(window);
 }
diff --git a/src/client/qwaylandxdgshellv6.cpp b/src/client/qwaylandxdgshellv6.cpp
index c89c8316f..a166a3bc9 100644
--- a/src/client/qwaylandxdgshellv6.cpp
+++ b/src/client/qwaylandxdgshellv6.cpp
@@ -165,8 +165,9 @@ void QWaylandXdgSurfaceV6::setAppId(const QString &appId)
 
 void QWaylandXdgSurfaceV6::setType(Qt::WindowType type, QWaylandWindow *transientParent)
 {
-    if ((type == Qt::Popup || type == Qt::ToolTip) && transientParent) {
-        setPopup(transientParent, m_window->display()->lastInputDevice(), m_window->display()->lastInputSerial(), type == Qt::Popup);
+    QWaylandDisplay *display = m_window->display();
+    if ((type == Qt::Popup || type == Qt::ToolTip) && transientParent && display->lastInputDevice()) {
+        setPopup(transientParent, display->lastInputDevice(), display->lastInputSerial(), type == Qt::Popup);
     } else {
         setToplevel();
         if (transientParent) {