ActsAsTaggableOn 未定义方法 '[]=' for nil:NilClass - 创建操作

Question

提前感谢您的帮助。

下面，在我的帖子底部，我更新了这个问题的修复程序，部分感谢 Narasimha Reddy。希望它对升级到 Rails 5.2 后遇到类似问题的人有所帮助。更新：ActsAsTaggableOn 6.0 已发布并修复了此问题。

我最近升级到 Rails 5.2、Ruby 2.5，并将我的开发数据库切换到 PostgreSQL（9.3.18，gem：1.0.0）。以前，此问题并未发生，此后仅进行了上述更改。我将 ActsAsTaggableOn (5.0.0) gem 用于使用两个列表的评论表单：love_list 和改进列表。现在，在提交表单时，我收到以下错误：

    NoMethodError in CityReviewsController#create
undefined method `[]=' for nil:NilClass Extracted source (around line 56)

 56:   @new_city_review = @city.city_reviews.build(city_review_params)
    @new_city_review.user_id = current_user.id  

Rails.root: /home/ubuntu/mvp1
Application Trace | Framework Trace | Full Trace
acts-as-taggable-on (5.0.0) lib/acts_as_taggable_on/taggable/core.rb:206:in `process_dirty_object'
acts-as-taggable-on (5.0.0) lib/acts_as_taggable_on/taggable/core.rb:184:in `set_tag_list_on'
acts-as-taggable-on (5.0.0) lib/acts_as_taggable_on/taggable/core.rb:45:in `love_list='
activemodel (5.2.0) lib/active_model/attribute_assignment.rb:51:in `public_send'
activemodel (5.2.0) lib/active_model/attribute_assignment.rb:51:in `_assign_attribute'
activemodel (5.2.0) lib/active_model/attribute_assignment.rb:44:in `block in _assign_attributes'
activemodel (5.2.0) lib/active_model/attribute_assignment.rb:43:in `each'
activemodel (5.2.0) lib/active_model/attribute_assignment.rb:43:in `_assign_attributes'
activerecord (5.2.0) lib/active_record/attribute_assignment.rb:23:in `_assign_attributes'
activemodel (5.2.0) lib/active_model/attribute_assignment.rb:35:in `assign_attributes'
activerecord (5.2.0) lib/active_record/core.rb:314:in `initialize'
activerecord (5.2.0) lib/active_record/inheritance.rb:66:in `new'
activerecord (5.2.0) lib/active_record/inheritance.rb:66:in `new'
activerecord (5.2.0) lib/active_record/reflection.rb:154:in `build_association'
activerecord (5.2.0) lib/active_record/associations/association.rb:270:in `build_record'
activerecord (5.2.0) lib/active_record/associations/collection_association.rb:106:in `build'
activerecord (5.2.0) lib/active_record/associations/collection_proxy.rb:319:in `build'
app/controllers/city_reviews_controller.rb:56:in `create'
actionpack (5.2.0) lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack (5.2.0) lib/abstract_controller/base.rb:194:in `process_action'
actionpack (5.2.0) lib/action_controller/metal/rendering.rb:30:in `process_action'
actionpack (5.2.0) lib/abstract_controller/callbacks.rb:42:in `block in process_action'
activesupport (5.2.0) lib/active_support/callbacks.rb:132:in `run_callbacks'
actionpack (5.2.0) lib/abstract_controller/callbacks.rb:41:in `process_action'
actionpack (5.2.0) lib/action_controller/metal/rescue.rb:22:in `process_action'
actionpack (5.2.0) lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
activesupport (5.2.0) lib/active_support/notifications.rb:168:in `block in instrument'
activesupport (5.2.0) lib/active_support/notifications/instrumenter.rb:23:in `instrument'
activesupport (5.2.0) lib/active_support/notifications.rb:168:in `instrument'
actionpack (5.2.0) lib/action_controller/metal/instrumentation.rb:32:in `process_action'
actionpack (5.2.0) lib/action_controller/metal/params_wrapper.rb:256:in `process_action'
activerecord (5.2.0) lib/active_record/railties/controller_runtime.rb:24:in `process_action'
actionpack (5.2.0) lib/abstract_controller/base.rb:134:in `process'
actionview (5.2.0) lib/action_view/rendering.rb:32:in `process'
actionpack (5.2.0) lib/action_controller/metal.rb:191:in `dispatch'
actionpack (5.2.0) lib/action_controller/metal.rb:252:in `dispatch'
actionpack (5.2.0) lib/action_dispatch/routing/route_set.rb:52:in `dispatch'
actionpack (5.2.0) lib/action_dispatch/routing/route_set.rb:34:in `serve'
actionpack (5.2.0) lib/action_dispatch/journey/router.rb:52:in `block in serve'
actionpack (5.2.0) lib/action_dispatch/journey/router.rb:35:in `each'
