feat(clipboard): support g:clipboard="osc52" #33021

Problem:
Forcing Neovim to use OSC52 for the system clipboard should be simple
and concise, since OSC52 is widely supported (Alacritty, Ghostty,
iTerm2, WezTerm, Kitty, xterm, tmux, etc.) and is the most portable
approach for syncing clipboards across SSH.

Solution:
Support g:clipboard="osc52".

2 files changed, 19 insertions, 5 deletions

diff --git a/runtime/autoload/provider/clipboard.vim b/runtime/autoload/provider/clipboard.vim
index 0bfd82f61d..abbd41d62a 100644
--- a/runtime/autoload/provider/clipboard.vim
+++ b/runtime/autoload/provider/clipboard.vim
@@ -59,6 +59,14 @@ function! s:split_cmd(cmd) abort
   return (type(a:cmd) == v:t_string) ? split(a:cmd, " ") : a:cmd
 endfunction
 
+function! s:set_osc52() abort
+  let s:copy['+'] = v:lua.require'vim.ui.clipboard.osc52'.copy('+')
+  let s:copy['*'] = v:lua.require'vim.ui.clipboard.osc52'.copy('*')
+  let s:paste['+'] = v:lua.require'vim.ui.clipboard.osc52'.paste('+')
+  let s:paste['*'] = v:lua.require'vim.ui.clipboard.osc52'.paste('*')
+  return 'OSC 52'
+endfunction
+
 let s:cache_enabled = 1
 let s:err = ''
 
@@ -69,6 +77,13 @@ endfunction
 function! provider#clipboard#Executable() abort
   " Setting g:clipboard to v:false explicitly opts-in to using the "builtin" clipboard providers below
   if exists('g:clipboard') && g:clipboard isnot# v:false
+    if v:t_string ==# type(g:clipboard)
+      if 'osc52' == g:clipboard
+        " User opted-in to OSC 52 by manually setting g:clipboard.
+        return s:set_osc52()
+      endif
+    endif
+
     if type({}) isnot# type(g:clipboard)
           \ || type({}) isnot# type(get(g:clipboard, 'copy', v:null))
           \ || type({}) isnot# type(get(g:clipboard, 'paste', v:null))
@@ -172,11 +187,7 @@ function! provider#clipboard#Executable() abort
   elseif get(get(g:, 'termfeatures', {}), 'osc52') && &clipboard ==# ''
     " Don't use OSC 52 when 'clipboard' is set. It can be slow and cause a lot
     " of user prompts. Users can opt-in to it by setting g:clipboard manually.
-    let s:copy['+'] = v:lua.require'vim.ui.clipboard.osc52'.copy('+')
-    let s:copy['*'] = v:lua.require'vim.ui.clipboard.osc52'.copy('*')
-    let s:paste['+'] = v:lua.require'vim.ui.clipboard.osc52'.paste('+')
-    let s:paste['*'] = v:lua.require'vim.ui.clipboard.osc52'.paste('*')
-    return 'OSC 52'
+    return s:set_osc52()
   endif
 
   let s:err = 'clipboard: No clipboard tool. :help clipboard'
diff --git a/runtime/doc/provider.txt b/runtime/doc/provider.txt
index 24ec170319..38bf6281d3 100644
--- a/runtime/doc/provider.txt
+++ b/runtime/doc/provider.txt
@@ -277,6 +277,9 @@ To disable the automatic detection, set the "osc52" key of |g:termfeatures| to
 To force Nvim to always use the OSC 52 provider you can use the following
 |g:clipboard| definition: >lua
 
+    vim.g.clipboard = 'osc52'
+
+Which is equivalent to: >lua
     vim.g.clipboard = {
       name = 'OSC 52',
       copy = {