fix(extui): adjust "more" window routing (#34251)

Problem:  Message lines from multiple message events that end up
          spilling 'cmdheight' end up spread out over the cmdline
          and "more" window.
          Messages emitted as feedback to a typed :command (rather than
          its sole purpose like :echo/:=) are routed to the more window.
          The more window isn't closed when entering the cmdwin, and
          doesn't allow `vim.hl.on_yank()`.
Solution: When first opening the "more" window for spilled messages,
          move the message buffer to the more window.
          Restrict routing of typed commands to echo kinds.
          Ignore all events but WinLeave and TextYankPost.

runtime/lua/vim/_extui.lua

@@ -110,10 +110,8 @@ function M.enable(opts)
     end
   end
 
-  if vim.v.vim_did_enter == 1 then
+  ext.tab_check_wins()
-    ext.tab_check_wins()
+  check_opt('cmdheight', vim.o.cmdheight)
-    check_opt('cmdheight', vim.o.cmdheight)
-  end
 
   api.nvim_create_autocmd('OptionSet', {
     group = ext.augroup,

runtime/lua/vim/_extui/messages.lua

@@ -42,8 +42,8 @@ local M = {
 ---@param len integer Number of rows that should be removed.
 function M.box:start_timer(buf, len)
   self.timer = vim.defer_fn(function()
-    if self.count == 0 or not api.nvim_buf_is_valid(buf) then
+    if buf ~= ext.bufs.box or not api.nvim_buf_is_valid(buf) then
-      return -- Messages moved to split or buffer was closed.
+      return -- Messages moved to more or buffer was closed.
     end
     api.nvim_buf_set_lines(buf, 0, len, false, {})
     self.count = self.count - 1
@@ -168,6 +168,16 @@ local function set_virttext(type)
   end
 end
 
+---Move message buffer to more window.
+local function msg_to_more(tar)
+  api.nvim_win_set_buf(ext.wins[ext.tab].more, ext.bufs[tar])
+  api.nvim_buf_delete(ext.bufs.more, { force = true })
+  api.nvim_buf_set_name(ext.bufs[tar], 'vim._extui.more')
+  ext.bufs.more, ext.bufs[tar], M[tar].count = ext.bufs[tar], -1, 0
+  ext.tab_check_wins()
+  M.set_pos('more')
+end
+
 -- We need to keep track of the current message column to be able to
 -- append or overwrite messages for :echon or carriage returns.
 local col = 0
@@ -231,6 +241,7 @@ function M.show_msg(tar, content, replace_last, append, more)
           hl_group = chunk[3],
           undo_restore = false,
           invalidate = true,
+          priority = 1,
         })
       end
 
@@ -245,21 +256,20 @@ function M.show_msg(tar, content, replace_last, append, more)
   if tar == 'box' then
     api.nvim_win_set_width(ext.wins[ext.tab].box, width)
     local h = api.nvim_win_text_height(ext.wins[ext.tab].box, { start_row = start_row })
-    if h.all > (more and 1 or math.ceil(o.lines * 0.5)) then
+    if more and h.all > 1 then
-      api.nvim_buf_set_lines(ext.bufs.box, start_row, -1, false, {})
+      msg_to_more(tar)
       api.nvim_win_set_width(ext.wins[ext.tab].box, M.box.width)
-      M.msg_history_show({ { 'spill', content } }) -- show message in 'more' window
       return
     end
 
     M.set_pos('box')
+    M.box.width = width
     if restart then
       M.box.timer:stop()
       M.box.timer:set_repeat(4000)
       M.box.timer:again()
     else
       M.box:start_timer(ext.bufs.box, row - start_row + 1)
-      M.box.width = width
     end
   elseif tar == 'cmd' and dupe == 0 then
     fn.clearmatches(ext.wins[ext.tab].cmd) -- Clear matchparen highlights.
@@ -272,8 +282,8 @@ function M.show_msg(tar, content, replace_last, append, more)
     else
       local h = api.nvim_win_text_height(ext.wins[ext.tab].cmd, {})
       if more and h.all > ext.cmdheight then
-        api.nvim_buf_set_lines(ext.bufs.cmd, start_row, -1, false, {})
+        ext.cmd.highlighter:destroy()
-        M.msg_history_show({ { 'spill', content } }) -- show message in 'more' window
+        msg_to_more(tar)
         return
       end
 
