Make sure PathView index isn't negative when filling the model

Pick-to: 6.5
Fixes: QTBUG-46487
Change-Id: Iba2a875756f0c06b86bb0a0aaf66eac329b2382b
Reviewed-by: Santhosh Kumar <[email protected]>
(cherry picked from commit b31bfde4bd840a94cdd4b2223e8f7c345850bd66)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>

3 files changed, 92 insertions, 0 deletions

diff --git a/src/quick/items/qquickpathview.cpp b/src/quick/items/qquickpathview.cpp
index 3b1f953208..ce61543f42 100644
--- a/src/quick/items/qquickpathview.cpp
+++ b/src/quick/items/qquickpathview.cpp
@@ -2025,6 +2025,7 @@ void QQuickPathView::refill()
                     startPos = d->highlightRangeStart;
                 // With no items, then "end" is just off the top so we populate via append
                 endIdx = (qRound(d->modelCount - d->offset) - 1) % d->modelCount;
+                endIdx = qMax(-1, endIdx); // endIdx shouldn't be smaller than -1
                 endPos = d->positionOfIndex(endIdx);
             }
             //Append
diff --git a/tests/auto/quick/qquickpathview/data/qtbug46487.qml b/tests/auto/quick/qquickpathview/data/qtbug46487.qml
new file mode 100644
index 0000000000..840d77ffe4
--- /dev/null
+++ b/tests/auto/quick/qquickpathview/data/qtbug46487.qml
@@ -0,0 +1,28 @@
+import QtQuick 2.0
+
+PathView {
+    id: view
+    property int delegatesCreated: 0
+    property int delegatesDestroyed: 0
+
+    width: 400
+    height: 400
+    preferredHighlightBegin: 0.5
+    preferredHighlightEnd: 0.5
+    pathItemCount: 5
+    currentIndex: 1
+    model: customModel
+    delegate: Text {
+        text: "item: " + index + " of: " + view.count
+        Component.onCompleted: view.delegatesCreated++;
+        Component.onDestruction: view.delegatesDestroyed++;
+    }
+    path: Path {
+        startX: 50
+        startY: 0
+        PathLine {
+            x: 50
+            y: 400
+        }
+    }
+}
diff --git a/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp b/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp
index e2edf87708..1b06e0047b 100644
--- a/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp
+++ b/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp
@@ -134,6 +134,7 @@ private slots:
     void mousePressAfterFlick();
     void qtbug90479();
     void overCached();
+    void qtbug46487();
 
 private:
     QScopedPointer<QPointingDevice> touchDevice = QScopedPointer<QPointingDevice>(QTest::createTouchDevice());
@@ -2935,6 +2936,68 @@ void tst_QQuickPathView::overCached()
     QVERIFY(pathview->property("delegatesDestroyed").toInt() <= 1);
 }
 
+class CustomModel : public QAbstractListModel
+{
+public:
+    CustomModel(QObject *parent = 0) : QAbstractListModel(parent) {
+        m_values << 0 << 1 << 2 << 3 << 4;
+    }
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const {
+        Q_UNUSED(parent);
+        return m_values.count();
+    }
+    QVariant data(const QModelIndex &index, int role) const {
+        if (index.row() < 0 || m_values.count() <= index.row())
+            return QVariant();
+
+        return m_values[index.row()];
+    }
+
+    Q_INVOKABLE void shrink() {
+        beginResetModel();
+        m_values.takeLast();
+        m_values.takeLast();
+        endResetModel();
+    }
+
+private:
+    QList<int> m_values;
+};
+
+void tst_QQuickPathView::qtbug46487()
+{
+    QScopedPointer<QQuickView> window(createView());
+
+    CustomModel* model = new CustomModel;
+    QQmlContext *ctxt = window->rootContext();
+    ctxt->setContextProperty("customModel", model);
+
+    window->setSource(testFileUrl("qtbug46487.qml"));
+    window->show();
+    qApp->processEvents();
+
+    QQuickPathView *pathview = qobject_cast<QQuickPathView*>(window->rootObject());
+    QVERIFY(pathview);
+
+    QTest::qWait(500);
+
+    // Should create just pathItemCount amount and not destroy any
+    QCOMPARE(pathview->count(), 5);
+    QCOMPARE(pathview->property("delegatesCreated").toInt(), 5);
+    QCOMPARE(pathview->property("delegatesDestroyed").toInt(), 0);
+
+    // Resets the model and removes 2 items.
+    model->shrink();
+    QTest::qWait(500);
+
+    // Should destroy previous items (begin/endResetModel) and
+    // (re)create 3 new items.
+    QCOMPARE(pathview->count(), 3);
+    QCOMPARE(pathview->property("delegatesCreated").toInt(), 5 + 3);
+    QCOMPARE(pathview->property("delegatesDestroyed").toInt(), 5);
+}
+
 QTEST_MAIN(tst_QQuickPathView)
 
 #include "tst_qquickpathview.moc"