commit a0219e9d8292b70ac3ffa632a9c48cdcee44c9fb
Author: Sebastian Kügler <sebas@kde.org>
Date:   Tue Jun 7 14:35:11 2016 +0200

    Fix crasher on application quit, bump Qt dep to 5.4
    
    Something changed inside QScreen, and now we get invalid objects during
    teardown, where they previously were still accessible. Qt has "new" API
    as of 5.4 so use that and prevent the crash from happening.
    
    REVIEWED-BY:Aleix Pol

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9c834d9..1f6f890 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ include(ECMQtDeclareLoggingCategory)
 include(FeatureSummary)
 include(CheckCXXCompilerFlag)
 
-set(REQUIRED_QT_VERSION 5.2.0)
+set(REQUIRED_QT_VERSION 5.4.0)
 find_package(Qt5 ${REQUIRED_QT_VERSION} CONFIG REQUIRED Core DBus Gui Test X11Extras)
 
 # Wayland backend
diff --git a/backends/qscreen/qscreenconfig.cpp b/backends/qscreen/qscreenconfig.cpp
index c3c69db..156d973 100644
--- a/backends/qscreen/qscreenconfig.cpp
+++ b/backends/qscreen/qscreenconfig.cpp
@@ -39,6 +39,7 @@ QScreenConfig::QScreenConfig(QObject *parent)
     }
     m_blockSignals = false;
     connect(qApp, &QGuiApplication::screenAdded, this, &QScreenConfig::screenAdded);
+    connect(qApp, &QGuiApplication::screenRemoved, this, &QScreenConfig::screenRemoved);
 }
 
 QScreenConfig::~QScreenConfig()
@@ -75,14 +76,12 @@ void QScreenConfig::screenAdded(const QScreen *qscreen)
     qscreenoutput->setId(outputId(qscreen));
     m_outputMap.insert(qscreenoutput->id(), qscreenoutput);
 
-    connect(qscreen, &QObject::destroyed, this, &QScreenConfig::screenDestroyed);
-
     if (!m_blockSignals) {
         Q_EMIT configChanged(toKScreenConfig());
     }
 }
 
-void QScreenConfig::screenDestroyed(QObject *qscreen)
+void QScreenConfig::screenRemoved(QScreen *qscreen)
 {
     qCDebug(KSCREEN_QSCREEN) << "Screen removed" << qscreen << QGuiApplication::screens().count();
     // Find output matching the QScreen object and remove it
diff --git a/backends/qscreen/qscreenconfig.h b/backends/qscreen/qscreenconfig.h
index 1dfcc95..2c80eed 100644
--- a/backends/qscreen/qscreenconfig.h
+++ b/backends/qscreen/qscreenconfig.h
@@ -45,7 +45,7 @@ public:
 
 private Q_SLOTS:
     void screenAdded(const QScreen *qscreen);
-    void screenDestroyed(QObject *qscreen = 0);
+    void screenRemoved(QScreen *qscreen);
 
 Q_SIGNALS:
     void configChanged(const KScreen::ConfigPtr &config);