fix(extui): use visible to determine active "more" (#34327)

Problem:  Current window is checked to determine whether "more" window
          is open. Making it the current window is scheduled in case the
          cmdwin is open so this can be too late.
          "cmdline_hide" may be emitted when the topline is
          temporarily invalid (after incsearch->restore_viewstate()).
Solution: Use the window visibility to determine an active "more"
          window instead.
          Don't nvim__redraw->flush the "cmdline_hide" event (a normal
          will already happen).

runtime/lua/vim/_extui.lua

@@ -49,7 +49,7 @@ local function ui_callback(event, ...)
   ext.tab_check_wins()
   handler(...)
   api.nvim__redraw({
-    flush = true,
+    flush = handler ~= ext.cmd.cmdline_hide or nil,
     cursor = handler == ext.cmd[event] and true or nil,
     win = handler == ext.cmd[event] and ext.wins.cmd or nil,
   })

runtime/lua/vim/_extui/cmdline.lua

@@ -99,6 +99,7 @@ function M.cmdline_pos(pos)
     curpos[1], curpos[2] = M.row + 1, promptlen + pos
     -- Add matchparen highlighting to non-prompt part of cmdline.
     if pos > 0 and fn.exists('#matchparen') then
+      api.nvim_win_set_cursor(ext.wins.cmd, { curpos[1], curpos[2] - 1 })
       vim._with({ win = ext.wins.cmd, wo = { eventignorewin = '' } }, function()
         api.nvim_exec_autocmds('CursorMoved', {})
       end)

runtime/lua/vim/_extui/messages.lua

@@ -36,6 +36,15 @@ local M = {
   },
 }
 
+function M.box:close()
+  self.width, M.virt.msg = 1, { {}, {} }
+  M.prev_msg = ext.cfg.msg.pos == 'box' and '' or M.prev_msg
+  api.nvim_buf_clear_namespace(ext.bufs.box, -1, 0, -1)
+  if api.nvim_win_is_valid(ext.wins.box) then
+    api.nvim_win_set_config(ext.wins.box, { hide = true })
+  end
+end
+
 --- Start a timer whose callback will remove the message from the message window.
 ---
 ---@param buf integer Buffer the message was written to.
@@ -51,12 +60,7 @@ function M.box:start_timer(buf, len)
     if self.count > 0 then
       M.set_pos('box')
     else
-      self.width = 1
+      self:close()
-      M.prev_msg = ext.cfg.msg.pos == 'box' and '' or M.prev_msg
-      api.nvim_buf_clear_namespace(ext.bufs.box, -1, 0, -1)
-      if api.nvim_win_is_valid(ext.wins.box) then
-        api.nvim_win_set_config(ext.wins.box, { hide = true })
-      end
     end
   end, ext.cfg.msg.box.timeout)
 end
@@ -257,7 +261,7 @@ function M.show_msg(tar, content, replace_last, append, more)
     local h = api.nvim_win_text_height(ext.wins.box, { start_row = start_row })
     if more and h.all > 1 then
       msg_to_more(tar)
-      api.nvim_win_set_width(ext.wins.box, M.box.width)
+      M.box:close()
       return
     end
 
@@ -337,7 +341,7 @@ 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 ext.cfg.msg.pos == 'cmd' and api.nvim_get_current_win() == ext.wins.more then
+  elseif ext.cfg.msg.pos == 'cmd' and not api.nvim_win_get_config(ext.wins.more).hide then
     -- Append message to already open 'more' window.
     M.msg_history_show({ { 'spill', content } })
     api.nvim_command('norm! G')
@@ -411,13 +415,13 @@ function M.msg_history_show(entries)
   end
 
   -- Appending messages while 'more' window is open.
-  local append_more = api.nvim_get_current_win() == ext.wins.more
+  local clear = entries[1][1] ~= 'spill' or api.nvim_win_get_config(ext.wins.more).hide == true
-  if not append_more then
+  if clear then
     api.nvim_buf_set_lines(ext.bufs.more, 0, -1, false, {})
   end
 
   for i, entry in ipairs(entries) do
-    M.show_msg('more', entry[2], i == 1 and not append_more, false)
+    M.show_msg('more', entry[2], i == 1 and clear, false)
   end
 
   M.set_pos('more')
@@ -439,18 +443,19 @@ function M.set_pos(type)
       row = win == ext.wins.box and 0 or 1,
       col = 10000,
     }
-    api.nvim_win_set_config(win, config)
+
     if type == 'box' then
       -- Ensure last line is visible and first line is at top of window.
       local row = (texth.all > height and texth.end_row or 0) + 1
       api.nvim_win_set_cursor(ext.wins.box, { row, 0 })
-    elseif type == 'more' and api.nvim_get_current_win() ~= win then
+    elseif type == 'more' and api.nvim_win_get_config(win).hide then
       -- Cannot leave the cmdwin to enter the "more" window, so close it.
       -- NOTE: regression w.r.t. the message grid, which allowed this. Resolving
       -- that would require somehow bypassing textlock for the "more" window.
       if fn.getcmdwintype() ~= '' then
         api.nvim_command('quit')
       end
+
       -- It's actually closed one event iteration later so schedule in case it was open.
       vim.schedule(function()
         api.nvim_set_current_win(win)
@@ -471,6 +476,7 @@ function M.set_pos(type)
         })
       end)
     end
+    api.nvim_win_set_config(win, config)
   end
 
   for t, win in pairs(ext.wins) do