Confusing interaction between xsel and qubes clipboard

[cryslith]

Qubes OS version: R4.0

Affected component(s) or functionality: Clipboard

Brief summary: Attempting to copy >4000 bytes between VMs using xsel results in confusing message.

To Reproduce

1. Open any AppVM
2. Run python3 -c 'import sys; sys.stdout.buffer.write(b"A" * 4001)' | xsel -ib
3. Press Ctrl+Shift+C

Expected behavior
Data should be copied properly; alternatively, an explanatory error message should be displayed.

Actual behavior
Popup message says "Copied 1 byte to the clipboard." and nothing is copied.

Workaround
One solution to copying large amounts of data in general is to use the qvm-copy command. Another workaround is to use the window manager's usual copying UI instead of using xsel.

Relevant documentation you've consulted

• https://www.qubes-os.org/doc/copy-paste/ makes no mention of any size limit, nor does it point out that you should use qvm-copy to copy large amounts of data.

Related, non-duplicate issues

• Qubes Clipboard transfer limited size of text #5220 Not a duplicate, since that issue is about a different 65kb limit.

[marmarek]

This seems to be an issue with xsel. If I print it to the console, then copy from there, 4001 bytes are correctly copied.
But when I try to copy 66kb, only first 65000 bytes are copied and so says the message (nothing about exceeding the limit).

[cryslith]

Oops, you're right. I thought I tried that. Edited the issue.

[rootnoob]

I think my issue I discovered some-time has the same root-cause (sorry if this needs a new issue).

Attempting to ctrlc-ctrlshiftc from firefox dvm to ctrlshiftv-ctrlv to gedit results, (> rougly 65000 bytes, as @marmarek said), results in exactly '1 byte (dom0 notification)' being copied to the global clipboard; and 1 letter (the same letter every single time) being pasted into gedit.

[github-actions]

This issue is being closed because:

• This issue is on the "Release 4.0 updates" milestone.
• Qubes OS 4.0 reached EOL (end-of-life) over one year ago.
• There has not been any activity on this issue in over one year.

If anyone believes that this issue should be reopened and reassigned to an active milestone, please leave a brief comment.
(For example, if a bug still affects Qubes OS 4.1, then the comment "Affects 4.1" will suffice.)