wayland support in wheels on Pypi

[Sergio Callegari]

I have digged a little further.

On 19/02/2025 23:33, Sergio Callegari wrote:
> Debugging as suggesting reveals that, as suspected, |pyqt5-qt5| does not 
> contain the wayland plugin, that is not in the wheel for this package.

It is my understanding that the wheels for pyqt5-qt5 on pypi are built 
using the PyQt-bundle tool, part of PyQt-builder. Can this be confirmed?

I also understand that PyQt-builder is available from Pypi, so one can 
install it and so get the pyqt-bundle command line tool. Is this correct?

Once one has this, it should be possible to run pyqt-bundle against your 
system QT library directory, and the pyqt-bundle should be able to pick 
the relevant part and make a wheel of it. If I get it right, this should 
be the way in which the PyQt5-Qt5 wheels present on Pypi are built by 
Phil Thompson, who is also the maintainer of the pyqt-builder framework. 
Right?

Now, assuming that the above points are right (my apology if they are 
not), there are still a few missing points for me.

1) Why does the "official" pyqt5-qt5 wheel from pypi miss the qt wayland 
plugin? is the bundle tool explicitly excluding it or is the wheel built 
from a QT distribution without it? In the latter case, would it be 
possible to update the wheel to also include the wayland plugin?

2) Alternatively, do python packages have something like the 'provides' 
concept that most linux distro packaging systems have? In other words, 
would it be possible to have on pypi a pyqt5-qt-wayland package that 
provides pyqt5-qt also including the wayland plugin?

3) Alternatively, can I use the pyqt-bundle cli tool to build my own 
pyqt5-qt5 wheel based on my system's qt5 that includes the wayland 
plugin and use that to satisfy the dependencies of other packages?

4) And finally: would it be possible to create a 'fake' pyqt5-qt5 
package to be used only locally merely pointing at the system qt5 
installation, without duplicating it?

Thanks,
Sergio


> Trying to point to my system QT5 plugins does not work either. They are 
> recognized but they are not binary compatible, there must be some 
> difference in the toolchain.
> 
> The pyqt5-qt5 package is said to contain the subset of a Qt installation 
> that is required by PyQt5. As of today that should probably include also 
> the wayland plugin, or there should be another package on pypi providing it.
> 
> Any clue?
> 
> Sergio
> 
> On 17/02/2025 09:32, Charles wrote:
> 
>> Just set QT_DEBUG_PLUGINS [1], check where it tries to load the 
>> plugins, and if it is a wrong path, fix it using the methods in [2].
>>
>> As a python application it isn't always clear where the application 
>> path is which is used to load the plugins.
>>
>> [1] https://doc.qt.io/qt-6/debug.html#environment-variables- 
>> recognized-by-qt
>> [2] https://doc.qt.io/qt-6/deployment-plugins.html
>>
>> On Mon, Feb 17, 2025 at 3:07 PM Sergio Callegari 
>> <sergio.callegari at gmail.com> wrote:
>>
>>     Hi,
>>
>>     I have noticed a strange behavior from applications using PyQt5
>>     and PyQt5-Qt5 (seen using the python IDE spyder).
>>
>>     When I run spyder after having installed it from the packages
>>     provided by my distribution (manjaro), spyder runs as a wayland
>>     application on my system.
>>
>>     However, if I install spyder using pip, uv, or pipx (namely
>>     installation methods that rely on pre-built wheels from pypi),
>>     then spyder cannot run anymore as a wayland application. From its
>>     logs, I see that it cannot find the appropriate Qt plugin:
>>
>>     Could not find the Qt platform plugin “wayland” in “”
>>
>>     Now I wonder if there might be something missing in the pre-built
>>     wheels of PyQt5 distributed on Pypi.
>>
>>     Being able to have Qt applications working as wayland applications
>>     could be beneficial on systems with two displays with different
>>     resolutions, which is a setup not well supported by some
>>     compositors with Xwayland.
>>
>>     Thanks for the attention and your help,
>>
>>     Sergio
>>
>>     ​
>>
> ​