Crash when using QListWidget::setItemWidget for the second time

[chenly]

This post is deleted!

[Christian Ehrlicher]

@chenly Then you did not look correctly in to Qt source code:

void QAbstractItemView::setIndexWidget(const QModelIndex &index, QWidget *widget)
{
    Q_D(QAbstractItemView);
    if (!d->isIndexValid(index))
        return;
    if (indexWidget(index) == widget)
        return;
    if (QWidget *oldWidget = indexWidget(index)) {
        d->persistent.remove(oldWidget);
        d->removeEditor(oldWidget);
        oldWidget->removeEventFilter(this);
        oldWidget->deleteLater(); <--- here
    }

See also https://doc.qt.io/qt-6/qabstractitemview.html#setIndexWidget

/edit: the QListWidget documentation was missing a note about the ownership: https://codereview.qt-project.org/c/qt/qtbase/+/588117

[Bonnie]

Because removeItemWidget will delete the widget.

[chenly]

@Bonnie "I thought the same way. So I changed searchBar to QPointer<QLineEdit>. QPointer will be set to nullptr when the object is deleted, but I checked searchBar after removeItemWidget(), and it wasn't nullptr. I also looked at the source code of removeItem(), and it actually just calls setItemWidget(item, nullptr), without performing any operations on itemWidget."

[Christian Ehrlicher]

@chenly Then you did not look correctly in to Qt source code:

void QAbstractItemView::setIndexWidget(const QModelIndex &index, QWidget *widget)
{
    Q_D(QAbstractItemView);
    if (!d->isIndexValid(index))
        return;
    if (indexWidget(index) == widget)
        return;
    if (QWidget *oldWidget = indexWidget(index)) {
        d->persistent.remove(oldWidget);
        d->removeEditor(oldWidget);
        oldWidget->removeEventFilter(this);
        oldWidget->deleteLater(); <--- here
    }

See also https://doc.qt.io/qt-6/qabstractitemview.html#setIndexWidget

/edit: the QListWidget documentation was missing a note about the ownership: https://codereview.qt-project.org/c/qt/qtbase/+/588117

[chenly]

@Christian-Ehrlicher thanks