[PyQt] Problems with QQmlListProperty and Qml object ownership

[Phil Thompson]

On Tue, 29 Oct 2013 01:23:12 +0100, Juan Pedro Bolívar Puente
<raskolnikov at gnu.org> wrote:
> Hi!
> 
> I am using PyQt5 and while I love the approach I have found a couple of 
> serious issues, the latter one becoming a real showstopper.  I have 
> tried both with Qt 5.1 and 5.2.
> 
> 1. Objects are not kept alive by Qml, meaning the application soon 
> crashes if I do not keep the references alive.  I am now keeping all my 
> objects alive, but sadly this means I have some memory leaks now.  Is 
> there a way to fix it?  I was considering moving parts of the 
> application to C++ in the future: can this problem be solved in C++ or 
> is it an inherent limitation of Qml memory model?

I would have expected QML to either pass a parent or to document that it
will take ownership of the created QObject. However it doesn't so you need
to keep a reference (or give it a parent) yourself. However I don't see how
you would then get memory leaks.

> 2. I am having very weird crashes with QQmlListProperty. First, my usage

> of QQmlListProperty looks a bit like this (not exactly, but you get the 
> idea):

You need to provide a complete, self contained example that demonstrates
the problem.

Phil