rails 4 grouped_collection_select don't work

Question

i've a problem with my app. I've two pair of models

the first:

          class Nazione < ActiveRecord::Base
                has_many :regiones

                accepts_nested_attributes_for :regiones
                attr_accessible :nome, :regiones_attributes
          end

and

         class Regione < ActiveRecord::Base
               belongs_to :nazione
               attr_accessible :nome, :nazione_id
         end

and the second pair:

     class Macrocategorie < ActiveRecord::Base
       has_many :categories
       accepts_nested_attributes_for :categories
       attr_accessible :nome, :categories_attributes
     end

and

      class Categorie < ActiveRecord::Base
         belongs_to :macrocategorie

         attr_accessible :nome, :macrocategorie_id
      end

they are used for the form in another model named Modulo1 :

     class Modulo1 < ActiveRecord::Base
         attr_accessible :nazione_organizzazione,:regione_organizzazione,:macrocat_sett_scient ,:cat_sett_scient

in the Modulo1's form when I use:

      <%= f.label :Nazione%><br />
      <%= f.collection_select :nazione_organizzazione, Nazione.order(:nome), :nome, 
                                         :nome,{:prompt => "Seleziona una Nazione"} %>

     <%= f.label :Regione %><br>
     <%= f.grouped_collection_select :regione_organizzazione, Nazione.order(:nome), 
               :regiones, :nome, :nome, :nome, {:prompt => "Seleziona una Regione"} %>

it works! but if I use

     <%= f.label :Settore_Scientifico %><br>
     <%= f.collection_select :macrocat_sett_scient, Macrocategorie.order(:nome), :nome, 
                                  :nome, {:prompt => "Seleziona una Macrocategoria"} %>
     <%= f.grouped_collection_select :cat_sett_scient, 
                           Macrocategorie.order(:nome),:categories,:nome, :nome,:nome,  
                                              {:prompt => "Seleziona una Categoria"} %>

it don't work!!! the errore is this:

      uninitialized constant Macrocategorie::Category

Could anyone help me to solve this problem?

Answer 1

Rails fails to identify which class belongs on the other end of the association because your class names are not in English. You can set the class name explicitly:

class Macrocategorie < ActiveRecord::Base
  has_many :categories, class_name: 'Categorie'
end

Another alternative is to define a new inflector in config/intializers/inflections.rb

ActiveSupport::Inflector.inflections do |inflect|
  inflect.irregular 'categorie', 'categories'
end