How to prevent syntastic from creating a directory for every vim instance?

Question

When using the syntastic plugin with vim, I see a new /tmp/vXXXXXXX directory every time I open a new vim instance. When the syntastic plugin gets disabled, no such directories are created.

When I ran inotify, I found that a numeric file is created in that directory every time I save a file. Is it possible to make syntastic (or vim) create a temporary directory on demand? Failing on that, can I make it use a single directory instead? For example, /tmp/vim-syntastic/vXXXXXXX/?

Answer 1

According to the developer, syntastic does not create temporary directories by itself, that is handled by vim. Looking a bit further, I found that vim uses $TMPDIR to set a temporary directory. If the directory is unwritable, then it gets ignored.

So, as a solution, the following lines set the temporary directory to /tmp/vim-USERNAME, and then create it (ignoring errors that normally occur when the directory exists):

" Keep all vim-related temp files in a single directory
let $TMPDIR = '/tmp/vim-' . $USER
silent! call mkdir($TMPDIR, '', 0700)

Now, I do not have a lot of /tmp/vXXXXXX/ directories anymore. Instead, they appear in /tmp/vim-peter/vXXXXXX/ which is great.

Answer 2

If you look in the syntastic helpfiles, you'll see that syntastic uses a 'tail' file for storing the output of a given make program. You can override the default tail for a given filetype and subchecker by adding the following to your vimrc:

let g:syntastic_<filetype>_<subchecker>_tail = "> /tmp/vim-syntastic/your-file-here"

So for example if you wanted mri to output to /tmp/vim-syntastic/ruby-mri, you would write:

let g:syntastic_ruby_mri_tail = "> /tmp/vim-syntastic/ruby-mri"

See :help syntastic-config-makeprg for more info. Here's a direct link on git. As far as I know there's no built-in way to set the default directory for all syntastic output, unfortunately.

Edit: Lekenstein found another solution, which he posted in the linked Github issue.

let $TMPDIR = '/tmp/vim-' . $USER
silent! call mkdir($TMPDIR, '', 0700)

This will make a special directory for all vim-related temporary files. That means it will also affect temporary files not related to syntastic.