Bug 426837

Created attachment 131845 [details]
Screenshot of text file previews

SUMMARY
I have previews for text files enabled, and when I first installed the system, they did work perfectly. After a few days of running, though, *some* text files are now showing blank preview images. (See attached screenshot.) It seems to depend on the file extension. If the file ends in .txt or has no extension at all, the preview is blank. But other text file extensions such as .cfg, .dat, and .ini are working perfectly.

See the attached screenshot -- in this screenshot, all five text files are exactly identical copies of each other and differ only in the filename. Three show perfect preview images, but two show blank previews. (All other file type previews are working perfectly.)

When text files are placed on the desktop, it shows the icon for a text file and doesn't attempt to preview them -- don't know if that's relevant or not.

This seems similar to bug #113572 https://bugs.kde.org/show_bug.cgi?id=113572 but I thought I'd put it up as a new bug since that one is 15 years old and has been marked as not reproducible.

Using Kubuntu 20.04

Tried several cold reboots; problem persists.
Tried disabling text file previews and re-enabling it; problem persists.

STEPS TO REPRODUCE
1. create several identical text files, one with no file extension, and one each with .txt, .cfg, .ini, .dat
2. enable text file previews and view the folder these text files are in
3. (hopefully) observe that the text file with the blank extension and the one with the .txt extension show blank preview images, while the other three show correct preview images

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 20.04
(available in About System)
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8