@@ -302,7 +312,6 @@ function M.show_msg(tar, content, replace_last, append, more)
   end
 end
 
-local append_more = 0
 local replace_bufwrite = false
 --- Route the message to the appropriate sink.
 ---
@@ -329,7 +338,7 @@ function M.msg_show(kind, content, _, _, append)
     -- Verbose messages are sent too often to be meaningful in the cmdline:
     -- always route to box regardless of cfg.msg.pos.
     M.show_msg('box', content, false, append)
-  elseif append_more > 0 and ext.cfg.msg.pos == 'cmd' then
+  elseif ext.cfg.msg.pos == 'cmd' and api.nvim_get_current_win() == ext.wins[ext.tab].more then
     -- Append message to already open 'more' window.
     M.msg_history_show({ { 'spill', content } })
     api.nvim_command('norm! G')
@@ -351,8 +360,9 @@ function M.msg_show(kind, content, _, _, append)
       M.virt.last[M.virt.idx.search][1] = nil
     end
 
-    -- Messages sent as a result of a typed command should be routed to the more window.
+    -- Typed "inspection" messages should be routed to the more window.
-    local more = ext.cmd.level >= 0 or kind == 'list_cmd'
+    local typed_more = { 'echo', 'echomsg', 'lua_print' }
+    local more = kind == 'list_cmd' or (ext.cmd.level >= 0 and vim.tbl_contains(typed_more, kind))
     M.show_msg(tar, content, replace_bufwrite, append, more)
     -- Replace message for every second bufwrite message.
     replace_bufwrite = not replace_bufwrite and kind == 'bufwrite'
@@ -402,13 +412,13 @@ function M.msg_history_show(entries)
   end
 
   -- Appending messages while 'more' window is open.
-  if append_more == 0 then
+  local append_more = api.nvim_get_current_win() == ext.wins[ext.tab].more
+  if not append_more then
     api.nvim_buf_set_lines(ext.bufs.more, 0, -1, false, {})
   end
-  append_more = append_more + 1
 
   for i, entry in ipairs(entries) do
-    M.show_msg('more', entry[2], i == 1 and append_more < 2, false)
+    M.show_msg('more', entry[2], i == 1 and not append_more, false)
   end
 
   M.set_pos('more')
@@ -443,17 +453,16 @@ function M.set_pos(type)
       end
       -- It's actually closed one event iteration later so schedule in case it was open.
       vim.schedule(function()
-        api.nvim_create_autocmd('WinEnter', {
+        api.nvim_set_current_win(win)
+        api.nvim_create_autocmd('WinLeave', {
           once = true,
           callback = function()
             if api.nvim_win_is_valid(win) then
               api.nvim_win_set_config(win, { hide = true })
             end
-            append_more = 0
           end,
           desc = 'Hide inactive "more" window.',
         })
-        api.nvim_set_current_win(win)
       end)
     end
   end

runtime/lua/vim/_extui/shared.lua

@@ -88,7 +88,8 @@ function M.tab_check_wins()
         api.nvim_set_option_value('smoothscroll', true, { scope = 'local' })
         local ft = type == 'cmd' and 'cmdline' or ('msg' .. type)
         api.nvim_set_option_value('filetype', ft, { scope = 'local' })
-        api.nvim_set_option_value('eventignorewin', 'all', { scope = 'local' })
+        local ignore = 'all' .. (type == 'more' and ',-WinLeave,-TextYankPost' or '')
+        api.nvim_set_option_value('eventignorewin', ignore, { scope = 'local' })
       end)
     end
   end