If no screens, attempting to create a window results in clean exit

Asserting is only relevant for debug builds, and there were a couple
of other places that a segfault would typically occur before the assert
had a chance.

Change-Id: I1abc82eb3ecfa91050117fab1525f4cbd82ff486
Task-number: QTBUG-37876
Reviewed-by: Andy Shaw <andy.shaw@digia.com>
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/widgets/util/qcolormap.cpp b/src/widgets/util/qcolormap.cpp
index 03ee8a395e..decfd7bd2c 100644
--- a/src/widgets/util/qcolormap.cpp
+++ b/src/widgets/util/qcolormap.cpp
@@ -66,7 +66,12 @@ static QColormapPrivate *screenMap = 0;
 void QColormap::initialize()
 {
     screenMap = new QColormapPrivate;
-
+    if (!QGuiApplication::primaryScreen()) {
+        qWarning("no screens available, assuming 24-bit color");
+        screenMap->depth = 24;
+        screenMap->mode = QColormap::Direct;
+        return;
+    }
     screenMap->depth = QGuiApplication::primaryScreen()->depth();
     if (screenMap->depth < 8) {
         screenMap->mode = QColormap::Indexed;