ruby bubble sort

bubblesort.rb

def bubble_sort(list)
  return list if list.size <= 1
  loop do
    sorted = true
    index_right = 2
    0.upto(list.size-index_right) do |i|
      if list[i] > list[i+1]
        list[i], list[i+1] = list[i+1], list[i]
        sorted = false
      end
    end
    index_right += 1 # the right of index_right are already sorted
    break if sorted # no swap
  end

  list
end

array = [6, 5, 3, 1, 8, 7, 2, 4]
p bubble_sort(array)