This simple program can crash Python:

import sys

from PySide import QtGui, QtCore

class MyPage(QtGui.QWizardPage):
   def initializePage(self):
      self.wizard()

app = QtGui.QApplication(sys.argv)

wizard = QtGui.QWizard()
page = MyPage()
wizard.addPage(page)
wizard.show()

The backtrace of the Python crash shows a stack overflow after
Shiboken::Object::Invalidate keeps recursing on itself, most likely because
QWizardPage and QWizard have some kind of circular dependency resulting from
calling QWizardPage.wizard().

This is reproducible on both Windows and Linux.

According to lmoura:

10:32 < lmoura> QWizardPage.wizard() is marking the page as parent of the 
                returned wizard

Which would account for the dependency loop.

To prevent such bugs from happening again, perhaps there could be an assertion
fired if circular parent relationships are established? (In this case between
QWizard and QWizardPage)