Gentle ping as I got no answers before. ----------------------------------------------------------------------------
Hi everyone, While trying to submit a patch to fix QStringListModel::setItemData https://codereview.qt-project.org/235730 we opened a much larger discussion on QAbstractItemModel, that expanded on the forum https://forum.qt.io/topic/93207/qabstractitemmodel-setitemdata-partial-success but that I ultimately would like your opinion on: At the moment, QAbstractItemModel::setItemData calls setData for each role until the first failure and returns false if that happens. This opens up 2 issues: * QAbstractItemModel::setItemData returns false even when some but not all data was actually set without rolling back the changes * QAbstractItemModel::setItemData depends on the ordering of the roles For the second point, an example that illustrates the problem is (QStringListModel::setItemData just uses the base class implementation): QStringListModel::setItemData({{Qt::DisplayRole,QVariant("test")},{ Qt::DecorationRole,QVariant(QIcon())}) will return false but actually set the string to "test" QStringListModel::setItemData({{Qt::EditRole,QVariant("test")},{ Qt::DecorationRole,QVariant(QIcon())}) will return false and do nothing on the model My proposal is: * Remove the ordering-dependency QAbstractItemModel::setItemData (i.e. sets all the roles it can and returns false if any of them failed) * Make setItemData in subclasses of QAbstractItemModel behave transaction-like (i.e. try to set all the roles, if any fails rollback the other changes and return false) This however is technically a change of behaviour so I would like people way smarter than me to agree on the way forward. Thanks, Regards, Luca Beldi (aka VRonin)
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