Ulauncher: Crash when switching workspaces while launcher is open

[bass0n]

Steps to reproduce:
Open launcher
Switch to another workspace

Ulauncher version: v4.3.1.r4
Linux distro: Ubuntu 18.04.2
Desktop environment: Gnome 3.28.2
Additional Info
Probably not related, but could be worth noting I use xrandr to scale down UI, which is upscaled natively by Gnome to 200% (because screen ppi is 157 which doesn't look good with standard scaling options).

Logs:
https://gist.github.com/bass0n/bfad5ab8b3908703dd285342c31f8fc4

[friday]

I tried to reproduce this (without xrandr), using ctrl + alt + up/down. It worked as expected for me. I don't have an actual button for switching workspaces and forgot how I disabled it by now.

Can you confirm that it's Ulauncher (not Xrandr, X11, Gnome or something else) which crashes, and that the process stops? If you try to open Ulauncher with the keyboard combination afterwards, it doesn't do anything I take it?

Sorry for the potentially stupid questions, but normally Python shows the error(s) when there's a crash.

[bass0n]

Well, that's unfortunate, will try again once home. I am not sure it's completely launcher's fault either, system freezes for a bit, then Gnome restarts itself(UI disappears and renders back again), and launcher is accessible like nothing happened. I'll try to check Gnome logs as well, but guess for now I'll just have to remember not to trigger the crash.

[gornostal]

Looking at this line in the log I think it may be due to some weird character being inserted into the Ulauncher query input while switching workplaces.

/usr/lib/python2.7/dist-packages/ulauncher/api/server/ExtensionServer.py:90: UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal

I'll see how that can be fixed.
Thanks for reporting this bug, btw.

[friday]

Looking at this line in the log I think it may be due to some weird character being inserted into the Ulauncher query input while switching workplaces.

The log dates are all within a very short time span (looks like it happened while starting Ulauncher imo), and it says it interpreted it as non-equal, so I dismissed that warning as a red herring. I hope I'm wrong though :+1:

I think getting some logs specifically from the process that crashed (probably gnome-shell?) would be helpful still.

With systemd this should get the logs within a specific time frame (the last half hour in this example): journalctl /usr/bin/gnome-shell --since -30m. Your system may be different though, and if it's not gnome-shell that crashes that won't help of course.

[jmilne22]

I was able to reproduce this on my machine, haven't done anything special to my system, it's basically a stock ubuntu 18.04 setup. The system hard locks before gnome restarts on one occasion it just logged me out of the system.

Ulauncher version: v4.3.2.r8
Linux distro: Ubuntu 18.04.2
Desktop environment: Gnome 3.28.2

I've attached the log file from the command journalctl /usr/bin/gnome-shell --since -30m to see if anyone can gather anything from it.

err.txt

[friday]

@jmilne22 That's helpful!

It looks like your gnome shell crashed three times within this time span in the log. The exact same error and stack trace is here in a supposedly fixed issue: https://gitlab.gnome.org/GNOME/gnome-shell/issues/414 which came out after Gnome 3.28.2, which you're both using.

I would suspect Gnome 3.30 would fix this issue for both of you if you can safely upgrade? This would also explain why I can't replicate the issue.

[friday]

Judging by that error and the source code in keyboard.js it looks very much like it's caused by the handler for the keyboard "focus" (cursor location), which makes sense too imo. Since this is seemingly only caused with Ulauncher open in both of your systems, maybe there's something unorthodox Ulauncher is doing or not doing to gain or keep the focus (like this timeout)?

[bass0n]

Hey guys, sorry for abandoning the thread. Issue seems to only exist on Gnome 3.28 and maybe below, so upgrading to 3.30(by switching to Ubuntu 18.10) seems to do the trick, at least for me(same hardware). Unfortunately, users of Ubuntu 18.04 have no simple means of upgrading to a newer Gnome though.

[friday]

Thanks for confirming @bass0n