[PyQt] Issue with multiple inheritance

[Phil Thompson]

On 20 Jan 2017, at 8:43 pm, Dmitry Shachnev <mitya57 at ubuntu.com> wrote:
> 
> Hi all,
> 
> I am trying to write a class that inherits from two parent classes: one from
> Qt and one mine.
> 
> The minimal example is:
> 
> -----------------------------------
> from PyQt5.QtCore import QObject
> 
> class AnotherBase:
>    def __init__(self, foo):
>        pass
> 
> class MyView(QObject, AnotherBase):
>    def __init__(self, foo):
>        QObject.__init__(self)
> 
> MyView('foo')
> -----------------------------------
> 
> When I try to run it (with the latest sip and PyQt releases), I get this:
> 
> Traceback (most recent call last):
>  File "./test.py", line 11, in <module>
>    MyView('foo')
>  File "./test.py", line 9, in __init__
>    QObject.__init__(self)
> TypeError: __init__() missing 1 required positional argument: 'foo'
> 
> Which sounds strange to me. Why should QObject.__init__ take my argument?
> 
> This does not happen when I replace QObject with my own another base class.
> This also does not happen if I change the order of inheritance: first
> AnotherBase, then QObject.
> 
> Is it my misunderstanding or a bug somewhere? (I hope for the former.)

http://pyqt.sourceforge.net/Docs/PyQt5/multiinheritance.html#support-for-cooperative-multi-inheritance

Phil