QQuickItemView: Don't change the viewport while in layout

Moving the viewport in the middle of a layout operation is a bad idea as
it causes the visible items to change.

Task-number: QTBUG-49224
Change-Id: I45a214560e00b65ed53b9385e7a539bb4304b7d9
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 17 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
index 1ca341fe66..a9be9d4fa4 100644
--- a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
+++ b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
@@ -270,6 +270,7 @@ private slots:
     void useDelegateChooserWithoutDefault();
 
     void addOnCompleted();
+    void setPositionOnLayout();
 
 private:
     template <class T> void items(const QUrl &source);
@@ -8860,6 +8861,22 @@ void tst_QQuickListView::addOnCompleted()
     }
 }
 
+void tst_QQuickListView::setPositionOnLayout()
+{
+    // Make sure we don't trigger a crash by removing items during layout from setPosition().
+    QScopedPointer<QQuickView> window(createView());
+    window->setSource(testFileUrl("setpositiononlayout.qml"));
+    window->show();
+    QVERIFY(QTest::qWaitForWindowExposed(window.data()));
+    window->requestActivate();
+    QVERIFY(QTest::qWaitForWindowActive(window.data()));
+    for (int i = 0; i < 1000; ++i) {
+        QTest::keyPress(window.data(), Qt::Key_Down);
+        QTest::qWait(1);
+        QTest::keyRelease(window.data(), Qt::Key_Down);
+    }
+}
+
 void tst_QQuickListView::useDelegateChooserWithoutDefault()
 {
     // Check that the application doesn't crash