QQuickItemView: fix crash while doing fast flicking in transitions

The cause was that fast flicking kicked items in and out of viewport,
while in transition, they would abruptly having tracking data structure
, i.e. releasePendingTransition of QQuickItemViewPrivate, got iterator
invalidated. This also helps to resolve QTBUG-44308.

Fixes: QTBUG-76433
Fixes: QTBUG-44308
Change-Id: If14533d3f6b1acd7b6ca0c5c723347c0cb3f54dc
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>
 
 

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickanimations/tst_qquickanimations.cpp b/tests/auto/quick/qquickanimations/tst_qquickanimations.cpp
index 1dad0c771c..d9b42bdeb5 100644
--- a/tests/auto/quick/qquickanimations/tst_qquickanimations.cpp
+++ b/tests/auto/quick/qquickanimations/tst_qquickanimations.cpp
@@ -40,6 +40,7 @@
 #include <QtQuick/private/qquickanimatorjob_p.h>
 #include <QtQuick/private/qquickpathinterpolator_p.h>
 #include <QtQuick/private/qquickitem_p.h>
+#include <QtQuick/private/qquicklistview_p.h>
 #include <QEasingCurve>
 
 #include <limits.h>
@@ -110,6 +111,7 @@ private slots:
     void finished();
     void replacingTransitions();
     void animationJobSelfDestruction();
+    void fastFlickingBug();
 };
 
 #define QTIMED_COMPARE(lhs, rhs) do { \
@@ -1744,6 +1746,34 @@ void tst_qquickanimations::animationJobSelfDestruction()
     QTest::qWait(1000);
 }
 
+void tst_qquickanimations::fastFlickingBug()
+{
+    // Don't crash
+    QQmlEngine engine;
+    engine.clearComponentCache();
+    QQmlComponent c(&engine, testFileUrl("fastFlickingBug.qml"));
+    QScopedPointer<QQuickWindow> win(qobject_cast<QQuickWindow*>(c.create()));
+    if (!c.errors().isEmpty())
+        qDebug() << c.errorString();
+    QVERIFY(win);
+    win->setTitle(QTest::currentTestFunction());
+    win->show();
+    QVERIFY(QTest::qWaitForWindowExposed(win.data()));
+    auto timer = win->property("timer").value<QQmlTimer*>();
+    QVERIFY(timer);
+    QCOMPARE(timer->isRunning(), false);
+    auto listView = win->property("listView").value<QQuickFlickable*>();
+    QVERIFY(listView);
+    timer->start();
+    // flick listView up and down quickly in the middle of a slow transition
+    for (int sign = 1; timer->isRunning(); sign *= -1) {
+        listView->flick(0, sign * 4000);
+        qApp->processEvents();
+        QTest::qWait(53);
+        qApp->processEvents();
+    }
+}
+
 QTEST_MAIN(tst_qquickanimations)
 
 #include "tst_qquickanimations.moc"