[wayland] Destroy all ClientConnections on tear down

Ensures that all Wayland objects are destroyed and the cleanup handling
is performed before tearing down the Compositor. This fixes for example
a crash if a Surface with a Shadow is still around at tear down.

autotests/wayland/kwin_wayland_test.cpp

@@ -73,7 +73,7 @@ WaylandTestApplication::~WaylandTestApplication()
         }
         waylandServer()->destroyXWaylandConnection();
     }
-    waylandServer()->destroyInternalConnection();
+    waylandServer()->terminateClientConnections();
     destroyCompositor();
 }
 

main_wayland.cpp

@@ -97,7 +97,7 @@ ApplicationWayland::~ApplicationWayland()
         }
         waylandServer()->destroyXWaylandConnection();
     }
-    waylandServer()->destroyInternalConnection();
+    waylandServer()->terminateClientConnections();
     destroyCompositor();
 }
 

wayland_server.cpp

@@ -91,6 +91,16 @@ void WaylandServer::destroyInternalConnection()
     }
 }
 
+void WaylandServer::terminateClientConnections()
+{
+    destroyInternalConnection();
+    destroyInputMethodConnection();
+    const auto connections = m_display->connections();
+    for (auto it = connections.begin(); it != connections.end(); ++it) {
+        (*it)->destroy();
+    }
+}
+
 void WaylandServer::init(const QByteArray &socketName, InitalizationFlags flags)
 {
     m_initFlags = flags;

wayland_server.h

@@ -72,6 +72,7 @@ public:
     virtual ~WaylandServer();
     void init(const QByteArray &socketName = QByteArray(), InitalizationFlags flags = InitalizationFlag::NoOptions);
     void initOutputs();
+    void terminateClientConnections();
 
     KWayland::Server::Display *display() {
         return m_display;
@@ -123,7 +124,6 @@ public:
     bool isScreenLocked() const;
 
     void createInternalConnection();
-    void destroyInternalConnection();
     void initWorkspace();
 
     KWayland::Server::ClientConnection *xWaylandConnection() const {
@@ -156,6 +156,7 @@ Q_SIGNALS:
 
 private:
     quint16 createClientId(KWayland::Server::ClientConnection *c);
+    void destroyInternalConnection();
     KWayland::Server::Display *m_display = nullptr;
     KWayland::Server::CompositorInterface *m_compositor = nullptr;
     KWayland::Server::SeatInterface *m_seat = nullptr;