fix: return third result in file-opening functions

compat53/module.lua

@@ -848,7 +848,7 @@ if lua_version < "5.3" then
  end
 
  function M.io.open(...)
- local fd, err = io_open(...)
+ local fd, err, code = io_open(...)
  if fd and debug_setmetatable then
  if not compat_file_meta_loaded then
  local file_meta = gmt(fd)
@@ -857,11 +857,15 @@ if lua_version < "5.3" then
  debug_setmetatable(fd, compat_file_meta)
  end
 
- return fd, err
+ if fd then
+ return fd
+ else
+ return fd, err, code
+ end
  end
 
  function M.io.popen(...)
- local fd, err = io_popen(...)
+ local fd, err, code = io_popen(...)
  if fd and debug_setmetatable then
  if not compat_file_meta_loaded then
  local file_meta = gmt(fd)
@@ -870,11 +874,15 @@ if lua_version < "5.3" then
  debug_setmetatable(fd, compat_file_meta)
  end
 
- return fd, err
+ if fd then
+ return fd
+ else
+ return fd, err, code
+ end
  end
 
  function M.io.tmpfile(...)
- local fd, err = io_tmpfile(...)
+ local fd, err, code = io_tmpfile(...)
  if fd and debug_setmetatable then
  if not compat_file_meta_loaded then
  local file_meta = gmt(fd)
@@ -883,7 +891,11 @@ if lua_version < "5.3" then
  debug_setmetatable(fd, compat_file_meta)
  end
 
- return fd, err
+ if fd then
+ return fd
+ else
+ return fd, err, code
+ end
  end
  end