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
I can't reproduce that error message in particular but activity thumbnails seem to indeed be broken
edit: i can reproduce the issue also with the error message
Can also confirm.
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