actionpack (5.2.0) lib/action_dispatch/journey/router.rb:35:in `serve'
actionpack (5.2.0) lib/action_dispatch/routing/route_set.rb:840:in `call'
omniauth (1.8.1) lib/omniauth/strategy.rb:190:in `call!'
omniauth (1.8.1) lib/omniauth/strategy.rb:168:in `call'
warden (1.2.7) lib/warden/manager.rb:36:in `block in call'
warden (1.2.7) lib/warden/manager.rb:35:in `catch'
warden (1.2.7) lib/warden/manager.rb:35:in `call'
rack (2.0.5) lib/rack/tempfile_reaper.rb:15:in `call'
rack (2.0.5) lib/rack/etag.rb:25:in `call'
rack (2.0.5) lib/rack/conditional_get.rb:38:in `call'
rack (2.0.5) lib/rack/head.rb:12:in `call'
actionpack (5.2.0) lib/action_dispatch/http/content_security_policy.rb:18:in `call'
rack (2.0.5) lib/rack/session/abstract/id.rb:232:in `context'
rack (2.0.5) lib/rack/session/abstract/id.rb:226:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/cookies.rb:670:in `call'
activerecord (5.2.0) lib/active_record/migration.rb:559:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (5.2.0) lib/active_support/callbacks.rb:98:in `run_callbacks'
actionpack (5.2.0) lib/action_dispatch/middleware/callbacks.rb:26:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/executor.rb:14:in `call'
better_errors (2.4.0) lib/better_errors/middleware.rb:59:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/debug_exceptions.rb:61:in `call'
web-console (3.6.2) lib/web_console/middleware.rb:135:in `call_app'
web-console (3.6.2) lib/web_console/middleware.rb:22:in `block in call'
web-console (3.6.2) lib/web_console/middleware.rb:20:in `catch'
web-console (3.6.2) lib/web_console/middleware.rb:20:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
railties (5.2.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (5.2.0) lib/rails/rack/logger.rb:26:in `block in call'
activesupport (5.2.0) lib/active_support/tagged_logging.rb:71:in `block in tagged'
activesupport (5.2.0) lib/active_support/tagged_logging.rb:28:in `tagged'
activesupport (5.2.0) lib/active_support/tagged_logging.rb:71:in `tagged'
railties (5.2.0) lib/rails/rack/logger.rb:26:in `call'
sprockets-rails (3.2.1) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
request_store (1.4.1) lib/request_store/middleware.rb:19:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/request_id.rb:27:in `call'
rack (2.0.5) lib/rack/method_override.rb:22:in `call'
rack (2.0.5) lib/rack/runtime.rb:22:in `call'
activesupport (5.2.0) lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (5.2.0) lib/action_dispatch/middleware/static.rb:127:in `call'
rack (2.0.5) lib/rack/sendfile.rb:111:in `call'
railties (5.2.0) lib/rails/engine.rb:524:in `call'
puma (3.11.4) lib/puma/configuration.rb:225:in `call'
puma (3.11.4) lib/puma/server.rb:632:in `handle_request'
puma (3.11.4) lib/puma/server.rb:446:in `process_client'
puma (3.11.4) lib/puma/server.rb:306:in `block in run'
puma (3.11.4) lib/puma/thread_pool.rb:120:in `block in spawn_thread'
Request
Parameters:
{"utf8"=>"✓", "authenticity_token"=>"+KJueLU14yKJPxcTyhPbg0cQFkShT0oYjl9ddJR2pGKSDroJTReEMw7zukg3mpB5Gf3O8HhGYHDbYYqtNoM6Pw==",
 "city_review"=>
  {"title"=>"Blah Blah Blah",
   "score"=>"3",
   "love_list"=>"Schools / Education, Night Life, ",
   "improve_list"=>"Schools / Education, Taxes, ",
   "description"=>
    "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium.\r\n" +
    "Proin varius tincidunt purus, congue hendrerit ex interdum sed. Sed interdum, nibh ac lacinia vulputate, neque tellus ultricies nibh, eget vehicula ligula diam sit amet diam. Donec aliquam blandit laoreet. Cras at efficitur est. Phasellus quis enim vitae nisl sodales feugiat non sit amet tellus. Phasellus commodo, risus vitae luctus porta, nulla leo luctus massa, vel tempus odio tellus at nulla. Ut dictum nibh urna, quis scelerisque odio pellentesque ut. Sed at pretium nisi. Maecenas facilisis enim sed molestie gravida."},
 "commit"=>"Submit Review",
 "city_id"=>"lakewood"}

