QT vs pyside versions

[efferre]

Freecad can be compiled against Qt4 or Qt5, the two frameworks are supported by pyside and pyside2 respectively. Freecad compiled with BUILD_QT5 seems to work without problems with python scripts using pyside (and not pyside2). It seems someone is doing some magic behind the scenes, here is what I see in the python console:

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>>> import PySide
>>> PySide.__version_info__
(5, 9, 0, 'a', 1)
>>> import PySide2
>>> PySide2.__version_info__
(5, 9, 0, 'a', 1)

So effectively the two modules look the same. Furthermore:

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>>> from PySide import QtGui
>>> QtGui.QMessageBox()
<PySide2.QtWidgets.QMessageBox object at 0x7f66fd7c8200>
>>> from PySide2 import QtGui
>>> QtGui.QMessageBox()
Traceback (most recent call last):
  File "<input>", line 1, in <module>
AttributeError: 'module' object has no attribute 'QMessageBox'

It seems that when using PySide there is a compatibility layer that converts automatically to qt5 code.

Can someone explain what happens and how this works? Is it better to code python scripts with pyside or pyside2?

[looo]

We use an layer on top of PySide2 to make python stuff done with PySide compatible with PySide2.
Here the magic parts are introduced: https://github.com/FreeCAD/FreeCAD/blob ... #L991L1001

I think we officially support the old PySide-API and if you want to make addons compatible with PySide and PySide2 it's best to use the old API.

[efferre]

Thank you for the clarification, now it is clear. PySide installed on the system is masked by the wrapper shipped with FreeCAD:

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>>> import PySide
>>> PySide.__path__
['/usr/share/freecad-0.17/Ext/PySide']
>>> import PySide2
>>> PySide2.__path__
['/usr/lib64/python3.5/site-packages/PySide2']