Fix ancestor flags that are not correctly update when reparenting.

updateAncestorFlags was not reseting the flags if you change the parent
that have for instance itemsClipChildrenToShape to a new one that
doesn't have that flag.

Task-number:258956
Reviewed-by:bnilsen

2 files changed, 28 insertions, 11 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index aa37981..7b650d2 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -638,18 +638,19 @@ void QGraphicsItemPrivate::updateAncestorFlag(QGraphicsItem::GraphicsItemFlag ch
             return;
         }
 
-        // Inherit the enabled-state from our parents.
-        if ((parent && ((parent->d_ptr->ancestorFlags & flag)
-                        || (int(parent->d_ptr->flags & childFlag) == childFlag)
-                        || (childFlag == -1 && parent->d_ptr->handlesChildEvents)))) {
-            enabled = true;
-            ancestorFlags |= flag;
-        }
-
-        // Top-level root items don't have any ancestors, so there are no
-        // ancestor flags either.
-        if (!parent)
+        if (parent) {
+            // Inherit the enabled-state from our parents.
+            if ((parent->d_ptr->ancestorFlags & flag) || (int(parent->d_ptr->flags & childFlag) == childFlag) || (childFlag == -1 && parent->d_ptr->handlesChildEvents)) {
+                enabled = true;
+                ancestorFlags |= flag;
+            } else {
+                ancestorFlags &= ~flag;
+            }
+        } else {
+            // Top-level root items don't have any ancestors, so there are no
+            // ancestor flags either.
             ancestorFlags = 0;
+        }
     } else {
         // Don't set or propagate the ancestor flag if it's already correct.
         if (((ancestorFlags & flag) && enabled) || (!(ancestorFlags & flag) && !enabled))
diff --git a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
index 90c4636..ded8aca 100644
--- a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -665,6 +665,22 @@ void tst_QGraphicsItem::flags()
         QApplication::sendEvent(&scene, &event5);
         QCOMPARE(item->pos(), QPointF(10, 10));
     }
+    {
+        QGraphicsItem* clippingParent = new QGraphicsRectItem;
+        clippingParent->setFlag(QGraphicsItem::ItemClipsChildrenToShape, true);
+
+        QGraphicsItem* nonClippingParent = new QGraphicsRectItem;
+        nonClippingParent->setFlag(QGraphicsItem::ItemClipsChildrenToShape, false);
+
+        QGraphicsItem* child = new QGraphicsRectItem(nonClippingParent);
+        QVERIFY(!child->isClipped());
+
+        child->setParentItem(clippingParent);
+        QVERIFY(child->isClipped());
+
+        child->setParentItem(nonClippingParent);
+        QVERIFY(!child->isClipped());
+    }
 }
 
 void tst_QGraphicsItem::toolTip()