stylesheets: Don't fail silently with invalid background-images

Print a qWarning, otherwise this is very hard to notice

Change-Id: I882f97583071e786d5aa06f6eeb485da4fc646db
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: David Faure <david.faure@kdab.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/widgets/styles/qstylesheetstyle.cpp b/src/widgets/styles/qstylesheetstyle.cpp
index e34bae64ce..5c9d19a49d 100644
--- a/src/widgets/styles/qstylesheetstyle.cpp
+++ b/src/widgets/styles/qstylesheetstyle.cpp
@@ -44,6 +44,7 @@
 
 #include "private/qcssutil_p.h"
 #include <qdebug.h>
+#include <qdir.h>
 #include <qapplication.h>
 #if QT_CONFIG(menu)
 #include <qmenu.h>
@@ -952,8 +953,12 @@ QRenderRule::QRenderRule(const QVector<Declaration> &declarations, const QObject
     Attachment attachment = Attachment_Scroll;
     origin = Origin_Padding;
     Origin clip = Origin_Border;
-    if (v.extractBackground(&brush, &uri, &repeat, &alignment, &origin, &attachment, &clip))
-        bg = new QStyleSheetBackgroundData(brush, QPixmap(uri), repeat, alignment, origin, attachment, clip);
+    if (v.extractBackground(&brush, &uri, &repeat, &alignment, &origin, &attachment, &clip)) {
+        QPixmap pixmap(uri);
+        if (!uri.isEmpty() && pixmap.isNull())
+            qWarning("Could not create pixmap from %s", qPrintable(QDir::toNativeSeparators(uri)));
+        bg = new QStyleSheetBackgroundData(brush, pixmap, repeat, alignment, origin, attachment, clip);
+    }
 
     QBrush sfg, fg;
     QBrush sbg, abg;