check_for_corrupt_lockfile

# File lib/bundler/installer/parallel_installer.rb, line 112
    def check_for_corrupt_lockfile
      missing_dependencies = @specs.map do |s|
        [
          s,
          s.missing_lockfile_dependencies(@specs.map(&:name)),
        ]
      end.reject { |a| a.last.empty? }
      return if missing_dependencies.empty?

      warning = []
      warning << "Your lockfile was created by an old Bundler that left some things out."
      if @size != 1
        warning << "Because of the missing DEPENDENCIES, we can only install gems one at a time, instead of installing #{@size} at a time."
        @size = 1
      end
      warning << "You can fix this by adding the missing gems to your Gemfile, running bundle install, and then removing the gems from your Gemfile."
      warning << "The missing gems are:"

      missing_dependencies.each do |spec, missing|
        warning << "* #{missing.map(&:name).join(", ")} depended upon by #{spec.name}"
      end

      Bundler.ui.warn(warning.join("\n"))
    end