[PyQt] PyQt 5.7.1 SystemError exceptions on import

Phil Thompson phil at riverbankcomputing.com
Mon Nov 14 10:12:20 GMT 2016

On 14 Nov 2016, at 3:44 am, Shawn Douglas <shawn.douglas at gmail.com> wrote:
> Hi,
> I ran into some import issues with PyQt5 5.7.1 dev1611100918. No problems observed with version 5.7. Using Python 3.5.2 in both cases.
> The errors arise when importing a class that multiply inherits from QMainWindow and a pyuic5-generated class from a .ui file. Here's the output:
> SystemError: Objects/typeobject.c:2832: bad argument to internal function
> During handling of the above exception, another exception occurred:
> Traceback (most recent call last):
>   File "cadnano/bin/main.py", line 57, in <module>
>     main()
>   File "cadnano/bin/main.py", line 36, in main
>     app = initAppWithGui(argv, do_exec=False)
>   File "./cadnano/__init__.py", line 47, in initAppWithGui
>     shared_app.finishInit()
>   File "./cadnano/cadnanoqt.py", line 93, in finishInit
>     from cadnano.gui.controllers.documentcontroller import DocumentController
>   File "./cadnano/gui/controllers/documentcontroller.py", line 14, in <module>
>     from cadnano.gui.views.documentwindow import DocumentWindow
>   File "./cadnano/gui/views/documentwindow.py", line 22, in <module>
>     class DocumentWindow(QMainWindow, ui_mainwindow.Ui_MainWindow):
> SystemError: <class 'sip.wrappertype'> returned a result with an error set
> For reference, the .ui and ui_.py files are here: 
> https://github.com/cadnano/cadnano2.5/tree/master/cadnano/gui/ui/mainwindow
> pyuic5 versions 5.7 and 5.7.1dev generate identical outputs, except for the "Created by:" line. 
> I found the SystemError exceptions go away if I modify my DocumentWindow class to singly inherit from either class, but obviously that breaks the application, so maybe there is an issue with how class args are being handled.
> Any suggestions for how to track down this issue would be appreciated.

Should be fixed in tonight's PyQt5 snapshot.


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