在我的服务器终端中，我收到 500 错误：

“在 13 毫秒内完成 500 内部服务器错误（ActiveRecord：1.5 毫秒）”

在 Rails 控制台中，我收到同样的错误。我的控制器发布在下面：

class CityReviewsController < ApplicationController
# Main controller for City Reviews
  before_action :set_city_review, only: [:show, :edit, :update, :destroy, :upvote]
  # Below - Sets City for method actions of City Review.
  before_action :set_city, except: [:edit, :update, :destroy] 
  # Below - Multiples the score value that is initially 1 out of 5 and factors it by 20.
  before_action :multiply_score, only: [:create, :update]
  # Below - Sets user related params and IDs 
  before_action :set_user_params, only: [:edit, :update, :destroy]

  def show
    # Below - adds punch counter to City Review.
    @city_review.punch(request)
    @city_review_comments = @city_review.comments
  end

  # GET /city_reviews/new
  def new
    @new_city_review = CityReview.new
  end

  # GET /city_reviews/1/edit
  def edit
    # Calls all user related params and ids from a before action above.

  end

  def create
    # Below -  Creates a WUL City Review for the city using the "city_review_params" method in "private" below, passing
      # attributes for the :title, :score, :description, :city_review_score_id, :user_id, and :city_id, taggings list (:love_list, :improve_list) and assigning the Review to the city.
    @new_city_review = @city.city_reviews.build(city_review_params)
    # Below - Sets the user id to the current user posting the city review
    @new_city_review.user_id = current_user.id 
    # Below - Sets the City Review ID to the current users city's ID.
    @new_city_review.city_id = current_user.city.id
    # Below - Sets the City Review Score Id to the associated city id which should match the City Score ID column.
    @new_city_review.city_review_score_id = current_user.city.id
    # Begin - If statement for determining if the City Review was committed to the DB successfully, then rendering the City Reviews 
      # show page with a success message, or displaying an error and rendering a new form page.
    if @new_city_review.save # If it saves, display Flash message success, if not move to 'else'
      flash[:notice] = "Your What You Love review for #{@city.name} has been successfully posted!"   # Shows a Flash message of success
      redirect_to city_review_path(@city, @new_city_review)  # Redirects to the City Review's show page.
    else
      flash[:alert] = "Could not post your What You Love review for #{@city.name}. See why below!"   # Shows a Flash message of error
      render 'new' # Reload the New template with errors
    end # End - If statement for review creation.
  end

  def update
    # Calls all user related params and ids from a before action above.
    @city_review.user_id = current_user.id 
    # Below - Sets the City Review ID to the current users city's ID.
    @city_review.city_id = current_user.city.id
    # Below - Sets the City Review Score Id to the associated city id which should match the City Score ID column.
    @city_review.city_review_score_id = current_user.city.id

