Can't get nested_form to show validation errors - ruby-on-rails

Question

I haven't had a problem with validations before but this time I am having issues with nested_form validations. I am using Twitter Bootstrap and can get flash errors to show with, say, this:
def create
#recipe = current_user.recipes.new(params[:recipe])
if #recipe.save
redirect_to my_recipes_path, :notice => "Thanks #{current_user.name} Recipe sucessfully created."
else
render :action => 'new'
end
end
For my flash messages I use this in my app/layouts
<% flash.each do |name, msg| %>
<div class="alert alert-<%= name == :notice ? "success" : "error" %>">
<a class="close" data-dismiss="alert">×</a>
<%= content_tag :div, msg, :id => "flash_#{name}" if msg.is_a?(String) %>
</div>
<% end %>
So I thought I would try and just get one of the validators working, so my model
class Recipe < ActiveRecord::Base
belongs_to :user
delegate :name, :to => :user, :prefix => :user, :allow_nil => true
belongs_to :country
has_many :ingredients
has_many :preperations
has_many :favourites
validates_presence_of :dish_name
and my form
<%= nested_form_for #recipe do |f| %>
<div class="field_with_errors">
<%= f.label :dish_name, "Dish Name" %>
<%= f.text_field :dish_name, :placeholder => "Enter Dish Name" %>
</div>
<%= f.label :country_id, "Country Of Origin" %>
<%= f.collection_select(:country_id, Country.all, :id, :name, :prompt => 'Please select country') %>
<%= f.label :category, "Category" %>
<%= f.select :category, [['Starter'], ['Main Course'], ['Desserts'], ['Vegeterian']], {:include_blank => 'Please Select'} %>
<%= f.label :difficulty, "Difficulty Level" %>
<%= f.select :difficulty, [['Beginner'],['Intermediate'],['Expert']], {:include_blank => 'Please Select'} %>
<%= f.label :preperation_time, "Preperation Time (Mins)" %>
<%= f.select :preperation_time, [['15-30 Mins'],['30-60 Mins'],['60-120 Mins']], {:include_blank => 'Please Select'} %>
<%= f.fields_for :ingredients do |ing| %>
Ingredient<br>
<%= ing.text_field :ingredient_name , :placeholder => "Enter Ingredient Here" %><br>
<% end %>
<%= f.link_to_add "Add an Ingredient", :ingredients %><br>
<%= f.fields_for :preperations do |prep| %>
Preperation Step<br>
<%= prep.text_field :prep_steps , :placeholder => "Enter step Here" %><br>
<% end %>
<%= f.link_to_add "Add a step", :preperations %><br>
<%= f.label :description, "Description of Recipe" %>
<%= f.text_area :description, :size=> "60x10" %></br>
<%= f.file_field :avatar %><br>
<%= f.submit "Submit Recipe" %>
<% end %>
I am fairly new to Rails so I may have missed something fundamental, or is it because it is a nested form and it behaves differently?
Edit
Output of <%= flash debug %>:
--- !ruby/object:ActionDispatch::Flash::FlashHash
used: !ruby/object:Set
hash: {}
closed: false
flashes: {}
now:

Answer 1

It seems you're not actually providing your flash hash with any messages to work with. A quick solution might be something like:
def create
#recipe = current_user.recipes.new(params[:recipe])
if #recipe.save
redirect_to my_recipes_path, :notice => "Thanks #{current_user.name} Recipe sucessfully created."
else
flash[:error] = #recipe.errors.full_messages.to_sentence
render :action => 'new'
end
end