Ability to use left_joins with ActiveRecord

extensions.rb

module ActiveRecord
  
  module QueryMethods
    #keeping track of left joins sent
    attr_accessor :left_joins_values

    #photocopy of joins except for the variable that records left_joins separate from the joins
    def left_joins(*args)
      return self if args.compact.blank?

      relation = clone

      args.flatten!
      relation.left_joins_values ||= []
      relation.left_joins_values += args

      relation
    end

    alias_method :original_build_joins, :build_joins
    def build_joins(manager, joins)
      #build original
      original_build_joins(manager, joins)

      #add left joins .. considering only the ones with associations
      association_joins, other_joins = (left_joins_values||[]).partition{|join| join.is_a?(Hash) or join.is_a?(Symbol) or join.is_a?(Array) }
      
      #for any other kind of join, use it the same way
      original_build_joins(manager, other_joins) unless other_joins.empty?
  
      #association ones .. use join_type OuterJoin to create the associative join
      unless association_joins.empty?
        join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, association_joins, [])
        join_dependency.join_associations.each do |association|
          association.join_type = Arel::OuterJoin
          association.join_to(manager)
        end
      end

      manager
    end

  end
end