[PySide] Is Pyside 5.11 safe to use with Qt 5.15.2?

Cristián Maureira-Fredes Cristian.Maureira-Fredes at qt.io
Mon Jun 14 21:32:40 CEST 2021

Hey Olivier,

On 6/14/21 10:47 AM, Olivier B. wrote:
> I have been having trouble building Pyside 5.15.2. On windows, python 
> 3.5.2 crashes during the build, and on linux, i get another build error. 
> I will eventually look into those errors, but would like to know if in 
> the meantime i can safely use pyside 5.11 with qt 5.15?

PySide 5.15 is compatible with Python 2.7, and 3.5+
so it would be better for you to file a bug report,
and communicate the error so it can be solved or workaround.

Keep in mind that PySide was officially released in 5.12,
so on paper, you can take that as the initial stable version.
The path from there on was mainly to catch with missing API
and properly handling of Python's GIL,
so I would *highly recommend* you use 5.15.x

> The context of usage is:
> An application built with qt 5.15.2 that calls the python interpreter 
> using python libraries. Pyside 5.11 is installed in the modules 
> accessible by that application, excluding Qt dlls and plugins, so the 
> ones of Qt 5.15 used by the process are used. The uses of pyside in the 
> app are mostly to be used as a backend to draw matplotlib curves, and 
> some little usage for displaying simple dialogs. it seems to work, but 
> is there some hidden thing that could be problematic? 

If PySide 5.11 is installed...
was that built? or installed via pip?
it seems risky to play with that, but if it works at the moment,
and you cannot fix your build problems, I guess you can keep doing it,
but as mentioned before, there were some major issues that we fix in 
5.14.2, and are included in the following versions.

We usually recommend people to use the same Qt and PySide versions,
because at least with that we guarantee there will be no issues.


Dr. Cristián Maureira-Fredes
R&D Manager

The Qt Company GmbH
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D-12489 Berlin

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Juha Varelius, Jouni Lintunen
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