class Bundler::Repository

def prune(dependencies, sources)
  sources.each do |s|
    s.repository = self
    s.local = true
  end
  sources = only_local(sources)
  bundle = Resolver.resolve(dependencies, [@cache] + sources)
  @cache.gems.each do |name, specs|
    specs.each do |spec|
      unless bundle.any? { |s| s.name == spec.name && s.version == spec.version }
        Bundler.logger.info "Pruning #{spec.name} (#{spec.version}) from the cache"
        FileUtils.rm @path.join("cache", "#{spec.full_name}.gem")
      end
    end
  end
end