QGraphicsWidget update issues with ItemHasNoContents + effect

Items with the ItemHasNoContents flag set are never drawn so the
'paintedViewBoundingRect' is never cached/updated resulting in
updates wrongly being discarded. The solution is to always invalidate
the children for such items.

Auto test included.

Task-number: QT-3803

1 files changed, 29 insertions, 0 deletions

diff --git a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
index fa6a5ecbd7..e1bfb7985e 100644
--- a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
+++ b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
@@ -76,6 +76,7 @@ private slots:
     void dropShadowClipping();
     void childrenVisibilityShouldInvalidateCache();
     void prepareGeometryChangeInvalidateCache();
+    void itemHasNoContents();
 };
 
 void tst_QGraphicsEffect::initTestCase()
@@ -675,6 +676,34 @@ void tst_QGraphicsEffect::prepareGeometryChangeInvalidateCache()
     QCOMPARE(item->nbPaint, 0);
 }
 
+void tst_QGraphicsEffect::itemHasNoContents()
+{
+    QGraphicsRectItem *parent = new QGraphicsRectItem;
+    parent->setFlag(QGraphicsItem::ItemHasNoContents);
+
+    MyGraphicsItem *child = new MyGraphicsItem;
+    child->setParentItem(parent);
+    child->resize(200, 200);
+
+    QGraphicsScene scene;
+    scene.addItem(parent);
+
+    QGraphicsView view(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+    QTRY_COMPARE(child->nbPaint, 1);
+
+    CustomEffect *effect = new CustomEffect;
+    parent->setGraphicsEffect(effect);
+    QTRY_COMPARE(effect->numRepaints, 1);
+
+    for (int i = 0; i < 3; ++i) {
+        effect->reset();
+        effect->update();
+        QTRY_COMPARE(effect->numRepaints, 1);
+    }
+}
+
 QTEST_MAIN(tst_QGraphicsEffect)
 #include "tst_qgraphicseffect.moc"