这样做的目的是让评论属于属于用户的文章：

class User < ApplicationRecord
  has_one :profile
  has_many :articles, -> {order 'published_at DESC, title ASC'}, dependent: :nullify          
  has_many :replies, through: :articles, source: :comments
end

class Article < ApplicationRecord
  validates :title, :body, presence: true 

  belongs_to :user
  has_and_belongs_to_many :categories
  has_many :comments

  def long_title
    "#{title} - #{published_at}"
  end
end

class Comment < ApplicationRecord
  belongs_to :article
end

我从控制台得到的是：

irb(main):048> user.replies
=> []

但是！

irb(main):049> user.replies.all
  Comment Load (0.7ms)  SELECT "comments".* FROM "comments" INNER JOIN "articles" ON "comments"."article_id" = "articles"."id" WHERE "articles"."user_id" = ? ORDER BY published_at DESC, title ASC  [["user_id", 3]]
=> 
[#<Comment:0x0000ffff802d1420
  id: 1,
  article_id: 1,
  name: "guest",
  email: "[email protected]",
  body: "comment text",
  created_at: Tue, 03 Oct 2023 22:05:04.136672000 UTC +00:00,
  updated_at: Tue, 03 Oct 2023 22:05:04.136672000 UTC +00:00>]

有人能解释一下为什么用户.replies是空的，但.all显示。
当我只返回Articles.last.comments（只有1条评论和文章）时，它会返回评论。那么，为什么当我要求的时候，文章没有把它交给用户呢？