module ActiveRecord::AttributeMethods::Read

def _read_attribute(attr_name, &block) # :nodoc:

:nodoc:
breaking compatibility with the read_attribute API
This method exists to avoid the expensive primary_key check internally, without 
def _read_attribute(attr_name, &block) # :nodoc:
  @attributes.fetch_value(attr_name, &block)
end

def read_attribute(attr_name, &block)

casting behavior, see the types under ActiveModel::Type.)
to Date.new(2004, 12, 12). (For information about specific type
has been type cast. For example, a date attribute will cast "2004-12-12"
Returns the value of the attribute identified by +attr_name+ after it 
def read_attribute(attr_name, &block)
  name = attr_name.to_s
  name = self.class.attribute_aliases[name] || name
  return @attributes.fetch_value(name, &block) unless name == "id" && @primary_key
  if self.class.composite_primary_key?
    @attributes.fetch_value("id", &block)
  else
    if @primary_key != "id"
      ActiveRecord.deprecator.warn(<<-MSG.squish)
        Using read_attribute(:id) to read the primary key value is deprecated.
        Use #id instead.
      MSG
    end
    @attributes.fetch_value(@primary_key, &block)
  end
end