Bug 408986

Summary:	Previews for plain text files no longer work.
Product:	[Frameworks and Libraries] kio-extras	Reporter:	3ndymion <3ndymion>
Component:	Thumbnails and previews	Assignee:	Friedrich W. H. Kossebau <kossebau>
Status:	RESOLVED UPSTREAM
Severity:	normal
Priority:	NOR
Version First Reported In:	19.04.0
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description 3ndymion 2019-06-21 11:38:53 UTC

SUMMARY
The previews for plain text files no longer work.  These are the previews that show when you hover the mouse cursor over a file.  They suddenly broke about a month or 2 ago.  They work fine for other files, such as shell scripts, but they only show a blank page preview for any plain text file, such as textfile.txt, or even just textfile (no extension).  If I change the file name to textfile.sh, the preview works fine.

Previews are set for text files in Dolphin preferences.  I tried unchecking & checking it again, but the problem persists.  Clicking the preview button at the top does not fix it, nor does changing the size of the icons.  Clicking show preview in Adjust view properties does not fix it either.

STEPS TO REPRODUCE
1. Hover mouse cursor over text file icon.
2. 
3. 

OBSERVED RESULT
The preview popup shows a blank page.

EXPECTED RESULT
The preview popup should show a preview of the text in the file.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux 5.1.12-arch1-1-ARCH
(available in About System)
KDE Plasma Version: 5.16.1
KDE Frameworks Version: 5.59.0
Qt Version: 5.12.4

ADDITIONAL INFORMATION

Comment 1 Higa 2019-06-22 11:18:38 UTC

I can confirm this.

After reverting af7c2b4, 4b19435 and d95ff83 [1] [2] and recompiling kio-extras, previews for plain text files work again.

[1] https://github.com/KDE/kio-extras/commits/master/thumbnail/textcreator.cpp
[2] You can use the command "git revert af7c2b4 4b19435 d95ff83".

Comment 2 Friedrich W. H. Kossebau 2019-06-22 11:40:04 UTC

Hi. What color scheme do all of you use for the UI? And can you test if things improve with another scheme (ideally needs a fresh restart of Plasma, to make sure the setting change is in effect and no cache is hit).
Asking because this sounds a bit like bug 406821 , but that one should be fixed with KDE Frameworks 5.59, which at least you, 3ndymion, seem to have.

Comment 3 Higa 2019-06-22 11:53:58 UTC

I am using Breeze Dark.

After switching to Breeze and re-login, previews for plain text files work.
If I switch back to Breeze Dark and re-login, and previews for plain text files no longer work.

Comment 4 Friedrich W. H. Kossebau 2019-06-22 12:08:01 UTC

Higa, thanks for testing. Can you please also tell which version of ksyntaxhighlighting you have? Really 5.59?

Comment 5 Higa 2019-06-22 12:24:38 UTC

(In reply to Friedrich W. H. Kossebau from comment #4)
Yes, I have syntax-highlighting 5.59.0-1 built by Arch Linux.

Comment 6 Friedrich W. H. Kossebau 2019-07-01 17:00:35 UTC

Having Qt 5.13 and KF 5.59 (openSUSE TW) on my working system, I sadly can now confirm this behaviour again. So far would assume something changed Qt side, as this was behaving well on the same system with older Qt (and own build of KF 5.59) before.

I created a dedicated bug now for ksyntaxhighlighting as this might need fixing on their side again I assume: bug 409380
And thus close this report for now as upstream issue.