Bug 424738

Summary:	Scrollback buffer gets partially deleted after pressing "Ctrl+L"
Product:	[Applications] konsole	Reporter:	ParsaMousavi <sepamou>
Component:	history	Assignee:	Konsole Bugs <konsole-bugs-null>
Status:	CONFIRMED ---
Severity:	normal	CC:	kevin.legouguec, kubry, spiked.yar, tcanabrava, zhiweik
Priority:	NOR	Flags:	sepamou: Usability+
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description ParsaMousavi 2020-07-28 08:54:04 UTC

Just after a recent upgrade,Konsole doesn't retain the scrollback buffer correctly anymore and the last X lines of it(where "X" is the row size of the terminal,24 by default) gets deleted from the buffer after pressing "Ctrl+L".This happens in a fullscreen(by pressing "F11") terminal window too.Also the "clear" command makes the buffer disappeared completely.

STEPS TO REPRODUCE:

1. Open the Konsole terminal emulator

2. Issue a command that generates a relatively long output(i.e more lines than the number of terminal window rows)

3. Press "Ctrl+L" and check the scrollback buffer again



SOFTWARE/OS VERSIONS:

Linux/KDE Plasma: 5.3.0 / KDE Neon Unstable
KDE Plasma Version: 5.19.80
KDE Frameworks Version: 5.73.0
Qt Version: 5.14.2

Comment 1 tcanabrava 2020-07-28 09:35:21 UTC

Confirmed for master.

Comment 2 tcanabrava 2020-07-28 09:36:33 UTC

a sidenote, clear should make the buffer disappear completely, it's a clear after all. the old behavior of konsole to just add lines to the scrollback buffer was buggy.

Comment 3 Misha Labjuk 2021-10-20 22:10:07 UTC

(In reply to tcanabrava from comment #2)
> the old behavior of konsole to just add lines to the scrollback
> buffer was buggy.

Could you explain why buggy?

xterm and konsole 21.04.3 delete text to clear.
alacritty, screen, gnome-terminal use scroll to clear.

May be create preference to select behavior?
I want to save all output to scrollback.

Comment 4 tcanabrava 2021-10-21 08:57:29 UTC

because it's a "Clear Scrollback" not a "Add Newlines".
A "Clear Scrollback" that does not clear's the scroolback will certainly have bugs opened for that.

We *can*, however, add a new option "Scroll to the top" or something.
Are you willing to try to implement such feature?

Comment 5 Misha Labjuk 2021-10-21 21:08:08 UTC

(In reply to tcanabrava from comment #4)
> Are you willing to try to implement such feature?
Yep.

I am concerned by https://bugs.kde.org/show_bug.cgi?id=384218

Comment 6 kchen 2022-08-04 05:17:26 UTC

I also encounter this issue, the behavior I encountered is weird, sometimes it erase all the scrollback buffer, sometimes is only erase the last command and it's output.

Could you please restore the behavior? Or add a new option like tcanabrava said "scroll to top"?