Prevent badly formed texture nodes in the scene graph.

A texture based node without a valid texture is not allowed,
as the material and the renderer will only tolerate
well-formed nodes. If a node is missing any part of its material
state it should not be in the scene graph in the first place.

Because of an "optimization" in QSGDefaultImageNode::setTexture
and QSGSimpleTextureNode::setTexture, we must temporarily set
the texture to 0 to ensure that it gets updated properly. This
temporarily puts the node into an invalid state which can lead
to crashes when QSGNode::markDirty() reaches the renderer.

Task-number: QTBUG-34062
Change-Id: Ic1735c9b974b90b3684262de9589133c961bac6e
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/src/quick/items/qquickborderimage.cpp b/src/quick/items/qquickborderimage.cpp
index 3cbcf1937f..9fc9752707 100644
--- a/src/quick/items/qquickborderimage.cpp
+++ b/src/quick/items/qquickborderimage.cpp
@@ -560,10 +560,14 @@ QSGNode *QQuickBorderImage::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeDat
 
     QSGImageNode *node = static_cast<QSGImageNode *>(oldNode);
 
-    if (!node)
+    bool updatePixmap = d->pixmapChanged;
+    if (!node) {
         node = d->sceneGraphContext()->createImageNode();
+        updatePixmap = true;
+    }
 
-    node->setTexture(texture);
+    if (updatePixmap)
+        node->setTexture(texture);
 
     // Don't implicitly create the scalegrid in the rendering thread...
     QRectF innerSourceRect(0, 0, 1, 1);