class Bundler::Index

def search_by_dependency(dependency, base = nil)
  @cache[base || false] ||= {}
  @cache[base || false][dependency] ||= begin
    specs = specs_by_name(dependency.name) + (base || [])
    found = specs.select do |spec|
      if base # allow all platforms when searching from a lockfile
        dependency.matches_spec?(spec)
      else
        dependency.matches_spec?(spec) && Gem::Platform.match(spec.platform)
      end
    end
    wants_prerelease = dependency.requirement.prerelease?
    only_prerelease  = specs.all? {|spec| spec.version.prerelease? }
    unless wants_prerelease || only_prerelease
      found.reject! { |spec| spec.version.prerelease? }
    end
    found.sort_by {|s| [s.version, s.platform.to_s == 'ruby' ? "\0" : s.platform.to_s] }
  end
end