From e7a10b00be3e4aa197900ecf424e6d44b07248ae Mon Sep 17 00:00:00 2001
From: J-P Nurmi <jpnurmi@gmail.com>
Date: Tue, 20 Oct 2009 18:03:10 +0300
Subject: Fixed QGraphicsScene::clear() not to crash if related top level items
 happen to delete each others.

Merge-Request: 1863
Reviewed-by: Andreas
Reviewed-by: Olivier
---
 src/gui/graphicsview/qgraphicsscene.cpp          |  5 +++--
 tests/auto/qgraphicsscene/tst_qgraphicsscene.cpp | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index a62e486..a4965e4 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -2292,8 +2292,9 @@ void QGraphicsScene::clear()
     // NB! We have to clear the index before deleting items; otherwise the
     // index might try to access dangling item pointers.
     d->index->clear();
-    const QList<QGraphicsItem *> items = d->topLevelItems;
-    qDeleteAll(items);
+    // NB! QGraphicsScenePrivate::unregisterTopLevelItem() removes items
+    while (!d->topLevelItems.isEmpty())
+        delete d->topLevelItems.first();
     Q_ASSERT(d->topLevelItems.isEmpty());
     d->lastItemCount = 0;
     d->allItemsIgnoreHoverEvents = true;
diff --git a/tests/auto/qgraphicsscene/tst_qgraphicsscene.cpp b/tests/auto/qgraphicsscene/tst_qgraphicsscene.cpp
index 0589994..4f76ddd 100644
--- a/tests/auto/qgraphicsscene/tst_qgraphicsscene.cpp
+++ b/tests/auto/qgraphicsscene/tst_qgraphicsscene.cpp
@@ -1453,6 +1453,13 @@ void tst_QGraphicsScene::focusItemLostFocus()
     item->clearFocus();
 }
 
+class ClearTestItem : public QGraphicsRectItem
+{
+public:
+    ~ClearTestItem() { qDeleteAll(items); }
+    QList<QGraphicsItem *> items;
+};
+
 void tst_QGraphicsScene::clear()
 {
     QGraphicsScene scene;
@@ -1463,6 +1470,19 @@ void tst_QGraphicsScene::clear()
     scene.clear();
     QVERIFY(scene.items().isEmpty());
     QCOMPARE(scene.sceneRect(), QRectF(0, 0, 100, 100));
+
+    ClearTestItem *firstItem = new ClearTestItem;
+    QGraphicsItem *secondItem = new QGraphicsRectItem;
+    firstItem->items += secondItem;
+
+    scene.setItemIndexMethod(QGraphicsScene::NoIndex);
+    scene.addItem(firstItem);
+    scene.addItem(secondItem);
+    QCOMPARE(scene.items().at(0), firstItem);
+    QCOMPARE(scene.items().at(1), secondItem);
+    // must not crash even if firstItem deletes secondItem
+    scene.clear();
+    QVERIFY(scene.items().isEmpty());
 }
 
 void tst_QGraphicsScene::setFocusItem()
-- 
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