Bug 413 – Base class not correctly detected for a class derived from QtGui.QWidget

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Bug 413 - Base class not correctly detected for a class derived from QtGui.QWidget

Summary:

Base class not correctly detected for a class derived from QtGui.QWidget

Status:	CLOSED WONTFIX

Product:	PySide
Classification:	Unclassified
Component:	PySide
Version:	0.4.2
Platform:	All All

Importance:	P3 normal
Assigned To:	renato filho

URL:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2010-10-14 10:06 EEST by Matti Airas
Modified:	2010-11-25 17:53 EET (History)
CC List:	8 users (show)

See Also:

Attachments
The complete failing example (20.52 KB, application/x-bzip) 2010-10-14 10:06 EEST, Matti Airas	Details
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Description Matti Airas 2010-10-14 10:06:21 EEST

Created attachment 116 [details]
The complete failing example

When porting PyQt's anomation/easing example, I get following:

Traceback (most recent call last):
  File "./easing.py", line 216, in <module>
    w = Window()
  File "./easing.py", line 71, in __init__
    super(QtGui.QWidget, self).__init__(parent)
TypeError: PySide.QtCore.QObject isn't a direct base class of Window

even though the code clearly states:

class Window(QtGui.QWidget):
    def __init__(self, parent=None):
        super(QtGui.QWidget, self).__init__(parent)
        [...]

The complete example is attached.

Comment 1 Hugo Parente Lima 2010-10-18 15:46:23 EEST

You need to use the super passing the type of the current class, not the base
class, otherwise python will not initialize the QWidget, only QObject, so the
correct code is:


class Window(QtGui.QWidget):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)
        [...]

If we consider the code calling QObject constructor and not the QWidget
constructor valid, a lot of things will be wrong due to QWidget not being
initialized, e.g.:

class Bar(object):
    def __init__(self):
        print "Bar"

class Foo(Bar):
    def __init__(self):
        Bar.__init__(self)
        print "Foo"
        self.a = 5

class Window(Foo):
    def __init__(self):
        super(Foo, self).__init__()
        pass

w = Window()
# "a" member variable will not be initialized.
print w.a

Comment 2 Matti Airas 2010-10-21 05:19:13 EEST

Yep, my bad - didn't notice the incorrect type in the super call. I added a
notice about this to the Wiki:

http://developer.qt.nokia.com/wiki/Differences_Between_PySide_and_PyQt

Comment 3 Hugo Parente Lima 2010-11-25 17:53:39 EET

Released on version 1.0.0~beta1