nested - Rails 4 has_many through - Cannot modify association -

i have dayitem model has 1 schoolprogram has many seminars.

class dayitem < activerecord::base   has_one :school_program, dependent: :destroy   has_many :seminars, through: :school_program    accepts_nested_attributes_for :school_program   accepts_nested_attributes_for :seminars, reject_if: :all_blank end  class schoolprogram < activerecord::base   belongs_to :day_item   has_many :seminars, dependent: :destroy    accepts_nested_attributes_for :seminars, allow_destroy: true, reject_if: :all_blank end  class seminar < activerecord::base   belongs_to :school_program end 

i using cocoon gem dynamic nested forms follows.

_form.html.haml:

= simple_form_for [@day, @day_item] |f|   = f.input :start_time   = f.simple_fields_for :school_program |form|     = form.input :school     = form.simple_fields_for :seminars |seminar|       = render 'seminar_fields', :f => seminar, :parent => form     .links       = link_to_add_association 'add seminar', form, :seminars 

_seminar_fields.html.haml:

.nested-fields.well.well-compact   .form-inline     = f.input :name     = link_to_remove_association "remove seminar", f 

but when try add seminar following exception.

 activerecord::hasmanythroughcantassociatethroughhasoneormanyreflection in etm::dayitemscontroller#update

cannot modify association 'dayitem#seminars' because source reflection class 'seminar' associated 'schoolprogram' via :has_many.

any appreciated.

circular reference in relationships (source reflection)

there may more 1 issue here, first 1 should addressed relationship seminars creates circular reference. declared in has_many in dayitem , has_one on schoolprogram, belongs parent class dayitem. please try change below our dayitem model. leave other models are, , let me know how goes.

class dayitem < activerecord::base   has_one :school_program, dependent: :destroy    accepts_nested_attributes_for :school_program end