ruby on rails - Model callbacks not working with self referential association -

i having model evaluation has many sub evaluations (self refential)

class evaluation < applicationrecord    has_many :sub_evaluations, class_name: "evaluation", foreign_key: "parent_id", dependent: :destroy    before_save :calculate_score    def calculate_score     #   end  end 

i creating , updating evaluation sub evaluations nested attributes.

calculate_score method triggered on sub evaluation creation not while updating. have tried before_update , after_validation. nothing seems working.

evaluation form

= form_for @evaluation |f|   ...   = f.fields_for :sub_evaluations |sub_evaluation|    ... 

what seems issue?

this article helped me fix issue.

child callback isn't triggered because parent isn't "dirty".

the solution in article "force" dirty calling attr_name_will_change! on parent attribute that, in fact, not change.

here updated model code:

class evaluation < applicationrecord    has_many :sub_evaluations, class_name: "evaluation", foreign_key: "parent_id", dependent: :destroy    before_save :calculate_score    def calculate_score     #   end    def exam_id= val     exam_id_will_change!     @exam_id = val   end  end 

see active model dirty in rails api