osc52 support should use the TTY of the TUI client, not the backend

[j-xella]

Problem

It seems to me that the osc52 copying is run completely on the back-end side. This does not really matter for quick nvim sessions, when both back and TUI parts are running in the same shell. But in cases when the back-end is treated as a server (in my case to preserve my session during disconnects) it could lead to copying via osc52 being broken.

I believe osc52 functionality should be invoked in the terminal TUI is running in.:

• Either the logic should be invoked in TUI part of nvim
• Or the back-end should have access to the terminal of the TUI and use it

Steps to reproduce

You need 2 terminals, one with (T1) and the other without (T2) osc-52 support.

In T1, if you just run nvim, and from there

:=require('vim.ui.clipboard.osc52').copy('+')({'test1'})

The text test1 should appear on the clipboard.

Now, start the neovim backend in T2 :

nvim --headless --listen xxxxx

And connect to it from T1 :

nvim --server `fd xxxxx /tmp/nvim.$(id -nu)` --remote-ui

If you try putting something on the clipboard now using the require command above, it does not work any more.

Expected behavior

Because we are working in T1 which supports osc-52 , copying should work.

Neovim version (nvim -v)

NVIM v0.10.0-dev-2658+g0f85aeb47

Vim (not Nvim) behaves the same?

not applicable

Operating system/version

Linux RHEL 7.9

Terminal name/version

wezterm as T1, xterm as T2

$TERM environment variable

wezterm and xterm respectively

Installation

build from repo