Allow proxy models access to the parent-child hierarchy of source

As discussed in the related bug report, the current way proxy models
access the parent-child hierarchy of the source model requires modifying
Qt sources. This changes adds a method to allow easy implementation
of this common feature to proxy model subclasses.

Fixes: QTBUG-83911
Change-Id: Ic88d40c13c2be7b6b44fcc58118bac471a11da95
Reviewed-by: David Faure <david.faure@kdab.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/src/corelib/itemmodels/qabstractitemmodel.h b/src/corelib/itemmodels/qabstractitemmodel.h
index 789ed60ce4..0b61275d23 100644
--- a/src/corelib/itemmodels/qabstractitemmodel.h
+++ b/src/corelib/itemmodels/qabstractitemmodel.h
@@ -272,8 +272,7 @@ class Q_CORE_EXPORT QAbstractItemModel : public QObject
 
     friend class QPersistentModelIndexData;
     friend class QAbstractItemViewPrivate;
-    friend class QIdentityProxyModel;
-    friend class QTransposeProxyModelPrivate;
+    friend class QAbstractProxyModel;
 public:
 
     explicit QAbstractItemModel(QObject *parent = nullptr);