[PyQt] pyqt5.1 baffling exceptions: AttributeError: 'Qxxxxxx' object has no attribute 'QWidget'

[Stephen Gava]

in case anyone searches this and needs workarounds for their code until 
the issue is resolved:

in the case of this error being triggered by using the result of 
QWidget.window() i worked around the error in all cases by explicitly 
passing a reference to the parent toplevel window all the way down the 
line to where i needed to reference it,

in the case of this error being triggered by using the result of 
QWidget.childAt() i had to implement separate logic to track and store a 
reference to the child widget the mouse cursor was over (which i did 
using mouse enter and leave events),

in both cases of course being able to use the reference to the toplevel 
or child obtained dynamically from .window() or .childAt() would have 
been much much simpler, and i'll revert my workarounds once we have a 
pyqt5 fix for this.

stephen.

On 05/10/13 18:19, Timothy W. Grove wrote:
> Hi Stephen,
>
> I don't really understand the issues here, but I also saw these kinds of
> errors cropping up recently when I moved an application from PyQt4 to
> PyQt5. I think I had at least three different cases of "AttributeError:
> 'Qxxxxxx' object has no attribute 'QWidget'". One case I fixed by not
> giving a parent to the instance I was creating, simply, 'instance =
> SomeWidgetClass(self, parent=None)'; another I fixed by actually giving
> it a parent (!), and for the third case I just had to write different
> code to accomplish my task.
>
> Sorry this isn't very specific but maybe it will give you something to
> try. I'm hoping its just a bug in PyQt5 which will sort itself out
> somewhere down the line ...
>
> Best regards,
> Tim
>
> On 05/10/2013 07:02, Stephen Gava wrote:
>> hi there,
>> i posted an earlier question about one specific instance of this
>> problem which seemed to relate to using QWidget.childAt() (no
>> replies), but now i have the same puzzling issue cropping up in
>> several places in a project i have moved from pyqt4 to pyqt5.
>>
>> under pyqt4 this code ran fine with none of these exceptions.
>>
>> under pyqt5 i'm getting exceptions of the kind detailed in the message
>> title from time to time, ie exceptions where the final error message is:
>>
>>  AttributeError: 'Qxxxxxx' object has no attribute 'QWidget'
>>
>> where Qxxxxxx is some kind of widget (in one instance QLabel, in
>> another couple of cases QMainWindow).
>>
>> these errors seem like they might be comming from pyqt5 itself, as i
>> don't reference QWidget as an attribute of any labels or mainwindows
>> in my own code, however the tracebacks i get only follow the stack in
>> my own code, in one instance this exception is thrown after a call to
>> QWidget.childAt() and in some other instances after calls to
>> QWidget.window()  (which was Qwidget.topLevelWidget() in pyqt4).
>>
>> as i said the pyqt4 version never throws these exceptions, and i can't
>> find anything in my code that should be causing this under pyqt5...
>>
>> does anyone have any advice on how i can at least try to work out
>> where the issue is coming from? it's definitely caused by something
>> new/different in ptqt5.
>>
>> thanks,
>> stephen.
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>
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