def update
   @datum = OtherDatum.friendly.find_or_initialize_by(slug: params[:id]) do |data|
     data.title = params[:other_datum][:title]
     data.number = params[:other_datum][:number]
     data.roles = params[:other_datum][:roles]
    end
    byebug
    # if @datum.update(other_datum_params.merge(slug: params[:id]))
    if @datum.valid?
    #     @datum.save
    #     redirect_to({:action => :index}, {:notice => 'Data updated'})
    else
    #   puts @datum.object_id
    byebug
      render :edit
    end
  end

  def other_datum_params
    params.require(:other_datum).permit(:title, :number, :roles, :slug)
  end


Log:


[22, 31] in /home/usr/Dropbox/tech/tech/app/controllers/admin/other_data_controller.rb
   22:      data.number = params[:other_datum][:number]
   23:      data.roles = params[:other_datum][:roles]
   24:     end
   25:     byebug
   26:     # if @datum.update(other_datum_params.merge(slug: params[:id]))
=> 27:     if @datum.valid?
   28:     #     @datum.save
   29:     #     redirect_to({:action => :index}, {:notice => 'Data updated'})
   30:     else
   31:     #   puts @datum.object_id
(byebug) @datum
#<OtherDatum id: nil, title: "Тест", number: nil, created_at: nil, updated_at: nil, slug: "satellite", roles: [""]>
(byebug) c

[28, 37] in /home/usr/Dropbox/tech/tech/app/controllers/admin/other_data_controller.rb
   28:     #     @datum.save
   29:     #     redirect_to({:action => :index}, {:notice => 'Data updated'})
   30:     else
   31:     #   puts @datum.object_id
   32:     byebug
=> 33:       render :edit
   34:     end
   35:   end
   36:
   37:   def other_datum_params
(byebug) @datum
#<OtherDatum id: nil, title: "Тест", number: nil, created_at: nil, updated_at: nil, slug: nil, roles: [""]>
(byebug) I, [2020-02-28T17:09:56.302596 #5738]  INFO -- : SIGWINCH ignored because we're not daemonized