fix(base): update error_msg correctly

lua/pathlib/base.lua

@@ -513,6 +513,9 @@ end
 ---@param recursive boolean # if true, creates parent directories as well
 ---@return boolean? success
 function Path:mkdir(mode, recursive)
+  if self:is_dir() then
+    return true
+  end
   if recursive then
     local parent = self:parent()
     if parent and not parent:is_dir() then

lua/pathlib/utils/nuv.lua

@@ -2,15 +2,6 @@ local nio = require("nio")
 
 local M = {}
 
-local function luv_err_msg(self, func, ...)
-  local result = { func(...) }
-  if not result[1] then
-    self.error_msg = result[2]
-    return nil
-  end
-  return unpack(result)
-end
-
 if not nio.current_task then
   nio.current_task = function()
     return require("nio.tasks").current_task()
@@ -25,16 +16,25 @@ function M.generate_nuv(self)
         if nio.current_task() or type(select(-1, ...)) == "function" then
           -- is inside async task or is passed a `callback`
           local result = { nio.uv[key](...) }
+          -- result[1]: err_msg or nil
+          -- result[2, ...]: return values
           if result[1] then
             self.error_msg = result[1]
           end
           return unpack(result, 2)
         end
+        local result
         if key == "fs_opendir" then
           local args = { ... }
-          return luv_err_msg(self, vim.loop.fs_opendir, args[1], args[3], args[2])
+          result = { vim.loop.fs_opendir(args[1], args[3], args[2]) }
+        else
+          result = { vim.loop[key](...) }
+        end
+        if not result[1] then
+          self.error_msg = result[2]
+          return nil
         end
-        return luv_err_msg(self, vim.loop[key], ...)
+        return unpack(result)
       end
     end,
   })