From eaa3a9d0108cdf692f1686cafefb7b834f0e5af6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C5=82a=C5=BCej=20Szczygie=C5=82?= <spaz16@wp.pl>
Date: Fri, 1 Jan 2016 20:02:42 +0100
Subject: [PATCH] Fix crash because of NULL screen in QXcbWindow

Change-Id: If7bbe3ad1656dadcb098bcd3ece2e7b064eeb44d
Task-number: QTBUG-50081
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>
---
 src/gui/kernel/qwindow.cpp | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index e728d32e4b..83e8777627 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -609,18 +609,16 @@ void QWindow::setParent(QWindow *parent)
     }
 
     QObject::setParent(parent);
-    if (parent)
+
+    QPlatformWindow *parentPlatformWindow = parent ? parent->d_func()->platformWindow : Q_NULLPTR;
+
+    if (parentPlatformWindow)
         d->disconnectFromScreen();
     else
         d->connectToScreen(newScreen);
 
-    if (d->platformWindow) {
-        if (parent && parent->d_func()->platformWindow) {
-            d->platformWindow->setParent(parent->d_func()->platformWindow);
-        } else {
-            d->platformWindow->setParent(0);
-        }
-    }
+    if (d->platformWindow)
+        d->platformWindow->setParent(parentPlatformWindow);
 
     d->parentWindow = parent;