Dolphin doesn't show folder preview on local file system unless you enter once in the particular folder so the system can read the files. And what interestring is, the prevew is gone on restart and one have to enter again in the folder in order Dolphin to show a preview again.
STEPS TO REPRODUCE
1. Put some files in a folder - png, jpeg, exe, etc.
There's no folder preview unless you enter once in that folder.
There's should be folder preview without the need to enter the particular folder,
KDE Plasma Version: 5.24.5
KDE Frameworks Version: 5.93.0
Qt Version: 5.15.3
What is the filesystem being used? EXT4 or NTFS or something else?
Ah sory - it's ext4 :)
OK, probably not that bug, then. I can reproduce it.
It's other bug, yeah :)
It's a bug in the thumbnail KIO which creates the directory thumbnails. Loading from cahce works but generation of new ones does not work. This is why the thumbnails start showing up after having entered the directory because the thumbnails are generated properly then.
Bug is in https://invent.kde.org/network/kio-extras/-/blob/master/thumbnail/thumbnail.cpp#L734 where "subPlugin" is the path to the .so file whereas m_enabledPlugins contains a list of IDs, so this check never passes and no thumbnail is generated.
Git commit ab2660f22e7692c1bc35d63048704a65f3b5e84d by Alexander Lohnau, on behalf of Martin T. H. Sandsmark.
Committed on 07/06/2022 at 15:51.
Pushed by meven into branch 'master'.
Fix creating thumbnails for folders
Thanks to Kai Uwe Broulik for debugging (which I saw too late, but oh
M +12 -11 thumbnail/thumbnail.cpp
M +2 -1 thumbnail/thumbnail.h
Thank you very much!
Thanks for all the hard work on this annoying bug.
I was hoping it would be resolved after today's updates to KDE Plasma 5.25 and KDE Frameworks 5.95 but it's unfortunately not.
On my machine Dolphin behaves just like on Nick's machine with photos. However with videos Dolphin will successfully generate thumbs for them in all subfolders. If you enter a subfolder and then go up again then Dolphin will start displaying thumbs for photos as well only for that folder you have entered.
I tried to reset Dolphin settings to defaults and that didn't work too.
Anything else to be done? Thanks again!
Operating System: KDE neon 5.25
KDE Plasma Version: 5.25.0
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.4
The fix is in Dolphin/kio-extras 22.08, which hasn't been released yet.
Glad to hear that the fix is coming and thanks for the quick reply. Sorry I'm new and couldn't find any more info on kio-extras. Would appreciate any links to releases or schedule or code bases for it. Thanks again.
It's got the same release schedule as Dolphin, so assuming you have it installed, you'll get the fix when you upgrade to Dolphin 22.08.
Thanks again for all the info!
(In reply to Nate Graham from comment #12)
> It's got the same release schedule as Dolphin, so assuming you have it
> installed, you'll get the fix when you upgrade to Dolphin 22.08.
I really can't find any release shedule for Dolphin. Can you give some help?
Dolphin is on the common KDE Gear release schedule used by most KDE apps at this point. See https://community.kde.org/Schedules
22.08 isn't listed there yet, but the numbering gives you a clue as to when it will be released: the 8th month of 2022. So about two months from now.
Oh, thank you very much :)
Downgrading kio-extras to version 21.12 in combination with dolphin 22.04 works for me on Fedora 36. Don't forget to add a version-lock.
I can confirm that the problem is fixed in Dolphin 22.08!