[Development] Clarification needed on a crash caused by ignoring ownership of an object

[Andy Shaw]

Hi,

I am trying to determine what we should be doing inside Qt in a certain case. When a QUndoCommand is deleted after it has been given another QUndoCommand as a parent it will cause a crash since the parent has not been informed that the child was deleted. The documentation for QUndoCommand is explicit on the fact that when it has a parent the ownership of the QUndoCommand is transferred to its parent. As such I would not expect it to be possible to delete the child directly anymore as a result as we no longer own it. 

So the question is, since it is still a crash, should we still be accounting for this in the Qt code so as to prevent the crash or is it a case of it is documented to transfer ownership and as such we don’t want to protect against it being deleted out of Qt’s hands?

Andy