[DRE-maint] Bug#794139: FTBFS: test_: converting CoffeeScript should produce JS. (TestCoffeeScript) fails

[Chris West (Faux)]

Source: jekyll
Version: 2.2.0+dfsg-2
Severity: serious
Tags: sid stretch
Justification: fails to build from source
User: reproducible-builds at lists.alioth.debian.org
Usertags: ftbfs

Dear Maintainer,

The package fails to build:

Failure: test_: converting CoffeeScript should produce JS. (TestCoffeeScript)
[..]
diff:
  (function() {
- 
    $(function() {
      var cube, cubes, list, num, square;
      list = [1, 2, 3, 4, 5];
      square = function(x) {
        return x * x;
      };
      cube = function(x) {
        return square(x) * x;
      };
      cubes = (function() {
?       var _i, _len, _results;
?                              
?       _results = [];
?                     
?       for (_i = 0, _len = list.length; _i < _len; _i++) {
?                                                          
?         num = list[_i];
?         _results.push(math.cube(num));
?                                       
        }
?       return _results;
?                       
      })();
      if (typeof elvis !== "undefined" && elvis !== null) {
        return alert("I knew it!");
      }
    });
  
  }).call(this);
  
? Encoding: UTF-8    
?            S  ASCII

Maybe the coffeescript compiler has changed?

Full build log:
https://reproducible.debian.net/rb-pkg/unstable/amd64/jekyll.html

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.19.0-23-generic (SMP w/8 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)