Bug 427729

Summary:	Change theme with "use desktop layout theme" renders desktop to black screen
Product:	[Plasma] plasmashell	Reporter:	casquinhas <adelinoaraujo>
Component:	generic-crash	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	crash	CC:	nate, plasma-bugs-null
Priority:	NOR	Keywords:	regression
Version First Reported In:	master
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description casquinhas 2020-10-14 23:33:07 UTC

SUMMARY
updated to 5.20, rebooted, changed the theme for some I can't remember what it was, because I had a few installed. But the problem is to change the theme and select the option "use desktop layout theme". Every time I selected this option when changing theme, I always noticed that the Super key was disabled.
This time, I choose "use desktop layout theme" just to see if this was fixed and it was a total crash.

STEPS TO REPRODUCE
1. select (almost) any theme with "use desktop layout theme"
2. apply
3. desktop theme changes and 2 seconds later disappears; desktop is a dark, nothing on it

OBSERVED RESULT
both monitors are black, nothing on screen, no icons, no taskbar, no menus, no right-click menus, nothing

EXPECTED RESULT
theme was applied and kept running plasma with the new theme

SOFTWARE/OS VERSIONS
Windows:
macOS:
Linux/KDE Plasma: ArchLinux - 5.20
(available in About System)
KDE Plasma Version: 5.20
KDE Frameworks Version:
Qt Version:

ADDITIONAL INFORMATION
I cannot figure out what was the theme but this problem was on previous versions of plasma, but before I always lost the taskbar and Super key, but I managed to open systemsettings and change to Breeze and recover. This time, even if you change the systemsettings back to another theme with "use dekstop layout theme" and reboot, the desktop appears, the taskbar appears for 2 seconds and it's gone. I end up with a black screen. I also tried to edit some settings file to start plasma with breeze theme but nothing, it start with the theme that broke Plasma, that has the taskbar on top.
Plasma should make sure that the theme is applied and it is working. At least had a terminal option to start over with the default settings, so we could recover from this critical situation.
I managed to reboot and change some files by using another session ctrl+alt+f2 or f3. I also had xfce4 installed that I used to try to edit some files I found on .config but I could not find a single place where it says what files are the configuration of plasma.
This is not the first time that changing themes breaks plasma, but once again I will install plasma again soon as I backup my docs.
Selected critical severity because it renders the computer to blank.

Comment 1 Nate Graham 2020-10-16 18:30:12 UTC

Sounds like Plasma crashed if *everything* was black. Can you get a backtrace of the crash? See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports

When plasma has crashed, you can launch it again by typing "plasmashell" into KRunner, which hopefully is still running and can be shown with the Alt+space shortcut.

FWIW I cannot confirm the issue when switching to the Breeze, Breeze dark, or WhiteSur-dark global themes.

Comment 2 casquinhas 2020-10-19 21:04:56 UTC

"When plasma has crashed, you can launch it again by typing "plasmashell" into KRunner, which hopefully is still running and can be shown with the Alt+space shortcut."
Is was a total dark screen, meaning that no key you pressed would do anything. I tried yes all keys including for KRunner but alt+ctrl+del, and almost every other combination I could use. The only thing I could do was open another session ctrl+alt+f2 for example and reboot the machine. 
I tried to find what files were changed and revert it but it was impossible.

"FWIW I cannot confirm the issue when switching to the Breeze, Breeze dark, or WhiteSur-dark global themes."
I've always had problems in the past versions when I downloaded almost every theme and switched to that theme, like I said before.
Almost every time, I would loose the task bar. So I could only use KRunner or any shortcuts but that's not ok; I had to reboot every time, going to another session and reboot or use any opened terminal to reboot.

I might try to reproduce the problem on next weekend because I need the computer until then, but leave this open for now.
Yes, I have installed it again but now I don't have the time to recover if it goes wrong.

Comment 3 Bug Janitor Service 2020-11-03 04:33:35 UTC

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

Comment 4 Bug Janitor Service 2020-11-18 04:33:59 UTC

This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!