Bug 439831

Summary: Resizing the window is slow when the buffer contains a very long line
Product: [Applications] konsole Reporter: Louis Moureaux <m_louis30>
Component: kpartAssignee: Konsole Developer <konsole-devel>
Status: RESOLVED FIXED    
Severity: normal CC: a.samirh78, cbc.alves
Priority: NOR    
Version: 21.04.3   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: https://invent.kde.org/utilities/konsole/-/commit/2aa61bb9943c4e00d1764fa45f2c210cc92a41de Version Fixed In: 21.08
Sentry Crash Report:

Description Louis Moureaux 2021-07-14 09:30:50 UTC 
SUMMARY

When the buffer contains a long line, resizing the terminal window takes several seconds.

STEPS TO REPRODUCE
1. Open Konsole
2. Run the following to output a long line of text (change 10000 to something larger if your machine is very fast):

   python3 -c 'print([x for x in range(10000)])'

3. Resize the window

OBSERVED RESULT

Resizing the window takes seconds, even when the line is hidden from view.

EXPECTED RESULT

Resizing the window is instantaneous.

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.22
KDE Plasma Version: 5.22.3
KDE Frameworks Version: 5.84.0
Qt Version: 5.15.3
Kernel Version: 5.8.0-59-generic (64-bit)
Graphics Platform: X11
Comment 1 Carlos Alves 2021-07-18 22:54:52 UTC 
This problem was fixed in master branch since this commit: 
 https://invent.kde.org/utilities/konsole/-/commit/2aa61bb9943c4e00d1764fa45f2c210cc92a41de
Comment 2 Ahmad Samir 2021-07-19 00:34:23 UTC 
FWIW, I used:
$ git fetch --all
$ git tag --contains 2aa61bb9943c4e00d1764fa45f2c210cc92a41de
v21.07.80

(IIRC I picked the tip about --contains from somewhere on the KDE mailing lists, I think it was Aleix on plasma-devel, handy tip :)).