Moteus GUI Segfaults

[kylevernyi]

I am trying to run the moteus_gui / tview tools to connect to my moteus-c1 for the first time. I am following the instructions of the getting started video here.

I am running Fedora 40. I ran the pip3 install moteus-gui command successfully. When I run python3 -m moteus_gui.tview command I get the following seg fault:

[1] 8384 segmentation fault (core dumped) python3 -m moteus_gui.tview

I tried running gdb with gdb --args python3 -m moteus_gui.tview. I have attached the backtrace. backtrace.txt I put it into chatGPT and got the following which may or may not be correct:

The stack trace indicates that the segmentation fault occurs when Python is trying to call the PyType_Ready function with a NULL type pointer. This suggests that there is a problem with the initialization of a Python type object, possibly due to an issue with the shiboken6 library.

I reinstalled the shiboken6 library but it had no effect.

Thank you for the support.

[jpieper]

Hi! That is a known problem with pyside6.7. The pip packages require a version older than 6.7, but it looks like Fedora 40 has pyside 6.7 as a system package which you may have installed through yum. Are you familiar with using python virtual environments? If so, as a workaround you could use one with site packages disabled.

python -m venv --no-site-packages venv
venv/bin/pip install moteus-gui
venv/bin/tview

[jpieper]

For reference, the upstream bug we filed is: jupyter/qtconsole#605

[kylevernyi]

Wow thanks for the quick fix. I am running python3 so I had to change your command slightly to

python -m venv venv
venv/bin/pip install moteus-gui

Unfortunately PySide 6.6 was still installed in the venv for some reason. I did a manual update with

pip install PySide6 --upgrade

Confirmed with

python -c "from PySide6 import __version__; print(__version__)"

Got the output to be 6.7.2 which is what you mentioned needing.

Then I ran tview

And everything is working!

Thanks for the quick help. Looking forward to using these controllers. We are building a satellite simulator in my lab and are using these for the gyroscopes.

[jpieper]

Glad it is working for you! PySide 6.6 should work as that is what the wheel requests. At least 6.7.0 was broken, and I thought that Fedora 40 had 6.7.2 installed as the system package, but perhaps you have a different one or it has other patches that keep it broken.