Invert QTreeWidgetItem clear function loop

When using clear on an item with children,
we rely on the childCount() function so when children
with only a parent and no local reference were inside,
they ended up being removed, altering the behavior of the loop.

Change-Id: I111a600cd2e805eeb7110082437e666f88ff65a5
Fixes: PYSIDE-1251
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 9 insertions, 1 deletions

diff --git a/sources/pyside2/PySide2/glue/qtwidgets.cpp b/sources/pyside2/PySide2/glue/qtwidgets.cpp
index 1c663364c..4f9baadf1 100644
--- a/sources/pyside2/PySide2/glue/qtwidgets.cpp
+++ b/sources/pyside2/PySide2/glue/qtwidgets.cpp
@@ -413,7 +413,15 @@ for (auto *item : items) {
 // @snippet qtreewidget-clear
 QTreeWidgetItem *rootItem = %CPPSELF.invisibleRootItem();
 Shiboken::BindingManager &bm = Shiboken::BindingManager::instance();
-for (int i = 0, i_count = rootItem->childCount(); i < i_count; ++i) {
+
+// PYSIDE-1251:
+// Since some objects can be created with a parent and without
+// being saved on a local variable (refcount = 1), they will be
+// deleted when setting the parent to nullptr, so we change the loop
+// to do this from the last child to the first, to avoid the case
+// when the child(1) points to the original child(2) in case the
+// first one was removed.
+for (int i = rootItem->childCount() - 1; i >= 0; --i) {
     QTreeWidgetItem *item = rootItem->child(i);
     if (SbkObject *wrapper = bm.retrieveWrapper(item))
         Shiboken::Object::setParent(nullptr, reinterpret_cast<PyObject *>(wrapper));