Warbler::Traits::Bundler packages gems into a jar.

Running require "bundler/setup" inside the jar will try to Dir.chdir into these directories in order to evaluate gemspecs in their respective local path context.

This fails ... and as far as I understand basically renders Warbler::Traits::Bundler useless?

pry(main)> File.directory?('file:/path/to/some.jar!/gems')
=> true
pry(main)> Dir.chdir('file:/path/to/some.jar!/gems')
Errno::ENOTDIR: Not a directory - file:/path/to/some.jar!/gems
from org/jruby/RubyDir.java:458:in `chdir'

Here's a related issue on bundler: rubygems/bundler#1865 (comment)