Ruby on Rails 5 Nested comments not being created - ruby-on-rails

Question

I'm a beginner in rails and trying to create a Reddit type blog page. Currently, I'm working on nested comments so the user is able to reply to comments. In my app I have forums, posts and comments. Creating posts and forums has worked perfectly, also posting comments until I tried nesting replies. My code looks like this (Forums and Users models/controllers have been omitted) :
My Comment model:
class Comment < ApplicationRecord
belongs_to :commentable, polymorphic: true
belongs_to :user
has_many :comments, as: :commentable
end`
My Post model:
class Post < ApplicationRecord
belongs_to :forum
belongs_to :user
has_many :comments, as: :commentable, dependent: :destroy
end
My posts_controller:
class PostsController < ApplicationController
def index
#posts = Post.all
end
def show
#post = find_post
end
def new
#post = Post.new
end
def edit
#post = find_post
end
def create
#forum = Forum.find(params[:forum_id])
#post = #forum.posts.create(post_params.merge(user_id: current_user.id))
redirect_to forum_path(#forum)
end
def update
#post = find_post
if #post.update(post_params)
redirect_to forum_path
else
render 'show'
end
end
def destroy
#post = find_post
#post.destroy
redirect_to forum_path
end
private
def post_params
params.require(:post).permit(:title, :content)
end
private
def find_post
#forum = Forum.find(params[:forum_id])
#forum.posts.find(params[:id])
end
end
My comments_controller:
class CommentsController < ApplicationController
before_action :find_commentable
def index
#comments = Comment.all
end
def new
#comment = Comment.new
end
def create
#comment = #commentable.comments.create(comment_params.merge(user_id: current_user.id))
if #comment.save
#post = Post.find_by_id(params[:post_id])
redirect_to forum_post_path(#post.forum_id, #post), notice: 'Your comment was successfully posted!'
else
redirect_to forum_post_path(#post.forum_id, #post), notice: 'error :('
end
end
private
def comment_params
params.require(:comment).permit(:content)
end
private
def find_commentable
#commentable = Comment.find_by_id(params[:comment_id]) if params[:comment_id]
#commentable = Post.find_by_id(params[:post_id]) if params[:post_id]
end
end
My views/comments/_comment:
<li>
<%= comment.content %>
<small>Submitted <%= time_ago_in_words(comment.created_at) %> ago</small>
<h2>Add a Reply:</h2>
<%= form_with(model: [ comment, comment.comments.build ], local: true) do |form| %>
<p>
<%= form.text_area :content, placeholder: "Add a Reply" %><br/>
<%= form.submit %>
</p>
<% end %>
<ul>
<%= render partial: 'comments/comment', collection: comment.comments if comment.comments.any? %>
</ul>
<%= link_to 'Back', forum_post_path(#forum, #post) %>
My views/post/show:
<small>Submitted <%= time_ago_in_words(#post.created_at) %> ago</small>
<h3>Comments</h3>
<ul>
<%= render(partial: 'comments/comment', collection: #post.comments) if #post.comments.any?%>
</ul>
<h2>Add a comment:</h2>
<%= form_with(model: [ #post, #post.comments.build ], local: true) do |form| %>
<%= form.text_field :content, placeholder: "Add a comment" %><br/>
<%= form.submit "Add Comment" %>
<% end %>
<%= link_to 'Back', forum_path(#forum) %>
<%= link_to 'All posts', forum_posts_path(#post.forum_id) %>
<%= link_to 'All comments', post_comments_path(#post) %>
</li>
My routes:
resources :posts do
resources :comments
end
resources :comments do
resources :comments
end
The first errors I kept getting were that every time I submitted a comment in view/posts/show the comment wouldn't create. Now, views/comments/_comment lifts the error:
Showing /example/app/views/comments/_comment.html.erb where line #3 raised:
nil can't be converted to a Time value
<small>Submitted <%= time_ago_in_words(comment.created_at) %> ago</small>
after I submit a new comment. Any help regarding this error is appreciated or related to my main goal, I have been circling around this for a long time. Thanks!

Answer 1

The problem here is that new comment is initialized(for the comment which is being rendered) every time the partial is trying to render the comment.
Check out the following byebug output:
(byebug) pp comment.comments
[#<Comment:0x007f35ce11d900
id: 5,
content: "DEF",
commentable_id: 4,
commentable_type: "Comment",
user_id: 1,
created_at: Wed, 30 May 2018 06:53:51 UTC +00:00,
updated_at: Wed, 30 May 2018 06:53:51 UTC +00:00>,
#<Comment:0x007f35ce2a3388
id: nil,
content: nil,
commentable_id: 4,
commentable_type: "Comment",
user_id: nil,
created_at: nil,
updated_at: nil>]
This line is the culprit:
<%= form_with(model: [ comment, comment.comments.build ], local: true) do |form| %>
comment.comments.build initializes a new empty Comment which is your code then tries to render and throws the error as it does not have created_at.
And then the newly initialized comment is being rendered by the code.
Replacing app/views/comments/_comment#13 with the following will resolve the issue:
<%= render(partial: 'comments/comment', collection: comment.comments.where.not(content: nil)) if comment.comments.any? %>