fix(api): vim.filetype.get_option()

- Fix a bug in the cache
- Set some buffer options on the dummy buffer

runtime/lua/vim/filetype/options.lua

@@ -3,14 +3,22 @@ local api = vim.api
 local M = {}
 
 local function get_ftplugin_runtime(filetype)
- return api.nvim__get_runtime({
+ local files = api.nvim__get_runtime({
  string.format('ftplugin/%s.vim', filetype),
  string.format('ftplugin/%s_*.vim', filetype),
  string.format('ftplugin/%s/*.vim', filetype),
  string.format('ftplugin/%s.lua', filetype),
  string.format('ftplugin/%s_*.lua', filetype),
  string.format('ftplugin/%s/*.lua', filetype),
  }, true, {}) --[[@as string[] ]]
+
+ local r = {} ---@type string[]
+ for _, f in ipairs(files) do
+ if not vim.startswith(f, vim.env.VIMRUNTIME) then
+ r[#r + 1] = f
+ end
+ end
+ return r
 end
 
 -- Keep track of ftplugin files

src/nvim/api/options.c

@@ -104,6 +104,10 @@ static buf_T *do_ft_buf(char *filetype, aco_save_T *aco, Error *err)
 
  // Allocate a buffer without putting it in the buffer list.
  buf_T *ftbuf = buflist_new(NULL, NULL, 1, BLN_DUMMY);
+ set_option_value("bufhidden", 0L, "hide", OPT_LOCAL);
+ set_option_value("buftype", 0L, "nofile", OPT_LOCAL);
+ set_option_value("swapfile", 0L, NULL, OPT_LOCAL);
+ set_option_value("modeline", 0L, NULL, OPT_LOCAL); // 'nomodeline'
  if (ftbuf == NULL) {
  api_set_error(err, kErrorTypeException, "Could not create internal buffer");
  return NULL;