This probably comes from linecache gem version 0.45 , which was released yesterday. A return to 0.43 will show you this. I'm not sure if they intentionally violated support with Ruby 1.8.7 or not.
This is a ruby-debug-base dependency.
Add something like the following to your Gemfile .
group :development, :test, :cucumber do gem "linecache", "0.43" gem "ruby-debug-base", "0.10.4.0" gem "ruby-debug", "0.10.4" end
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