ruby on rails - Error: Unpermitted parameters with nested attributes -

i'm having problem saving contents of nested field. have 2 models incorporation , company. relate follows:

class company < activerecord::base   belongs_to :incorporation end  class incorporation < activerecord::base   has_one :company    accepts_nested_attributes_for :company end 

my aim create new company , incorporation entry in same form, using both incorporations controller , view.

(problem) however, each time attempt submit form, incorporation entry goes through company entry held unpermitted parameters error:

started post "/incorporations" 127.0.0.1 @ 2014-12-15 22:40:59 -0700 processing incorporationscontroller#create html   parameters: {"utf8"=>"✓", "authenticity_token"=>"lcj/ztnne/9l/ualycna8eae8vmmn010tos4t5e+zka=", "incorporation"=>{"title"=>"test", "company"=>{"name"=>"test"}}, "button"=>""} unpermitted parameters: company completed 500 internal server error in 4ms 

this particularly surprising beleive i've set strong params correctly. below controller.

class incorporationscontroller < applicationcontroller   def index   end    def show   end    def new @incorporation = incorporation.new @company = company.new   end    def create @incorporation = incorporation.new(incorporation_params)  if @incorporation.save   redirect_to @incorporation, notice: "successfuly saved incorporation info." else   render 'new' end   end    def edit   end    def show   end    private    def incorporation_params params.require(:incorporation).permit(:title, company_attributes: [:name, :state_corp, :street, :city, :state, :zip, :outstanding_common_stock, :fiscal_year_end_month, :fiscal_year_end_day])   end end 

the form partial i'm using follows:

<%= form_for @incorporation |f| %>   <div class="panel-body">     <%= f.text_field :title, input_html: { class: 'form-control' } %>     <h3>test</h3>     <%= f.fields_for @company |company| %>       <%= company.text_field :name, input_html: { class: 'form-control' } %>     <% end =%>   </div>   <%= f.button :submit, class: "btn btn-primary" %>  <% end =%> 

any ideas appreciated.

the usual way above

controller

  def new   @incorporation = incorporation.new   @company = @incorporation.build_company 

and in view

<%= form_for @incorporation |f| %>   <div class="panel-body">     <%= f.text_field :title, input_html: { class: 'form-control' } %>     <h3>test</h3>     <%= f.fields_for :company |company| %>       <%= company.text_field :name, input_html: { class: 'form-control' } %>     <% end =%>   </div>   <%= f.button :submit, class: "btn btn-primary" %> <% end %> 

the rest fine.