[PyQt] Segfault when trying to rely on QStyledItemDelegate.setEditorData/ModelData default behavior

[Elvis Stansvik]

Den 12 feb 2016 6:32 em skrev "Phil Thompson" <phil at riverbankcomputing.com>:
>
> On 12 Feb 2016, at 5:14 pm, Elvis Stansvik <elvstone at gmail.com> wrote:
> >
> > 2016-02-12 17:42 GMT+01:00 Phil Thompson <phil at riverbankcomputing.com>:
> >> On 12 Feb 2016, at 2:27 pm, Elvis Stansvik <elvstone at gmail.com> wrote:
> >>>
> >>> 2016-02-12 13:35 GMT+01:00 Phil Thompson <phil at riverbankcomputing.com
>:
> >>>> On 12 Feb 2016, at 12:31 pm, Elvis Stansvik <elvstone at gmail.com>
wrote:
> >>>>>
> >>>>> 2016-02-12 12:14 GMT+01:00 Phil Thompson <
phil at riverbankcomputing.com>:
> >>>>>> On 11 Feb 2016, at 8:53 pm, Elvis Stansvik <elvstone at gmail.com>
wrote:
> >>>>>>>
> >>>>>>> 2016-02-11 21:14 GMT+01:00 Elvis Stansvik <elvstone at gmail.com>:
> >>>>>>>> I found the problem, I had forgot to change the user property
from
> >>>>>>>> dict to QVariant (was testing around).
> >>>>>>>>
> >>>>>>>> With the property of type QVariant, it seems to work fine.
> >>>>>>>
> >>>>>>> I'm actually still interested in why I need to declare the Qt
property
> >>>>>>> as QVariant here. Why do I get a segfault if I declare it as dict?
> >>>>>>>
> >>>>>>> That is, in the paste
> >>>>>>> https://gist.github.com/estan/c051d1f798c4c46caa7d , why must it
be
> >>>>>>>
> >>>>>>> @pyqtProperty(QVariant, user=True)
> >>>>>>> def values(self):
> >>>>>>>     return self._values
> >>>>>>>
> >>>>>>> and not
> >>>>>>>
> >>>>>>> @pyqtProperty(dict, user=True)
> >>>>>>> def values(self):
> >>>>>>>     return self._values
> >>>>>>>
> >>>>>>> ?
> >>>>>>>
> >>>>>>> The value I store there (self._values) is a dict after all. Does
it
> >>>>>>> have something to do with the way in which
> >>>>>>> QStyledItemDelegate::setEditorData sets the property?
> >>>>>>
> >>>>>> Yes. It passes the address of a QVariant. PyQt uses the type of
the property to tell it what to do with the address.
> >>>>>
> >>>>> Aha, I think I understand: QStyledItemDelegate::setEditorData wraps
> >>>>> the value in a QVariant, and then crashes when trying to set the
> >>>>> property, because QVariant can't be converted to dict..?
> >>>>
> >>>> A QVariant can be converted to a dict (otherwise your code wouldn't
work at all) - but PyQt needs to know that it is a QVariant in the first
place.
> >>>
> >>> Hm, okay. But my goal was to keep this property as a dict, since
> >>> that's the data I'm storing, and not a QVariant. Why can't I declare
> >>> the property as a dict (since that's the data the editor is working
> >>> with), and then when QStyledItemDelegate::setEditorData sets the
> >>> property with a QVariant (which contains my dict), that QVariant is
> >>> automatically converted to a dict? (since that's what the property is
> >>> declared as).
> >>>
> >>> Sorry if I'm a little thick :/
> >>
> >> No, I am.
> >>
> >> Should be fixed in tonight's snapshot.
> >
> > Excellent! :) Since we're basing our product on Debian packaged PyQt,
> > I'll just live with having the "transport" QVariant property for now.
> >
> > Just out of curiosity, was this a fix of some general problem so to
> > speak, or was the fix to add some custom code (to the wrapping of
> > QStyledItemDelegate::setEditorData) that handles this particular case?
>
> It was a general problem.

Alright, even better that it got fixed then.

Elvis

>
> Phil
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