    if @city_review.update(city_review_params)
      flash[:notice] = "Your What You Love Review has been updated successfully!"
      redirect_to city_review_path(@city, @city_review)
    else 
      flash[:alert] = "Your What You Love Review could not be updated. See why below!"
      render 'edit'
    end 
  end

  def destroy
    # Calls all user related params and ids from a before action above.
    if @city_review.user === current_user
      if @city_review.destroy
        flash[:alert] = "Your What You Love review has been deleted."
        redirect_to city_review_index_path(@city)
      end
    end
  end

  private
    # Below - Finds the City Review ID from the params
    def set_city_review
      @city_review = CityReview.friendly.find(params[:id])
    end
    # Below - Sets up the city for City Review
    def set_city
      @city = City.friendly.find(params[:city_id])
    end

    def city_review_params
      params.require(:city_review).permit(:id, :title, :description, :score, :user_id, :city_id, :city_review_score_id, :love_list, :improve_list)
    end

    # Below - Sets up user related params on edit, update and destroy.
    def set_user_params 
      @user = User.friendly.find(params[:user_id])
      @city_review = CityReview.friendly.find(params[:id])
      @city = @city_review.city.friendly_id
      @city_review_edit = @city_review
    end 
    # Takes the user submitted Score value (1..1.5..) out of 5, empties the existing params (:score),
      # multiplies it by 20 to get a percentage value out of 100, and reassigns the params to the newly
        # multiplied value.
    def multiply_score
      user_score = params[:city_review].delete(:score).to_f
      score = user_score * 20
      params[:city_review][:score] = score
    end
end

我的 ActsAsTaggableOn 相关模型代码：

   acts_as_taggable_on :love, :improve

根据 ActsAsTaggableOn gem 的建议，我通过运行以下命令使用了他们的迁移设置：

rakeacts_as_taggable_on_engine:install:migrations

这就是我的架构如何查找这些表：

 create_table "taggings", id: :serial, force: :cascade do |t|
    t.integer "tag_id"
    t.string "taggable_type"
    t.integer "taggable_id"
    t.string "tagger_type"
    t.integer "tagger_id"
    t.string "context", limit: 128
    t.datetime "created_at"
    t.index ["context"], name: "index_taggings_on_context"
    t.index ["tag_id", "taggable_id", "taggable_type", "context", "tagger_id", "tagger_type"], name: "taggings_idx", unique: true
    t.index ["tag_id"], name: "index_taggings_on_tag_id"
    t.index ["taggable_id", "taggable_type", "context"], name: "index_taggings_on_taggable_id_and_taggable_type_and_context"
    t.index ["taggable_id", "taggable_type", "tagger_id", "context"], name: "taggings_idy"
    t.index ["taggable_id"], name: "index_taggings_on_taggable_id"
    t.index ["taggable_type"], name: "index_taggings_on_taggable_type"
    t.index ["tagger_id", "tagger_type"], name: "index_taggings_on_tagger_id_and_tagger_type"
    t.index ["tagger_id"], name: "index_taggings_on_tagger_id"
  end

  create_table "tags", id: :serial, force: :cascade do |t|
    t.string "name"
    t.integer "taggings_count", default: 0
    t.index ["name"], name: "index_tags_on_name", unique: true
  end

为了解决这个问题，我尝试了很多不同的方法，例如回滚迁移、重新安装 gem、更改列表的名称、使用默认值、在不同的模型上使用它以及一些不同的控制器行动。此外，在代码中，您还会看到 FriendlyID Gem 的存在。

非常感谢您的阅读和您的帮助。

*要在 Rails 5.2 中临时修复这个 ActsAsTaggableOn 问题，请使用 Fodoj 的一个名为 rails-5.2 的分支。在您的 gemfile 中添加 git 链接和分支到作为可标记的 gem，然后运行 ​​bundle install 并重新启动您的服务器：*

gem 'acts-as-taggable-on', :git => 'https://github.com/Fodoj/acts-as-taggable-on', :branch => 'rails-5.2'

Answer 1

这里有一个开放的issue，还有一个开放的PR。请解决这些问题

您可以使用这些分支中的 gem（或者）您可以拥有自己的 fork 并修复此问题。