Argthtjtr

I'm creating a blog using ruby on rails and while I'm coding the comments views and I got strange error, which I could not find a solution for

I'm tring to read user name from comment.user and it return this erorr

undefined method `name' for nil:NilClass

If I did inspect the user object, I see the data inside

<%= comment.user.inspect %>

I added the associations between the models correctly

User model

class User < ApplicationRecord

  # Include default devise modules. Others available are:

  # :confirmable, :lockable, :timeoutable and :omniauthable

  devise :database_authenticatable, :registerable,

         :recoverable, :rememberable, :trackable, :validatable





  has_many :comments, dependent: :destroy





end

Post model

class Post < ApplicationRecord

    belongs_to :user

    has_many :comments, dependent: :destroy

end

Comment model

class Comment < ApplicationRecord

  belongs_to :user

  belongs_to :post

end

comment View

<strong><%= comment.user.name %>:</strong><%= comment.body %><br><br>

Any help please?

Edit 2:

Comments controller code

class CommentsController < ApplicationController

  before_action :set_comment, only: [:show, :edit, :update, :destroy]



  # GET /comments

  # GET /comments.json

  def index

    @comments = Comment.all

  end



  # GET /comments/1

  # GET /comments/1.json

  def show

  end



  # GET /comments/new

  def new

    @post = Post.find params[:post_id]

  end



  # GET /comments/1/edit

  def edit

  end



  # POST /comments

  # POST /comments.json

  def create

    @comment = Comment.new(comment_params)

    @post = Post.find params[:post_id]

    @comment.user_id = current_user.id 

    respond_to do |format|

      if @comment.save

        format.html { redirect_to @post, notice: 'Comment was successfully created.' }

        format.json { render :show, status: :created, location: @comment }

      else

        format.html { render :new }

        format.json { render json: @comment.errors, status: :unprocessable_entity }

      end

    end

  end



  # PATCH/PUT /comments/1

  # PATCH/PUT /comments/1.json

  def update

    respond_to do |format|

      if @comment.update(comment_params)

        format.html { redirect_to @comment, notice: 'Comment was successfully updated.' }

        format.json { render :show, status: :ok, location: @comment }

      else

        format.html { render :edit }

        format.json { render json: @comment.errors, status: :unprocessable_entity }

      end

    end

  end



  # DELETE /comments/1

  # DELETE /comments/1.json

  def destroy

    @comment.destroy

    respond_to do |format|

      format.html { redirect_to comments_url, notice: 'Comment was successfully destroyed.' }

      format.json { head :no_content }

    end

  end



  private

    # Use callbacks to share common setup or constraints between actions.

    def set_comment

      @comment = Comment.find(params[:id])

    end



    # Never trust parameters from the scary internet, only allow the white list through.

    def comment_params

      params.require(:comment).permit(:body, :user_id, :post_id)

    end

end

Can you try?

<%= comment.user.name if comment.user %>

try this <%= comment.user.try(:name) %>.

It's possible that some comment doesn't contain user value.

try method is defined on Object class and NilClass class in Rails and it's not part of Ruby itself. You can use try when you are dealing with potential nil objects.

<%= comment.user.try(:name) %>.

When you use try in your case, NoMethodError exception will not be raised and nil will be returned instead of the receiving object is a nil object or NilClass.

For more info, you can look up this link