change_reason

# File lib/bundler/definition.rb, line 548
    def change_reason
      if unlocking?
        unlock_reason = @unlock.reject {|_k, v| Array(v).empty? }.map do |k, v|
          if v == true
            k.to_s
          else
            v = Array(v)
            "#{k}: (#{v.join(", ")})"
          end
        end.join(", ")
        return "bundler is unlocking #{unlock_reason}"
      end
      [
        [@source_changes, "the list of sources changed"],
        [@dependency_changes, "the dependencies in your gemfile changed"],
        [@new_platform, "you added a new platform to your gemfile"],
        [@path_changes, "the gemspecs for path gems changed"],
        [@local_changes, "the gemspecs for git local gems changed"],
        [@locked_specs_incomplete_for_platform, "the lockfile does not have all gems needed for the current platform"],
      ].select(&:first).map(&:last).join(", ")
    end