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>
 
 

3 files changed, 145 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickanimations/data/fastFlickingBug.qml b/tests/auto/quick/qquickanimations/data/fastFlickingBug.qml
new file mode 100644
index 0000000000..b2649a801b
--- /dev/null
+++ b/tests/auto/quick/qquickanimations/data/fastFlickingBug.qml
@@ -0,0 +1,114 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+import QtQuick 2.11
+import QtQuick.Window 2.11
+
+Window {
+    id: root
+    property alias timer : timer
+    property alias listView : listView
+    property alias theModel: theModel
+    property variant ops: [{'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39},
+    {'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39},
+    {'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39},
+    {'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39},
+    {'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39},
+    {'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39},
+    {'op': 'add', 'count': 30}, {'op': 'add', 'count': 60}, {'op': 'rem', 'count': 40}, {'op': 'rem', 'count': 10}, {'op': 'rem', 'count': 39}]
+    property int opIndex : 0
+    width: 400
+    height: 600
+
+    ListModel {
+        id: theModel
+    }
+
+    Timer {
+        id: timer
+        interval: 100
+        running: false
+        repeat: true
+        onTriggered: {
+            if (opIndex >= ops.length) {
+                timer.stop()
+                return
+            }
+            let op = ops[opIndex]
+            for (var i = 0; i < op.count; ++i) {
+                if (op.op === "add")
+                    theModel.append({"name": "opIndex " + opIndex})
+                else
+                    theModel.remove(0, 1);
+            }
+            opIndex = opIndex + 1
+        }
+    }
+
+    ListView {
+        id: listView
+        anchors.fill: parent
+        spacing: 4
+        model: theModel
+        header: Text {
+            text: "YAnimator"
+        }
+        add: Transition {
+            NumberAnimation { property: "scale";   from: 0; to: 1; duration: 200 }
+            NumberAnimation { property: "opacity"; from: 0; to: 1; duration: 200 }
+        }
+        displaced: Transition {
+            YAnimator { duration: 500 }
+            NumberAnimation { property: "opacity"; to: 1.0; duration: 1000 }
+            NumberAnimation { property: "scale";   to: 1.0; duration: 1000 }
+        }
+        remove: Transition {
+            NumberAnimation { property: "opacity"; to: 0; duration: 200 }
+            NumberAnimation { property: "scale";   to: 0; duration: 200 }
+        }
+        delegate: Rectangle {
+            width: 200
+            height: 20
+            color:"red"
+            Text {
+                anchors.centerIn: parent
+                text: name
+            }
+        }
+    }
+}
diff --git a/tests/auto/quick/qquickanimations/qquickanimations.pro b/tests/auto/quick/qquickanimations/qquickanimations.pro
index cf9c87a305..1c5494a24a 100644
--- a/tests/auto/quick/qquickanimations/qquickanimations.pro
+++ b/tests/auto/quick/qquickanimations/qquickanimations.pro
@@ -27,6 +27,7 @@ OTHER_FILES += \
     data/dotproperty.qml \
     data/Double.qml \
     data/doubleRegistrationBug.qml \
+    data/fastFlickingBug.qml \
     data/looping.qml \
     data/mixedtype1.qml \
     data/mixedtype2.qml \
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"