Uncaught TypeError: Array.prototype.indexOf called on null or undefined

[kokujin]

[Enter steps to reproduce:]

1. ...
2. ...

Atom: 1.14.0 x64
Electron: 1.3.13
OS: Mac OS X 10.11.6
Thrown From: project-ring package 0.39.0

Stack Trace

Uncaught TypeError: Array.prototype.indexOf called on null or undefined

At /Users/saina/.atom/packages/project-ring/lib/project-ring.coffee:170

TypeError: Array.prototype.indexOf called on null or undefined
    at indexOf (native)
    at /packages/project-ring/lib/project-ring.coffee:170:11)
    at emitTwo (events.js:106:13)
    at FSWatcher.emit (events.js:191:7)
    at FSEvent.FSWatcher._handle.onchange (fs.js:1422:12)

Commands

     -1:48.9.0 core:move-down (input.hidden-input)
     -1:48.5.0 core:move-right (input.hidden-input)
     -1:47.7.0 core:delete (input.hidden-input)
     -1:46.3.0 core:save (input.hidden-input)
  2x -1:14.8.0 core:move-left (input.hidden-input)
     -1:13.6.0 core:delete (input.hidden-input)
     -1:11.8.0 core:save (input.hidden-input)
 24x -1:03.3.0 core:delete (input.hidden-input)
  7x -0:58.2.0 core:move-down (input.hidden-input)
     -0:54.1.0 core:move-right (input.hidden-input)
     -0:53.2.0 core:move-up (input.hidden-input)
 44x -0:52.5.0 core:move-right (input.hidden-input)
 24x -0:48.6.0 core:delete (input.hidden-input)
 35x -0:45.8.0 core:move-right (input.hidden-input)
 23x -0:42.8.0 core:delete (input.hidden-input)
     -0:38.5.0 core:save (input.hidden-input)

Non-Core Packages

aligner 0.22.3 
atom-beautify 0.29.17 
atom-dark-fusion-syntax 2.0.3 
atom-dark-ui-slim 0.47.1 
atom-easy-jsdoc 4.10.0 
atom-gooey-syntax 0.2.1 
atom-jinja2 0.6.0 
atom-jshint 2.0.0 
atom-soda-dark-ui 1.1.0 
atom-ternjs 0.17.0 
autoclose-html 0.23.0 
autocomplete-paths 1.0.5 
color-picker 2.2.5 
copy-path 0.4.0 
dark-flat-ui 1.2.4 
docblockr 0.9.1 
emmet-simplified 2.5.0 
file-icons 2.0.15 
flatland-dark 0.2.2 
fold-search-results 1.0.5 
foldername-tabs 0.2.4 
formatter-jsbeautify 1.0.2 
git-control 0.8.2 
git-diff-details 1.4.0 
hecs-dark-ui 0.1.4 
highlight-line 0.12.0 
highlight-selected 0.12.0 
htmlhint 1.1.4 
isotope-ui 2.7.1 
jscs-fixer 1.3.0 
jsdoc-generator 0.2.3 
jsformat 0.9.3 
lanai-dark-ui 0.5.0 
language-ini 1.17.0 
language-riot-tag 0.2.2 
linter 1.11.21 
linter-htmlhint 1.3.1 
linter-js-standard 3.8.0 
minimap 4.26.8 
minimap-color-highlight 4.1.4 
minimap-git-diff 4.3.1 
newton-dark-ui 1.1.0 
outlander-syntax 2.0.0 
outlander-ui 1.3.1 
pigments 0.39.0 
project-ring 0.39.0 
seti-icons 1.3.4 
seti-ui 1.6.0 
sort-lines 0.14.0 
speckjs 1.0.0 
split-diff 1.1.1 
symbols-tree-view 0.13.2 
tabs-to-spaces 1.0.3 
todo-show 1.9.0 
tool-bar 1.0.1 
tree-view-big-files 0.4.1 
tree-view-git-branch 0.1.2 
tree-view-git-status 1.3.0