[PyQt] Unexpected segfault when using QSortFilterProxyModel with a QFileDialog

[Phil Thompson]

On Tue, 06 Oct 2009 18:18:32 -0500, Dave Peterson <dpeterson at enthought.com>
wrote:
> I must be doing something brain dead but I'm not sure what.   When I 
> display a QFileDialog after having set a proxy model, I get a seg fault 
> when the QFileDialog tries to save it's state.  Here's the top of the 
> stacktrace -- perhaps there is enough info here for someone else to be 
> able to tell where in the history() method something is going wrong?
> 
> Thread 0 Crashed:
> 0   QtGui                             0x02498e53 QFileDialog::history() 
> const + 115
> 1   QtGui                             0x02499115 
> QFileDialog::saveState() const + 229
> 2   QtGui                             0x024995f7 
> QFileDialog::~QFileDialog() + 231
> 3   QtGui.so                          0x01a4f137 
> sipQFileDialog::~sipQFileDialog() + 89
> 
> 
> And here's how I'm adding the proxy to the QFileDialog.
> 
>     dlg = QtGui.QFileDialog(parent, title, default_directory)
>     class MyFilterProxy(QtGui.QSortFilterProxyModel):
>         def filterAcceptsRow(self, source_row, source_parent):
>             logger.debug('MyFilterProxy: %s, %s' % (source_row, 
> source_parent))
>             return super(MyFilterProxy, 
> self).filterAcceptsRow(source_row, source_parent)
>     proxy = MyFilterProxy()
>     proxy.dynamicSortFilter = True  # filter whenever the source data 
> changes
>     dlg.setProxyModel(proxy)
> 
> 
> Is the problem that the QFileDialog is taking ownership of the proxy 
> instance and thus having memory fights with Python somehow?  Or does 
> PyQt properly handle that situation?   If not, what's the right way to 
> create a proxy instance so that this ownership over memory doesn't
happen?

It's a bug. The workaround will be to create the proxy model with a parent
(eg. the dialog).

Phil