Instantiator: don't interfere with delegates that assign parents

[ChangeLog][QtQml][Instantiator] Instantiator now avoids re-assigning a
delegate object's parent to itself if it was already set; thus, you can
now declare a parent assignment.

Task-number: QTBUG-64546
Task-number: QTBUG-84730
Change-Id: I7d95fa76e71c363b4cb5b7a512c2e984488c8af4
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

4 files changed, 33 insertions, 8 deletions

diff --git a/examples/quick/pointerhandlers/pointerhandlers.qml b/examples/quick/pointerhandlers/pointerhandlers.qml
index a5cbbbd56a..db33b961cb 100644
--- a/examples/quick/pointerhandlers/pointerhandlers.qml
+++ b/examples/quick/pointerhandlers/pointerhandlers.qml
@@ -83,13 +83,10 @@ Rectangle {
         z: 10000
         anchors.fill: parent
 
-        // TODO use Instantiator to create these... but we need to be able to set their parents to glassPane somehow (QTBUG-64546)
-        TouchpointFeedbackSprite { }
-        TouchpointFeedbackSprite { }
-        TouchpointFeedbackSprite { }
-        TouchpointFeedbackSprite { }
-        TouchpointFeedbackSprite { }
-        TouchpointFeedbackSprite { }
+        Instantiator {
+            model: 10
+            delegate: TouchpointFeedbackSprite { parent: glassPane }
+        }
 
         MouseFeedbackSprite { }
     }
diff --git a/src/qmlmodels/qqmlinstantiator.cpp b/src/qmlmodels/qqmlinstantiator.cpp
index cb7ca1126c..d7b70d20d6 100644
--- a/src/qmlmodels/qqmlinstantiator.cpp
+++ b/src/qmlmodels/qqmlinstantiator.cpp
@@ -128,7 +128,8 @@ void QQmlInstantiatorPrivate::_q_createdItem(int idx, QObject* item)
         return;
     if (requestedIndex != idx) // Asynchronous creation, reference the object
         (void)instanceModel->object(idx);
-    item->setParent(q);
+    if (!item->parent())
+        item->setParent(q);
     if (objects.size() < idx + 1) {
         int modelCount = instanceModel->count();
         if (objects.capacity() < modelCount)
diff --git a/tests/auto/qml/qqmlinstantiator/data/handlerWithParent.qml b/tests/auto/qml/qqmlinstantiator/data/handlerWithParent.qml
new file mode 100644
index 0000000000..a032b19efc
--- /dev/null
+++ b/tests/auto/qml/qqmlinstantiator/data/handlerWithParent.qml
@@ -0,0 +1,12 @@
+import QtQuick
+
+Item {
+    id: root
+    Instantiator {
+        model: 2
+        delegate: PointHandler {
+            objectName: "pointHandler"
+            parent: root
+        }
+    }
+}
diff --git a/tests/auto/qml/qqmlinstantiator/tst_qqmlinstantiator.cpp b/tests/auto/qml/qqmlinstantiator/tst_qqmlinstantiator.cpp
index 4c6c84a9d2..a0ab2cda5b 100644
--- a/tests/auto/qml/qqmlinstantiator/tst_qqmlinstantiator.cpp
+++ b/tests/auto/qml/qqmlinstantiator/tst_qqmlinstantiator.cpp
@@ -56,6 +56,8 @@ private slots:
 
     void asynchronous_data();
     void asynchronous();
+
+    void handlerWithParent();
 };
 
 tst_qqmlinstantiator::tst_qqmlinstantiator()
@@ -276,6 +278,19 @@ void tst_qqmlinstantiator::asynchronous()
     }
 }
 
+void tst_qqmlinstantiator::handlerWithParent()
+{
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("handlerWithParent.qml"));
+    QObject *rootObject = component.create();
+    QVERIFY(rootObject != nullptr);
+    const auto handlers = rootObject->findChildren<QObject *>("pointHandler");
+    QCOMPARE(handlers.count(), 2);
+    for (const auto *h : handlers) {
+        QCOMPARE(h->parent(), rootObject);
+    }
+}
+
 QTEST_MAIN(tst_qqmlinstantiator)
 
 #include "tst_qqmlinstantiator.moc"