patch 8.1.1639: changing an autoload name into a file name is inefficient commit https://github.com/vim/vim/commit/28fc247f8d94a1cfabbcf2691ca942bde96f6d2f Author: Bram Moolenaar <Bram@vim.org> Date: Fri Jul 5 22:14:16 2019 +0200 patch 8.1.1639: changing an autoload name into a file name is inefficient Problem: Changing an autoload name into a script file name is inefficient. Solution: Remember the last replaced #. (Ozaki Kiichi, closes https://github.com/vim/vim/issues/4618)

" Vim filetype plugin
" Language:	Dockerfile
" Maintainer:   Honza Pokorny <http://honza.ca>
" Last Change:	2014 Aug 29

" Only do this when not done yet for this buffer
if exists("b:did_ftplugin")
  finish
endif

" Don't load another plugin for this buffer
let b:did_ftplugin = 1

let b:undo_ftplugin = "setl commentstring<"

setlocal commentstring=#\ %s