ruby on rails - mismatch setting and preloading of polymorphic association for STI models -

github issue link

let see have polymorphic table

class db::document < activerecord::base   # documentable_type, documentable_id   belongs_to :documentable, polymorphic: true end  class db::ticket < activerecord::base   has_one :document, as: :documentable    def self.find_sti_class(type_name)     activesupport::dependencies.constantize("db::ticket::#{sti_type_for(type_name)}")   end    self.inheritance_column = :type   self.store_full_sti_class = false    def self.sti_name     self.to_s.split('::').last   end  end  class db::ticket::train < db::ticket end  class ticket::airplain < db::ticket end 

when set association:

doc = document.new doc.documentable = db::ticket::train.first! # docuementable_type 'db::ticket' 

when preload polymorphic association:

db::ticket.where(id: [1,2]).preload(:document).to_a # select * documents documentable_id in (1,2) , documentable_type = 'ticket' 

i think because on association.writer uses name of base_class

module activerecord   # = active record belongs polymorphic association   module associations     class belongstopolymorphicassociation < belongstoassociation #:nodoc:       ...          def replace_keys(record)           super           owner[reflection.foreign_type] = record.class.base_class.name         end        ...     end   end end 

and on preloading uses sti_name of base_class

module activerecord   module associations     class preloader       class association #:nodoc:         ...          def build_scope           scope = klass.unscoped           ...            if options[:as]             scope.where!(klass.table_name => { reflection.type => model.base_class.sti_name })           end            ...         end          ...       end     end   end end 

why sql preload generates wrong documentable_type? mistake in using of sti/polymorhic or activerecord bug?