Question

I got polymorphic has many through association

# a/m/documnet.rb
class Document < ActiveRecord::Base
 has_many :possessions, as: :belonging
 has_many :clients, :through => :possessions, :source => :owner, :source_type => 'Client'
end

in console

Document.new.clients 
#=> []

in views with simple form

= f.association :clients, as: :check_boxes, collection: Client.all

it works without problem.

—

Issue starts when I want to dynamically associate has many resources

class Document < ActiveRecord::Base
  has_many :possessions, as: :belonging

  def self.possession_owner_classes
     [Client, SomethingElse]
  end
  possession_owner_classes.each do |possession_class|
    has_many possession_class.model_name.underscore.pluralize, :through => :possessions,  :source => :owner, :source_type => possession_class.model_name
  end
end

in console

Document.new.clients 
#=> []

in views with simple form

= f.association :clients, as: :check_boxes, collection: Client.all

will throw

Association :clients not found

so Rails know about this association but simple form doesn’t :-/ any ideas please ?

Answer 1

ok I found the error,

has_many possession_class.model_name.underscore.pluralize, :through => :possessions,  :source => :owner, :source_type => possession_class.model_name

should be

has_many possession_class.model_name.underscore.pluralize.to_sym, :through => :possessions,  :source => :owner, :source_type => possession_class.model_name

so association name must be symbol not string

 :clients   # ok
 'clients'  # will blow up

huh :-\