Double Render Error

Question

前提・実現したいこと

部屋の中で投稿されたメッセージを削除しようと、削除ボタンを押すと、メッセージは削除される
（他のメッセージも３つくらい同時に削除されてしまう...）のですが
下記のようなエラーメッセージが出てきます。

【削除ボタン画面のイメージ】

発生している問題・エラーメッセージ

該当のソースコード

class MessagesController < ApplicationController
  def index
    @comment = Comment.new
    @message = Message.new
    @room = Room.find(params[:room_id])
    @messages = @room.messages.includes(:user).order("created_at DESC")
    @users = @room.users.order("student_number ASC")
  end
  
  def new
    @room = Room.find(params[:room_id])
    @comment = Comment.new
    @message = Message.new
  end
  
  def show
    @comment = Comment.new
    @comments = @message.comments.includes(:user)
  end

  def create
    @room = Room.find(params[:id])
    @message = @room.messages.new(message_params)
    if @message.save
      redirect_to room_messages_path(@room)
    else
      redirect_to room_messages_path(@room)
    end
  end

  def destroy
    @room = Room.find(params[:id])
    @messages = @room.messages
    @messages.each do |message|
    if message.destroy
       redirect_to room_messages_path(message, message.room)
    else
      render :new
    end
  end       
  end

  private

  def message_params
    params.require(:message).permit(:content, :image).merge(user_id: current_user.id)
  end
end

【削除実行後のログ】

Started DELETE "/rooms/131/messages/1" for ::1 at 2020-11-08 11:25:46 +0900
Processing by MessagesController#destroy as HTML
  Parameters: {"authenticity_token"=>"auEO4Gz8UK3Eyf8lFt/iqxVzsU1pL2UgBOYPV8+vyftXr6GzYYHj18L4GReMzXEPzlrDslt9QerySbS80Ot4iA==", "room_id"=>"131", "id"=>"1"}
  User Load (0.3ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 2 ORDER BY `users`.`id` ASC LIMIT 1
  Room Load (0.2ms)  SELECT `rooms`.* FROM `rooms` WHERE `rooms`.`id` = 1 LIMIT 1
  ↳ app/controllers/messages_controller.rb:32:in `destroy'
  Message Load (0.2ms)  SELECT `messages`.* FROM `messages` WHERE `messages`.`room_id` = 1
  ↳ app/controllers/messages_controller.rb:34:in `destroy'
   (0.1ms)  BEGIN
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
  ActiveStorage::Attachment Load (0.3ms)  SELECT `active_storage_attachments`.* FROM `active_storage_attachments` WHERE `active_storage_attachments`.`record_id` = 131 AND `active_storage_attachments`.`record_type` = 'Message' AND `active_storage_attachments`.`name` = 'image' LIMIT 1
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
  Message Destroy (0.2ms)  DELETE FROM `messages` WHERE `messages`.`id` = 131
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
   (0.5ms)  COMMIT
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
Redirected to http://localhost:3000/rooms/131/messages/1
   (0.1ms)  BEGIN
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
  ActiveStorage::Attachment Load (0.3ms)  SELECT `active_storage_attachments`.* FROM `active_storage_attachments` WHERE `active_storage_attachments`.`record_id` = 132 AND `active_storage_attachments`.`record_type` = 'Message' AND `active_storage_attachments`.`name` = 'image' LIMIT 1
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
  Message Destroy (0.2ms)  DELETE FROM `messages` WHERE `messages`.`id` = 132
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
   (0.2ms)  COMMIT
  ↳ app/controllers/messages_controller.rb:35:in `block in destroy'
Redirected to 
Completed 500 Internal Server Error in 15ms (ActiveRecord: 2.7ms | Allocations: 11677)


AbstractController::DoubleRenderError (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".):

【routes.rb】

Rails.application.routes.draw do
  devise_for :users
  get 'messages/index'
  get 'comments/index'
  get 'responses/create' => 'responses#create'
  root to: "rooms#index"
  resources :users
  resources :rooms do
    resources :messages
  end

  resources :messages do
    resources :comments
  end

  resources :comments do
    resources :agrees, only: [:create, :destroy]
  end

  resources :comments do
    resources :responses, only: [:new, :create, :destroy]
  end

end

Comments

[m.ts10806]

Railsって結構エラーメッセージ懇切丁寧なのですけど、エラーメッセージ読んでませんか？
https://qiita.com/cannorin/items/eb062aae88bfe2ad6fe5

Answer 1

エラーメッセージにあるまま、です。
ひとつのアクションでは一回しか宣言できません。
みため　if-else-end にわけられて１つにみえますが、@messages.each の中にあるので、@messages.size回宣言されています。