Bug 483448

Summary:	"undocmented error" reported by plasmashell when Activity Manager ecounters local image as wallpaper on activity desktop: "SwitcherBackend: FAILED to get the thumbnail"
Product:	[Plasma] plasmashell	Reporter:	Hugh Kernohan <hugh.kernohan>
Component:	Activity Switcher sidebar	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	CONFIRMED ---
Severity:	normal	CC:	hugh.kernohan, ivan.cukic, nate, notmart, wolf
Priority:	NOR	Keywords:	qt6, regression
Version First Reported In:	6.0.1
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Hugh Kernohan 2024-03-13 15:15:41 UTC

SUMMARY

When a local image is the wallpaper on activity desktop, using Activity Manager produces "undocmented error" and  "SwitcherBackend: FAILED to get the thumbnail"

STEPS TO REPRODUCE
1. Create new activity
2. Configure Desktop and Wallpaper
3. Add Image:  JPEG from local harddisk
4. Save and exit
5. Open Activity Manager from main Panel

OBSERVED RESULT
New image is displayed in Activity Manager, but journalctl reports:

Mar 13 14:38:17 plasmashell[1397]: SwitcherBackend: FAILED to get the thumbnail 
"Unknown error code 0  Please send a full bug report at https://bugs.kde.org." 
QList("Undocumented Error", "<qt><p><b>Undocumented Error</b></p><p>Unknown error code 0\n\nPlease send a full bug report at https://bugs.kde.org.</p></qt>", "<qt><p><b>Details of the request</b>:</p><ul><li>URL: (unknown)</li><li>Date and time: Wednesday, 13 March 2024 14:38:17 UTC</li><li>Additional information: </li></ul></qt>")

EXPECTED RESULT
No error is reported

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.0.1
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.7.9-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 6 × Intel® Core™ i5-8600 CPU @ 3.10GHz
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 6650 XT

ADDITIONAL INFORMATION

Comment 1 Marco Martin 2024-03-13 15:48:58 UTC

I can't reproduce that error message in particular but activity thumbnails seem to indeed be broken

Comment 2 Marco Martin 2024-03-13 16:00:54 UTC

edit: i can reproduce the issue also with the error message

Comment 3 Nate Graham 2024-03-13 21:02:16 UTC

Can also confirm.

Comment 4 Wolfgang Müller 2024-11-07 16:33:23 UTC

I can confirm with 6.2.3, but I think the description is slightly wrong. From my testing it is not local images that trigger this error, but built-in wallpapers. This is because a built-in wallpaper will be referenced by a directory "/usr/share/wallpapers/Next" instead of a path to an actual image. Passing a directory to KIO:filePreview [1] will then make it fail.

[1] https://invent.kde.org/plasma/plasma-desktop/-/blob/7d2e16b09d391b7bc979e447d21bc8747399c55d/imports/activitymanager/switcherbackend.cpp#L98