Running as root breaks, working fine as normal user

[evergreenbear]

Environment

• OS: Void Linux
• web-greeter version: 3.3.0

Bug description

Running web-greeter --debug as normal user works fine, but there is an error saying "QWidget: Must construct a QApplication before a QWidget" when running with escalated privileges. This causes LightDM to infinitely loop.

Steps to reproduce

Run "web-greeter --no-sandbox" or "web-greeter --debug" as root.

Expected behavior

web-greeter would work while running as root.

Screenshots

[evergreenbear]

Reinstalled with the latest commit, I'm now getting "Could not find QtWebEngineProcess" when running as root.

[JezerM]

How did you install web-greeter? void-packages should work.

[evergreenbear]

I installed it by cloning the github repo and running sudo make install

[JezerM]

Well, I mean, which packages did you install?

The following should do it:

sudo xbps-install python3-PyQt5 python3-PyQt5-webengine python3-ruamel.yaml python3-gobject python3-xlib python3-inotify python3-PyQt5-devel-tools qt5-webengine

[evergreenbear]

Looks like I was missing ruamel and inotify system-wide, but after installing them it still can't find QtWebEngineProcess

[JezerM]

Hmm, that's weird. Did you install these packages with PIP? If you did, you could try to uninstall them and just rely on void packages.

The QtWebEngineProcess should be inside /usr/lib/qt5/libexec/QtWebEngineProcess, from the qt5-webengine package; you can find it with xbps-query -f qt5-webengine | grep -i process. Maybe, try to reinstall web-greeter's packages.

[evergreenbear]

After reinstalling the packages, I'm getting a new error:
/usr/lib/python3.10/site-packages/PyQt5/QtWebChannel.abi3.so: undefined symbol: _ZdlPvm, version Qt_5

[JezerM]

See the Import errors section of the README. Perhaps, you could try reinstalling qt5-webchannel and python3-PyQt5-webchannel.

[evergreenbear]

Reinstalled, same issue.

[JezerM]

Well, there's no much I could do about it. Reinstalling is the only solution to this kind of problem: remove related PIP packages inside /usr/lib/python3.10/site-packages/ and ~/.local/lib/python3.10/site-packages/, and reinstall with xbps-install --force. If it doesn't work, maybe you should create an issue either in void-packages or Qt.

However, after doing a little research, seems like the problem comes from the python3 Qt libraries, with the next possibilities:

• They weren't compiled to your current Python version.
• You did upgrade Python, but Qt libraries weren't recompiled.
• Root and user have different libraries or a different Python version (maybe homebrew or other services are interfering)

So, you could try to recompile your Python libraries (though I don't know how to do it), or reinstall all Python Qt related libraries.