Update roleNames in QAbstractProxyModel if sourceModel resets.

If a sourceModel resets, it's roleNames might have changed. This
is most likely the case if sourceModel itself is also a proxy model
of which the sourceModel was changed.

Task-number: QTBUG-28982
Change-Id: I102788f2c9bf97b4002b350673f9219e32e7a052
Reviewed-by: Nils Jeisecke <jeisecke@saltation.de>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>

src/corelib/itemmodels/qabstractproxymodel.cpp

@@ -147,6 +147,15 @@ void QAbstractProxyModel::setSourceModel(QAbstractItemModel *sourceModel)
     }
 }
 
+/*!
+    Clears the roleNames of this proxy model.
+*/
+void QAbstractProxyModel::resetInternalData()
+{
+    Q_D(QAbstractProxyModel);
+    d->roleNames = d->model->roleNames();
+}
+
 /*!
     Returns the model that contains the data that is available through the proxy model.
 */

src/corelib/itemmodels/qabstractproxymodel.h

@@ -101,6 +101,9 @@ Q_SIGNALS:
 #endif
     );
 
+protected Q_SLOTS:
+    void resetInternalData();
+
 protected:
     QAbstractProxyModel(QAbstractProxyModelPrivate &, QObject *parent);
 

tests/auto/corelib/itemmodels/qsortfilterproxymodel/tst_qsortfilterproxymodel.cpp

@@ -146,6 +146,8 @@ private slots:
     void hierarchyFilterInvalidation();
     void simpleFilterInvalidation();
 
+    void chainedProxyModelRoleNames();
+
 protected:
     void buildHierarchy(const QStringList &data, QAbstractItemModel *model);
     void checkHierarchy(const QStringList &data, const QAbstractItemModel *model);
@@ -3767,6 +3769,45 @@ void tst_QSortFilterProxyModel::simpleFilterInvalidation()
     model.insertRow(0, new QStandardItem("extra"));
 }
 
+class CustomRoleNameModel : public QAbstractListModel
+{
+    Q_OBJECT
+public:
+    CustomRoleNameModel(QObject *parent = 0) : QAbstractListModel(parent) {}
+
+    QVariant data(const QModelIndex &index, int role) const
+    {
+        Q_UNUSED(index);
+        Q_UNUSED(role);
+        return QVariant();
+    }
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const
+    {
+        Q_UNUSED(parent);
+        return 0;
+    }
+
+    QHash<int, QByteArray> roleNames() const
+    {
+        QHash<int, QByteArray> rn = QAbstractListModel::roleNames();
+        rn[Qt::UserRole + 1] = "custom";
+        return rn;
+    }
+};
+
+void tst_QSortFilterProxyModel::chainedProxyModelRoleNames()
+{
+    QSortFilterProxyModel proxy1;
+    QSortFilterProxyModel proxy2;
+    CustomRoleNameModel customModel;
+
+    proxy2.setSourceModel(&proxy1);
+
+    // changing the sourceModel of proxy1 must also update roleNames of proxy2
+    proxy1.setSourceModel(&customModel);
+    QVERIFY(proxy2.roleNames().value(Qt::UserRole + 1) == "custom");
+}
 
 QTEST_MAIN(tst_QSortFilterProxyModel)
 #include "tst_qsortfilterproxymodel.moc"