简单控制器的双重渲染错误

我的api rails应用程序中出现了一个奇怪的错误:

AbstractController::DoubleRenderError in Api::V1::AdsController#restaurant
Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like "redirect_to(...) and return".

我找到了这一页 https://api.rubyonrails.org/classes/ActionController/Base.html 关于双重渲染,但我并没有真正理解它们的含义以及它如何应用到我的情况。

我的控制器里有这个:

class Api::V1::AdsController < Api::V1::BaseController
  before_action :set_ad, only: [ :show ]

  def index
    @ads = policy_scope(Subcategory.find_by(nombre: "Restaurantes").ads)
  end

  def restaurant
    @restaurants = policy_scope(Subcategory.find_by(nombre: "Restaurantes").ads)
  end

  def show
  end

  private

  def set_ad
    @ad = Ad.find(params[:id])
    authorize @ad
  end
end

在我看来:

Rails.application.routes.draw do
  devise_for :users
  namespace :api, defaults: { format: :json } do
    namespace :v1 do
      resources :ads, only: [ :index, :show ] do
        collection do
          get 'restaurant', to: 'ads#restaurant'
        end
      end
    end
  end
  root to: 'pages#home'
  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
end

我有三种观点: 索引.json.jbuilder:

json.array! @ads do |ad|
  json.extract! ad,
  :id,
  :empresa,
  :direccion_principal,
  :tel,
  :email_principal,
  :web,
  :facebook,
  :instagram,
  :twitter,
  :isla
end

restaurant.json.jbuilder=与index相同

显示.json.jbuilder:

json.extract! @ad, :id, :empresa, :direccion_principal

有人能看到这里的问题吗?

编辑:

AdPolicy:

class AdPolicy < ApplicationPolicy
  class Scope < Scope
    def resolve
      scope.all
    end
  end

  def show?
    true
  end
end

基本控制器:

class Api::V1::BaseController < ActionController::API
  include Pundit

  after_action :verify_authorized, except: :index
  after_action :verify_policy_scoped, only: :index

  rescue_from StandardError,                with: :internal_server_error
  rescue_from Pundit::NotAuthorizedError,   with: :user_not_authorized
  rescue_from ActiveRecord::RecordNotFound, with: :not_found

  private

  def user_not_authorized(exception)
    render json: {
      error: "Unauthorized #{exception.policy.class.to_s.underscore.camelize}.#{exception.query}"
    }, status: :unauthorized
  end

  def not_found(exception)
    render json: { error: exception.message }, status: :not_found
  end

  def internal_server_error(exception)
    if Rails.env.development?
      response = { type: exception.class.to_s, message: exception.message, backtrace: exception.backtrace }
    else
      response = { error: "Internal Server Error" }
    end
    render json: response, status: :internal_server_error
  end
end