Bug 504469

Summary:	Klipper copies many unnecessary mime types
Product:	[Plasma] plasmashell	Reporter:	pbs3141
Component:	Clipboard widget & pop-up	Assignee:	Plasma Bugs List <plasma-bugs>
Status:	CONFIRMED ---
Severity:	normal	CC:	dezzadk, kde, nate, noahadvs, qydwhotmail
Priority:	NOR	Keywords:	efficiency-and-performance
Version First Reported In:	6.3.4
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=504470
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description pbs3141 2025-05-18 13:52:35 UTC

SUMMARY

When copying an object in Inkscape, Klipper requests the clipboard content in a large number of unnecessary mime types. Generating the extra formats makes copying noticeably slow and bloats clipboard history size.

This is a follow-up to

https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/5315
https://gitlab.com/inkscape/inkscape/-/issues/5528

STEPS TO REPRODUCE

1. Open Inkscape and observe calls to ClipboardManagerImpl::_onGet().
2. Draw a Rectangle.
3. Copy.

OBSERVED RESULT

The following mime types are requested:

text/plain
text/plain
image/png
text/plain
text/plain
image/png
text/xml+fxg
text/html
text/x-tex
text/xml+xaml
text/x-povray-script

EXPECTED RESULT

Only image/svg+xml should be requested.

SOFTWARE/OS VERSIONS

KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.9.0
Graphics Platform: X11

ADDITIONAL INFORMATION

The assessment at

https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/5315#note_1164002:
> Some MIME types like image/svg from Inkscape could cause it to hang because
> accessing data of the type means Inkscape will have to export the copied elements,
> and if there are many elements, it will explode.

is wrong; Inkscape does not explode because it is exporting too many elements (otherwise how would copy/paste have ever worked?), it is because Klipper is requesting export in every single advertised format - essentially a denial-of-service.

Inkscape advertises a large list of mime types to provide interoperability with programs that only understand those formats. The intent is definitely not that they should all be copied.

Only image/svg+xml needs to be copied in order to preserve the clipboard content losslessly, as all other formats are derived from that by exporting.

The latest fix (!5315) only reduced the list of requested formats; it is is still sufficiently long to make copying take a second. It also appears to contain duplicates, for some reason.

Comment 1 dezzadk 2025-07-13 20:58:29 UTC

Totally agree.

For this to have a purpose with xdg-mime, it needs to be AT LEAST assuming:

> text/*
types as well as their
> application/*
counterparts 
> x-ruby
> x-shellscript
> x-python3
To be actual pasteable, copyable text and NOT just
> text/plain

Relying on xdg-mime and its returned filetype breaks copying into klipper from almost any applications:
https://github.com/tmux-plugins/tmux-yank/pull/189
and to me its pretty clear that this is primarily upstream problem for the most part since it assumes so badly about all special chars. In tmux-yank's case its safe to assume as it factually text copied from terminal.

Terrible workaround - which isn't very logic:
> Configure > General Configuration > Non-text-selection: Never save in history

Actually means 'Do not use xdg-mime' - because it still stores copied files from Dolphin in the clipboard (oddly despite what is documented above).

A side-effect is also:

> Configure > Action Menu > Show action popup menu: Immediately on selection

and a configured shortcut:
> Configure > Shortcuts Configuration > plasmashell > Manually Invoke Action on Current Clipboard

Will not trigger when a different type is detected (which is totally random based on single special characters and far too uncertain)

Comment 2 dezzadk 2025-07-13 22:12:11 UTC

> Terrible workaround - which isn't very logic:
> > Configure > General Configuration > Non-text-selection: Never save in history
I retract that statement. It worked at the time, now its reversed. I will have to look more into the code.

Comment 3 dezzadk 2025-07-13 23:33:17 UTC

(In reply to dezzadk from comment #2)
> > Terrible workaround - which isn't very logic:
> > > Configure > General Configuration > Non-text-selection: Never save in history
> I retract that statement. It worked at the time, now its reversed. I will
> have to look more into the code.

With both settings klipper seems to go into a state where it assumes the next copied text is of the same mime-type is all I can infer from it.

Copying from vim with wayland support now randomly works - because it does not send a mime-type with it - exactly same issue as tmux-yank - so klippers functionality of auto-detecting via xdg-mime completely prevents normal clipboard operation.

Comment 4 pbs3141 2025-08-23 09:26:04 UTC

Let me add a third program affected in addition to Inkscape and Libreoffice: LyX.

Upon copying an equation, LyX hangs in lyx::cap::copySelection while consuming all available RAM, eventually crashing with a std::bad_alloc. During this time plasmashell is also frozen. I have verified that this behaviour does not happen on GNOME with the same LyX version.

We've now had to put in a hack in Inkscape specifically to work around this behaviour: https://gitlab.com/inkscape/inkscape/-/merge_requests/7252. It's still not as good as an upstream fix though, especially for the duplicate requests.