Models: Avoid crashes when deleting cache items

Pick-to: 6.5 6.2 5.15
Fixes: QTBUG-91425
Change-Id: I58cf9ee29922f83fc6621f771b80ed557b31f106
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

2 files changed, 62 insertions, 0 deletions

diff --git a/tests/auto/qml/qqmldelegatemodel/data/deleteRace.qml b/tests/auto/qml/qqmldelegatemodel/data/deleteRace.qml
new file mode 100644
index 0000000000..b01b14f7b8
--- /dev/null
+++ b/tests/auto/qml/qqmldelegatemodel/data/deleteRace.qml
@@ -0,0 +1,50 @@
+import QtQuick
+import QtQml.Models
+
+Item {
+    DelegateModel {
+        id: delegateModel
+        model: ListModel {
+            id: sourceModel
+
+            ListElement { title: "foo" }
+            ListElement { title: "bar" }
+
+            function clear() {
+                if (count > 0)
+                    remove(0, count);
+            }
+        }
+
+        groups: [
+            DelegateModelGroup { name: "selectedItems" }
+        ]
+
+        delegate: Text {
+            height: DelegateModel.inSelectedItems ? implicitHeight * 2 : implicitHeight
+            Component.onCompleted: {
+                if (index === 0)
+                    DelegateModel.inSelectedItems = true;
+            }
+        }
+
+        Component.onCompleted: {
+            items.create(0)
+            items.create(1)
+        }
+    }
+
+    ListView {
+        anchors.fill: parent
+        model: delegateModel
+    }
+
+    Timer {
+        running: true
+        interval: 10
+        onTriggered: sourceModel.clear()
+    }
+
+    property int count: delegateModel.items.count
+}
+
diff --git a/tests/auto/qml/qqmldelegatemodel/tst_qqmldelegatemodel.cpp b/tests/auto/qml/qqmldelegatemodel/tst_qqmldelegatemodel.cpp
index 2ccd7a7111..fe67f703b9 100644
--- a/tests/auto/qml/qqmldelegatemodel/tst_qqmldelegatemodel.cpp
+++ b/tests/auto/qml/qqmldelegatemodel/tst_qqmldelegatemodel.cpp
@@ -29,6 +29,7 @@ private slots:
     void redrawUponColumnChange();
     void nestedDelegates();
     void universalModelData();
+    void deleteRace();
 };
 
 class AbstractItemModel : public QAbstractItemModel
@@ -359,6 +360,17 @@ void tst_QQmlDelegateModel::universalModelData()
 
 }
 
+void tst_QQmlDelegateModel::deleteRace()
+{
+    QQmlEngine engine;
+    QQmlComponent c(&engine, testFileUrl("deleteRace.qml"));
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(!o.isNull());
+    QTRY_COMPARE(o->property("count").toInt(), 2);
+    QTRY_COMPARE(o->property("count").toInt(), 0);
+}
+
 QTEST_MAIN(tst_QQmlDelegateModel)
 
 #include "tst_qqmldelegatemodel.moc"