Why do I get "NameError in Discussions"? - ruby-on-rails

Question

I'm currently working on a Ruby on Rails application that involves users creating discussions and commenting with microposts. It's a pretty simple concept but I'm new and have run into some trouble.
When trying to look at the discussions page (index of discussion) I get the error "NameError in Discussions#index":
undefined local variable or method `discussion' for #<#<Class:0x00000100c6e020>:0x0000010380edd8>
This is my Discussion controller:
class DiscussionsController < ApplicationController
before_filter :signed_in_user, only: [:index, :edit, :update]
def show
#user = User.find(params[:id])
#discussions = #user.discussion.paginate(page: params[:page])
#microposts = #user.micropost.paginate(page: params[:page])
end
def index
#discussions = Discussion.all
end
def create
#discussion = current_user.discussions.build(params[:discussion])
if #discussion.save
flash[:success] = "Discussion Started!"
redirect_to root_url
else
render 'static_pages/home'
end
end
def destroy
end
def edit
end
def update
end
def new
end
end
This is my Micropost form:
<% #micropost = Micropost.new %>
<% #micropost.discussion_id = discussion.id %>
<%= form_for(#micropost) do |f| %>
<%= render 'shared/error_messages', object: f.object %>
<div class="field">
<%= f.text_area :content, placeholder: "Compose new micropost..." %>
</div>
<%= f.hidden_field :discussion_id, discussion.id%>
<%= f.submit "Post", class: "btn btn-large btn-primary" %>
<% end %>
This is my Discussion partial:
<% content_for :script do %>
<%= javascript_include_tag 'hover_content' %>
<% end %>
<li>
<div class = "intro-bar"><span class = "intro"><%=discussion.intro %></span></div>
<div class = "content-bar">
<span class = "content"><%= discussion.content %></span>
<div class = "buttons">
<div class = "vote-neg"><%= link_to "Break Up", signup_path,class: "btn btn-large btn-breakup" %></div>
<div class = "vote-plus"><%= link_to "Stay Together", signup_path,class: "btn btn-large btn-staytogether" %></div>
</div>
</div>
</li>
<span class = "timestamp">
Posted <%= time_ago_in_words(discussion.created_at) %> ago.
</span>
<div class = "comments">
<% discussion.microposts.each do |micropost| %>
<li>
<div class = "post-comment"><%= micropost.content%></div>
</li>
<% end %>
</div>
<% if signed_in? %>
<div class = "row">
<aside class = "span4">
<section>
<%= render 'shared/micropost_form', :locals => {:discussion => discussion }%>
</section>
</aside>
</div>
<% end %>
This is my Micropost controller:
class MicropostsController < ApplicationController
before_filter :signed_in_user, only: [:create, :destroy]
def index
end
def create
#discussion = current_user.discussions.new
#micropost = current_user.microposts.build(params[:micropost])
if #micropost.save
flash[:success] = "Posted!"
redirect_to root_url
else
render 'static_pages/home'
end
end
def destroy
end
end
This is my Discussion model:
class Discussion < ActiveRecord::Base
attr_accessible :content, :intro
has_many :microposts, dependent: :destroy
belongs_to :user
validates :content, presence: true, length: { maximum: 600 }
validates :intro, presence: true
default_scope order: 'discussions.created_at DESC'
end
This is my User model:
class User < ActiveRecord::Base
attr_accessible :email, :username, :age, :sex, :points, :password, :password_confirmation
has_secure_password
has_many :microposts, dependent: :destroy
has_many :discussions, dependent: :destroy
before_save {|user| user.email = email.downcase}
before_save :create_remember_token
validates :username, presence: true, length: {maximum: 15}
VALID_EMAIL_REGEX = /\A[\w+\-.]+#[a-z\d\-.]+\.[a-z]+\z/i
validates :email, presence: true, format: { with: VALID_EMAIL_REGEX }, uniqueness: {case_sensitive: false}
validates :age, presence: true
validates :sex, presence: true
validates :password, presence: true, length: { minimum: 6 }
validates :password_confirmation, presence: true
private
def create_remember_token
self.remember_token = SecureRandom.urlsafe_base64
end
end
This is my Discussion index:
<% provide(:title, "Discussions") %>
<h1>Discussions</h1>
<ul class = "discussions">
<% #discussions.each do |discussion| %>
<li>
<%= render :partial =>"discussions/discussion", :locals=>{:discussion=>discussion} %>
</li>
<% end %>
</ul>

Answer 1

Try rewriting this line:
<%= render 'shared/micropost_form', :locals => {:discussion => discussion }%>
as:
<%= render 'shared/micropost_form', :discussion => discussion %>