# File lib/bundler/definition.rb, line 332
    def ensure_equivalent_gemfile_and_lockfile(explicit_flag = false)
      msg = "You are trying to install in deployment mode after changing\n" \
            "your Gemfile. Run `bundle install` elsewhere and add the\n" \
            "updated Gemfile.lock to version control."

      unless explicit_flag
        msg += "\n\nIf this is a development machine, remove the Gemfile " \
               "freeze \nby running `bundle install --no-deployment`."
      end

      added =   []
      deleted = []
      changed = []

      gemfile_sources = sources.lock_sources
      if @locked_sources != gemfile_sources
        new_sources = gemfile_sources - @locked_sources
        deleted_sources = @locked_sources - gemfile_sources

        if new_sources.any?
          added.concat new_sources.map { |source| "* source: #{source}" }
        end

        if deleted_sources.any?
          deleted.concat deleted_sources.map { |source| "* source: #{source}" }
        end
      end

      new_deps = @dependencies - @locked_deps
      deleted_deps = @locked_deps - @dependencies

      if new_deps.any?
        added.concat new_deps.map { |d| "* #{pretty_dep(d)}" }
      end

      if deleted_deps.any?
        deleted.concat deleted_deps.map { |d| "* #{pretty_dep(d)}" }
      end

      both_sources = Hash.new { |h,k| h[k] = [] }
      @dependencies.each { |d| both_sources[d.name][0] = d }
      @locked_deps.each  { |d| both_sources[d.name][1] = d.source }

      both_sources.each do |name, (dep, lock_source)|
        if (dep.nil? && !lock_source.nil?) || (!dep.nil? && !lock_source.nil? && !lock_source.can_lock?(dep))
          gemfile_source_name = (dep && dep.source) || 'no specified source'
          lockfile_source_name = lock_source || 'no specified source'
          changed << "* #{name} from `#{gemfile_source_name}` to `#{lockfile_source_name}`"
        end
      end

      msg << "\n\nYou have added to the Gemfile:\n"     << added.join("\n") if added.any?
      msg << "\n\nYou have deleted from the Gemfile:\n" << deleted.join("\n") if deleted.any?
      msg << "\n\nYou have changed in the Gemfile:\n"   << changed.join("\n") if changed.any?
      msg << "\n"

      raise ProductionError, msg if added.any? || deleted.any? || changed.any?
    end