Refactor a bit

lua/cmp/config/default.lua

@@ -5,7 +5,8 @@ local WIDE_HEIGHT = 40
 
 ---@return cmp.ConfigSchema
 return function()
-  return {
+  ---@type cmp.ConfigSchema
+  local config = {
     enabled = function()
       local disabled = false
       disabled = disabled or (vim.api.nvim_buf_get_option(0, 'buftype') == 'prompt')
@@ -17,7 +18,7 @@ return function()
     performance = {
       debounce = 60,
       throttle = 30,
-      fetching_timeout = 200,
+      fetching_timeout = 500,
     },
 
     preselect = types.cmp.PreselectMode.Item,
@@ -25,7 +26,7 @@ return function()
     mapping = {},
 
     snippet = {
-      expand = function()
+      expand = function(_)
         error('snippet engine is not configured.')
       end,
     },
@@ -105,4 +106,5 @@ return function()
       },
     },
   }
+  return config
 end

lua/cmp/core.lua

@@ -369,6 +369,7 @@ core.confirm = function(self, e, option, callback)
     feedkeys.call(table.concat(keys, ''), 'in')
   end)
   feedkeys.call('', 'n', function()
+    -- Restore the line at the time of request.
     local ctx = context.new()
     if api.is_cmdline_mode() then
       local keys = {}
@@ -377,13 +378,12 @@ core.confirm = function(self, e, option, callback)
       feedkeys.call(table.concat(keys, ''), 'in')
     else
       vim.cmd([[silent! undojoin]])
-      vim.api.nvim_buf_set_text(0, ctx.cursor.row - 1, e:get_offset() - 1, ctx.cursor.row - 1, ctx.cursor.col - 1, {
-        string.sub(e.context.cursor_before_line, e:get_offset()),
-      })
+      vim.api.nvim_set_current_line(e.context.cursor_line)
       vim.api.nvim_win_set_cursor(0, { e.context.cursor.row, e.context.cursor.col - 1 })
     end
   end)
   feedkeys.call('', 'n', function()
+    -- Apply additionalTextEdits.
     local ctx = context.new()
     if #(misc.safe(e:get_completion_item().additionalTextEdits) or {}) == 0 then
       e:resolve(function()