Rails 6 + Cocoon双层嵌套表单渲染问题求助

环境与需求 #

• 基于Rails 6 + Cocoon原生JS版开发测验类网站
• 需在单页完成测验、问题及对应答案的创建，采用双层嵌套表单实现

模型代码 #

Test模型 #

class Test < ApplicationRecord
  belongs_to :author, class_name: 'Teacher'
  belongs_to :article, optional: true

  has_many :questions, dependent: :destroy

  accepts_nested_attributes_for :questions, reject_if: :all_blank
end

Question模型 #

class Question < ApplicationRecord
  belongs_to :test

  has_many :answers, dependent: :destroy

  accepts_nested_attributes_for :answers, reject_if: :all_blank

  validates :title, presence: true
end

Answer模型 #

class Answer < ApplicationRecord
  belongs_to :question

  validates :content, presence: true
  validate :validate_max_answer_amount, on: :create

  scope :correct, -> { where(correct: true) }

  private

  def validate_max_answer_amount
    errors.add :base, :invalid_amount, message: 'Too many answers!' if question.answers.count >= 5
  end
end

问题现象 #

• 初始表单显示正常
• 添加答案后，新字段未显示在旧字段下方
• 添加问题后，新问题字段未在已有字段下方显示，且无默认答案输入字段

视图代码 #

tests/_form.html.slim #

=render 'shared/errors', object: @test

=form_with model: [:teacher, @test], local: true do |f|
  =f.number_field :author_id, class: 'hidden'
  =f.number_field :article_id, class: 'hidden'

  .mb-3.add-questions
    p
      | Add questions:
    .mb-3
      =f.fields_for :questions do |q|
        =render 'teacher/questions/question_fields', f: q
      br
      br
      =link_to_add_association 'Add one more question', f, :questions, partial: 'teacher/questions/question_fields'

  =f.submit 'Submit', class: 'btn btn-outline-success btn-lg mb-4'

questions/_question_fields.html.slim #

.mb-3.row
  .col-sm-2.col-form-label
    =f.label :title, 'Title'
  .col-sm-10.col-form-label
    =f.text_field :title, class: 'form-control'

=f.fields_for :answers do |a|
  =render 'teacher/answers/answer_fields', f: a

=link_to_add_association 'Add one more answer', f, :answers, partial: 'teacher/answers/answer_fields'

answers/_answer_fields.html.slim #

.mb-1.row
  .col-sm-1
  .col-sm-2.col-form-label
    =f.label :content, 'Enter content'
  .col-sm-8.col-form-label
    =f.text_field :content, class: 'form-control'
  .col-sm-1.col-form-label
    =f.check_box :correct, {class: 'form-check-input'}, true, false

已尝试方案及求助 #

移除questions/_question_fields.html.slim中的=render 'teacher/answers/answer_fields'代码后，新增问题无答案字段的问题仍未解决，也未找到答案字段显示位置异常的解决方法，恳请协助！

内容的提问来源于stack exchange，提问作者hjbaa