Destroy an incubating delegate if it is removed before incubation completes

Removing an item from a model after its delegate has started incubation,
but before it has completed results is an orphaned item.

Task-number: QTBUG-55901
Change-Id: I3d3136dc05a950ca38d53687ae7d38a6d0c7ec35
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>

2 files changed, 21 insertions, 6 deletions

diff --git a/src/qml/types/qqmldelegatemodel.cpp b/src/qml/types/qqmldelegatemodel.cpp
index f2de911725..21f89cd4ec 100644
--- a/src/qml/types/qqmldelegatemodel.cpp
+++ b/src/qml/types/qqmldelegatemodel.cpp
@@ -1310,9 +1310,23 @@ void QQmlDelegateModelPrivate::itemsRemoved(
                     }
                 } else {
                     if (QQDMIncubationTask *incubationTask = cacheItem->incubationTask) {
-                        for (int i = 1; i < m_groupCount; ++i) {
-                            if (remove.inGroup(i))
-                                incubationTask->index[i] = remove.index[i];
+                        if (!cacheItem->isObjectReferenced()) {
+                            releaseIncubator(cacheItem->incubationTask);
+                            cacheItem->incubationTask = 0;
+                            if (cacheItem->object) {
+                                QObject *object = cacheItem->object;
+                                cacheItem->destroyObject();
+                                if (QQuickPackage *package = qmlobject_cast<QQuickPackage *>(object))
+                                    emitDestroyingPackage(package);
+                                else
+                                    emitDestroyingItem(object);
+                            }
+                            cacheItem->scriptRef -= 1;
+                        } else {
+                            for (int i = 1; i < m_groupCount; ++i) {
+                                if (remove.inGroup(i))
+                                    incubationTask->index[i] = remove.index[i];
+                            }
                         }
                     }
                     if (QQmlDelegateModelAttached *attached = cacheItem->attached) {
diff --git a/tests/auto/quick/qquickvisualdatamodel/tst_qquickvisualdatamodel.cpp b/tests/auto/quick/qquickvisualdatamodel/tst_qquickvisualdatamodel.cpp
index d578a0900c..dc8b35d3e8 100644
--- a/tests/auto/quick/qquickvisualdatamodel/tst_qquickvisualdatamodel.cpp
+++ b/tests/auto/quick/qquickvisualdatamodel/tst_qquickvisualdatamodel.cpp
@@ -4093,9 +4093,10 @@ void tst_qquickvisualdatamodel::asynchronousRemove()
             controller.incubateFor(50);
         } while (timer.elapsed() < 1000 && controller.incubatingObjectCount() > 0);
 
-        QVERIFY(requester.itemInitialized);
-        QCOMPARE(requester.itemCreated, requester.itemInitialized);
-        QCOMPARE(requester.itemDestroyed, requester.itemInitialized);
+        // The item was removed before incubation started. We should not have any item created.
+        QVERIFY(!requester.itemInitialized);
+        QVERIFY(!requester.itemCreated);
+        QVERIFY(!requester.itemDestroyed);
     } else {
         item = qobject_cast<QQuickItem*>(visualModel->object(completeIndex, false));
         QVERIFY(item);