From f78ff8eaa5cc723e1a4d46fc6242e110ad599d96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Wed, 3 Dec 2014 13:10:35 +0100
Subject: [PATCH] Do not emit DecorationSettings::alphaChannelSupportedChanged
 on tear down

The Compositor is destroyed before the Client and Decorations are
destroyed on shutdown. This meant the Decorations reacted needlessly
on the alpha channel supported. E.g. Aurorae recreated the Decoration
and most likely crashed in Qt.

With this change the signal gets disconnected and the Decorations
just don't do anything.
---
 composite.cpp            | 1 +
 composite.h              | 1 +
 decorations/settings.cpp | 8 +++++++-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/composite.cpp b/composite.cpp
index 9983ed3a84..43e5ead886 100644
--- a/composite.cpp
+++ b/composite.cpp
@@ -133,6 +133,7 @@ Compositor::Compositor(QObject* workspace)
 
 Compositor::~Compositor()
 {
+    emit aboutToDestroy();
     finish();
     deleteUnusedSupportProperties();
     delete cm_selection;
diff --git a/composite.h b/composite.h
index 571eaba783..3a2a2a21ac 100644
--- a/composite.h
+++ b/composite.h
@@ -185,6 +185,7 @@ public Q_SLOTS:
 
 Q_SIGNALS:
     void compositingToggled(bool active);
+    void aboutToDestroy();
 
 protected:
     void timerEvent(QTimerEvent *te);
diff --git a/decorations/settings.cpp b/decorations/settings.cpp
index 2e08dcd366..d8bd039a98 100644
--- a/decorations/settings.cpp
+++ b/decorations/settings.cpp
@@ -39,7 +39,7 @@ SettingsImpl::SettingsImpl(KDecoration2::DecorationSettings *parent)
 {
     readSettings();
 
-    connect(Compositor::self(), &Compositor::compositingToggled,
+    auto c = connect(Compositor::self(), &Compositor::compositingToggled,
             parent, &KDecoration2::DecorationSettings::alphaChannelSupportedChanged);
     connect(VirtualDesktopManager::self(), &VirtualDesktopManager::countChanged, this,
         [parent](uint previous, uint current) {
@@ -49,6 +49,12 @@ SettingsImpl::SettingsImpl(KDecoration2::DecorationSettings *parent)
             emit parent->onAllDesktopsAvailableChanged(current > 1);
         }
     );
+    // prevent changes in Decoration due to Compositor being destroyed
+    connect(Compositor::self(), &Compositor::aboutToDestroy, this,
+        [this, c] {
+            disconnect(c);
+        }
+    );
 }
 
 SettingsImpl::~SettingsImpl() = default;