vint: Syntastic: `unrecognized error format (crashed checker?)`?

I’m getting an error when I run :SyntasticCheck on VimL files. I have vim configured with only the options suggested for new users in Syntastic’s README:

let g:syntastic_vim_checkers = ['vint']

set statusline+=%#warningmsg#
set statusline+=%{SyntasticStatuslineFlag()}
set statusline+=%*

let g:syntastic_always_populate_loc_list = 1
let g:syntastic_auto_loc_list = 1
let g:syntastic_check_on_open = 1
let g:syntastic_check_on_wq = 0

Here’s the output for the Syntastic debug log:

syntastic: warning: checker vim/vint: unrecognized error format (crashed checker?)
syntastic: 255.519186: g:syntastic_version = '3.8.0-3 (Vim 800, Darwin, GUI)'
syntastic: 255.519360: &shell = '/bin/bash', &shellcmdflag = '-c', 
  &shellpipe = '2>&1 | tee', 
  &shellquote = '', 
  &shellredir = '>%s 2>&1', 
  &shelltemp = 1, 
  &shellxquote = '', 
  &autochdir = 0, 
  &shellxescape = ''
syntastic: 255.519927: UpdateErrors: vint
syntastic: 255.520186: CacheErrors: vint
syntastic: 255.520800: g:syntastic_aggregate_errors = 0
syntastic: 255.520984: getcwd() = '/Users/rlue'
syntastic: 255.521474: CacheErrors: Invoking checker: vim/vint
syntastic: 255.522067: SyntasticMake: called with options: 
  {'preprocess': 'vint', 
   'errorformat': '%f:%l:%c:%t: %m', 
   'makeprg': 'vint /Users/rlue/.vim/config/mappings.vim --json', 
   'returns': [0, 1]}
syntastic: 255.847839: system: command run in 0.325377s
syntastic: 255.848224: checker output: 
  ['Traceback (most recent call last):', 
   '  File "/usr/local/bin/vint", line 11, in <module>', 
   '    sys.exit(main())', 
   '  File "/usr/local/lib/python2.7/site-packages/vint/__init__.py", line 11, in main', 
   '    init_cli()', 
   '  File "/usr/local/lib/python2.7/site-packages/vint/bootstrap.py", line 22, in init_cli', 
   '    cli.start()', 
   '  File "/usr/local/lib/python2.7/site-packages/vint/linting/cli.py", line 26, in start', 
   '    config_dict = self._build_config_dict(env)',
   '  File "/usr/local/lib/python2.7/site-packages/vint/linting/cli.py", line 56, in _build_config_dict', 
   '    ConfigDefaultSource(env),', 
   '  File "/usr/local/lib/python2.7/site-packages/vint/linting/config/config_file_source.py", line 12, in __init__', 
   ' with config_file_path.open() as file_obj:', 
   '  File "/usr/local/lib/python2.7/site-packages/pathlib.py", line 1077, in open', 
   '    return io.open(str(self), mode, buffering, encoding, errors, newline)', 
   'LookupError: unknown encoding: ', '']
syntastic: warning: checker vim/vint: unrecognized error format (crashed checker?)
syntastic: 255.849312: preprocess: []
syntastic: 255.849533: raw loclist: []
syntastic: 255.849727: getLocList: checker vim/vint returned 1
syntastic: 255.849863: vim/vint raw: []
syntastic: 255.850016: quiet_messages filter: {}
syntastic: 255.850130: getLocList: checker vim/vint run in 0.328544s
syntastic: 255.850399: aggregated: {'_sorted': 0, '_name': '', '_owner': 2, '_columns': 1, '_rawLoclist': []}

It appears this problem has cropped up with other linters, as well. Maybe a null value is being passed as an argument to io.open?

File "/usr/local/lib/python2.7/site-packages/pathlib.py", line 1077, in open
    return io.open(str(self), mode, buffering, encoding, errors, newline)
LookupError: unknown encoding: 

I’d dig through the traceback in more detail, but I don’t know python at all. :\