Add deep_diff method to Hash to more easily see locations of differences between crazy nested hashes.

gistfile1.rb

class DiffObject
  attr :left, :right
  def initialize(left, right)
    @left = left
    @right = right
  end
end

class Hash
  # a_hash.deep_diff(b_hash) returns:
  # key_with_different_value => DiffObject, key_with_hash_value_in_both => {nested_key_with_different_value => DiffObject}
  def deep_diff(other_hash)
    diff = {}

    keys.each do |key|
      if (value = self[key]) == (other_value = other_hash[key])
        next
      elsif (value.is_a?(Hash) && other_value.is_a?(Hash)) || (value.is_a?(Array) && other_value.is_a?(Array))
        diff[key] = value.deep_diff(other_value)
      else
        diff[key] = DiffObject.new(value, other_value)
      end
    end

    (other_hash.keys - keys).each do |key|
      diff[key] = DiffObject.new(nil, other_hash[key])
    end

    diff
  end
end

class Array
  #not really good about ordering
  def deep_diff(other_array)
    if self.length != other_array.length
      DiffObject.new(self, other_array)
    elsif (self.all?{|v| v.is_a?(Hash)} && other_array.all?{|v| v.is_a?(Hash)}) || (self.all?{|v| v.is_a?(Array)} && other_array.all?{|v| v.is_a?(Array)})
      self.each_with_index.map{|value,i| value.deep_diff(other_array[i])}
    else
      DiffObject.new(self, other_array)
    end
  end
end