Vim syntax highlighting lost on single file

Question

I have a strange thing happening on a single file. When I open the file under it's original name, the highlighting is lost (":syntax on" does nothing). But if I cp that file with another name and open it, the syntax highlighting returns. If I mv that copy back to the original file name, the highlighting is gone again.

I can't show you images (as my rep is not high enough), but I assure you if I could, you could clearly see that file a.js has no highlighting while a_copy.js does.

Answer 1

You provide very little information about your environment and configuration, so I can just help you help yourself.

Compare the following options for the two different JavaScript files:

:verbose setlocal syntax? filetype?

Then check the list of :autocmd for any pattern that might target the problematic JavaScript file. Do you use a local vimrc plugin? It might affect this, too.

If all that doesn't provide a clue, capture the sequence of commands with

:set verbose=20 | edit a.js

and watch out for commands that affect 'syntax'.

Answer 2

Try deleting any saved views (i.e. from mkview). I often have this problem if I didn't cleanly exit all my vims when I logout/shutdown. If you've set something like

au BufWinLeave ?* mkview

in your .vimrc as many do, you'll automatically have these views. As mentioned in the accepted answer, you can find where this file is by using:

:verbose setlocal syntax? filetype?

Answer 3

Apart from having syntax on in .vimrc, you may also need to delete a view that has been stored for this particular file in the .vim/view dir:

$ cd ~/.vim/view

# list all files looking for your particular file
$ ls -lt # | head -10 
...

# delete that file
$ rm ...

Note that files in the view/ folder will have their full path on the filesystem, with the / replaced by =+.

Answer 4

This is an old question but since this has happened to me several times I thought I might as well share my solution.

As suggested, I compared the original and the copy (with colors) by:

:verbose setlocal syntax? filetype?

Original

  syntax=
        Last set from /usr/share/vim/vim80/syntax/syntax.vim
  filetype=
        Last set from ~/.vim/view/~=+Thesis=+thesis.tex=

Copy

  syntax=tex
        Last set from /usr/share/vim/vim80/syntax/syntax.vim
  filetype=tex
        Last set from /usr/share/vim/vim80/autoload/dist/ft.vim`

The solution to this for me was to :set filetype=tex (or whatever file extension you're working with.) I haven't been able to track down exactly why this happens but it seems to me that it happens after deleting .swp files.