node.js - Grunt/bower Bourbon Upgrade breaks font-face mixin -

i upgraded grunt/angular project

"bourbon": "3.2.0", "neat": "1.5.0", 

to

"bourbon": "~4.2.3", "neat": "~1.7.2", 

(from bower.json)

over course of upgrade bourbon file structure changed from:

bower_components/bourbon/dist/bourbon' 

to:

bower_components/bourbon/app/assets/stylesheets/bourbon' 

this have handle on, or @ least think do.

now, whenever try build grunt, following sass issue:

running "sass:dist" (sass) task warning: [my_app_path]/bower_components/bourbon/app/assets/stylesheets/helpers/font-source-declaration:22: error: error reading values after eot 

the issue comes in first entry in formats-map here:

@function font-source-declaration(   $font-family,   $file-path,   $asset-pipeline,   $file-formats,   $font-url) {    $src: ();    $formats-map: (     eot:  "#{$file-path}.eot?#iefix" format("embedded-opentype"),     woff2: "#{$file-path}.woff2" format("woff2"),     woff:  "#{$file-path}.woff" format("woff"),     ttf:  "#{$file-path}.ttf" format("truetype"),     svg:  "#{$file-path}.svg##{$font-family}" format("svg")   );  

first off, how verify $file-path bourbon trying reference? i've spidered through other .scss files, , don't see hard definition or path being programmatically determined (i think might because don't know look.

am missing dependent library?

on ruby side have sass (3.4.16) scss_lint (0.40.1)

scss_lint upgraded scss-lint 0.26.2 (the package name changed hypen underscore on time)

so, problem application using old version of grunt-sass.

i upgraded 0.14.0 ^1.0.0, , works smoothly.