Fix crash in PlacesItem::setUrl()

Connections to lambda slots without context/receiver argument can lead
to crashes, because if the receiver is deleted Qt won't delete the connection
as it normally would when the receiver is specified.

This patch moves the slot from the lambda in PlacesItem (which is not a QObject)
to PlacesItemSignalHandler. This fixes the `dolphinmainwindowtest` crash
we currently have on master, and should also fix bug #394507 which has
the very same stacktrace.

BUG: 394507
FIXED-IN: 18.04.2

3 files changed, 10 insertions, 3 deletions

diff --git a/src/panels/places/placesitem.cpp b/src/panels/places/placesitem.cpp
index ee168e4a3..10b87086c 100644
--- a/src/panels/places/placesitem.cpp
+++ b/src/panels/places/placesitem.cpp
@@ -61,9 +61,7 @@ void PlacesItem::setUrl(const QUrl &url)
     if (dataValue("url").toUrl() != url) {
         delete m_trashDirLister;
         if (url.scheme() == QLatin1String("trash")) {
-            QObject::connect(&Trash::instance(), &Trash::emptinessChanged, [this](bool isTrashEmpty){
-                setIcon(isTrashEmpty ? QStringLiteral("user-trash") : QStringLiteral("user-trash-full"));
-            });
+            QObject::connect(&Trash::instance(), &Trash::emptinessChanged, m_signalHandler.data(), &PlacesItemSignalHandler::onTrashEmptinessChanged);
         }
 
         setDataValue("url", url);
diff --git a/src/panels/places/placesitemsignalhandler.cpp b/src/panels/places/placesitemsignalhandler.cpp
index c85c8336e..b313f838f 100644
--- a/src/panels/places/placesitemsignalhandler.cpp
+++ b/src/panels/places/placesitemsignalhandler.cpp
@@ -51,3 +51,10 @@ void PlacesItemSignalHandler::onTearDownRequested(const QString& udi)
     }
 }
 
+void PlacesItemSignalHandler::onTrashEmptinessChanged(bool isTrashEmpty)
+{
+    if (m_item) {
+        m_item->setIcon(isTrashEmpty ? QStringLiteral("user-trash") : QStringLiteral("user-trash-full"));
+    }
+}
+
diff --git a/src/panels/places/placesitemsignalhandler.h b/src/panels/places/placesitemsignalhandler.h
index 6158d7180..1d0cf9ccd 100644
--- a/src/panels/places/placesitemsignalhandler.h
+++ b/src/panels/places/placesitemsignalhandler.h
@@ -58,6 +58,8 @@ public slots:
 
     void onTearDownRequested(const QString& udi);
 
+    void onTrashEmptinessChanged(bool isTrashEmpty);
+
 signals:
     void tearDownExternallyRequested(const QString& udi);