undefined method `errors' for #<Comment cannot get errors - ruby-on-rails

Question

So I'm getting the following error:
undefined method `errors' for #<Comment::ActiveRecord_Associations_CollectionProxy:0x00007f1a3e2ecf48>
I can get the comment count and other things like that, however, I can't display any errors of the validations.
Here is what I have in terms of my code
_new_comment
<% if signed_in? %>
<div class="row">
<%= form_with(model: [#product, #product.comments.build], local: true) do |f| %>
<% if #product.comments.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#product.comments.errors.count, "error") %> prohibited this comment from being saved:</h2>
<ul>
<% #product.comments.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
comments_controller
class CommentsController < ApplicationController
def create
#product = Product.find(params[:product_id])
#comment = #product.comments.new(comment_params)
#comment.user = current_user
#comment.save
respond_to do |format|
if #comment.save
format.html { redirect_to #product, notice: 'Review was successfully created.' }
format.json { render :show, status: :created, location: #product }
else
format.html { redirect_to #product, alert: 'Review was not saved successfully.' }
format.json { render json: #comment.errors, status: :unprocessable_entity }
end
end
end
def destroy
end
private
def comment_params
params.require(:comment).permit(:user_id, :body, :rating)
end
end
Any help here is appreciated.

Answer 1

Issues
You can not access errors on an ActiveRecord::Relation object, but on individual Comment objects.
In your controller action create, you do redirect_to(#product) on failing to save the comment, which will ignore already built #comment object and build a new one (through form_with(model: [#product, #product.comments.build])) when rendering the comment form. Instead, you need to only render the product page with already built #comment object.
You have #comment.save twice in your create action.
Solution
products_controller.rb
def show
# your current logic
#comment = #product.comments.build
# render
end
comments_controller.rb
class CommentsController < ApplicationController
def create
#product = Product.find(params[:product_id])
#comment = #product.comments.new(comment_params)
#comment.user = current_user
respond_to do |format|
if #comment.save
format.html { redirect_to #product, notice: 'Review was successfully created.' }
format.json { render :show, status: :created, location: #product }
else
format.html { render 'products/show', alert: 'Review was not saved successfully.' }
format.json { render json: #comment.errors, status: :unprocessable_entity }
end
end
end
private
def comment_params
params.require(:comment).permit(:user_id, :body, :rating)
end
end
_new_comment.html.erb
<%= form_with(model: [#product, #comment], local: true) do |f| %>
<% if #comment.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#comment.errors.count, "error") %> prohibited this comment from being saved:</h2>
<ul>
<% #comment.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<% end %>