[PySide] Bug is worse (was: QObject.destroyed() is not emitted)
tismer at stackless.com
Thu Nov 29 23:40:11 CET 2012
On 11/29/12 6:37 PM, Stephan Deibel wrote:
> Alexey Vihorev wrote:
>> Thanks, nice find, but... I hit the next hurdle trying to go this
>> way. The signal QObject.destroyed(obj) is passing no arguments
>> (probably because obj is already destroyed), so my static method has
>> nothing to work on. Which kind of devaluates the whole idea, IMHO.
>> And in PyQt4 it*does* pass the object. Even more: in PyQt4 there is
>> no need for static method approach, as it works perfectly with
>> instance methods:
> Yea, you would have to bind the necessary data to the callback like this:
> def on_destroy(val1=self.whatever, val2=self.something):
> print 'destroyed'
> Whether this is possible or useful in your case is of course going to
> depend on the details of the code.
> Having 'destroyed' be emitted before the object is destroyed and
> getting the object reference as an arg makes more sense to me. That is
> what PyQt seems to do and it is what QObject does under Qt using C++,
> so I'd call this a bug in PySide. I've added
This bug is only half of the story:
We had that simple @staticmethod work-around.
But actually, the main reason seems to be that PySide suffers
any reference cycle.
The tiny example again breaks as soon as I add a property:
from PySide.QtCore import QAbstractTableModel, QObject
def __init__(self, *args):
m = MyModel()
Remove the @property, and it works, again.
Rule of thumb:
If you need anything like a property, use a normal Python class
and put your Qt object into it as an attribute. Otherwise your
program will tend to grow in memory ;-)
Stefan, I added this code to your bug report.
cheers - chris
Christian Tismer :^) <mailto:tismer at stackless.com>
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