demo.rb

require 'rubygems'
require 'chef'

# good!
x = {
  :first_level => {
    :one => 1
  }
}

y = {
  :first_level => {
    :two => 2
  }
}

p Chef::Mixin::DeepMerge.merge(x, y)

# bad - not deep enough!
x = {
  :first_level => {
    :second_level => {
      :one => 1
    }
  }
}

y = {
  :first_level => {
    :second_level => {
      :two => 2
    }
  }
}

p Chef::Mixin::DeepMerge.merge(x, y)

gistfile2.txt

{"first_level"=>{"two"=>2, "one"=>1}}
{"first_level"=>{"second_level"=>{"two"=>2}}}