提前感谢您的帮助。
下面，在我的帖子的底部，我更新了这个问题的修复程序，部分归功于Narasimha Reddy。希望它在升级到Rails 5.2之后帮助任何有类似问题的人。更新：ActsAsTaggableOn 6.0已经解决并解决了这个问题。
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，这个问题没有发生，从那以后只有上述变化。我使用ActsAsTaggableOn（5.0.0）gem作为使用两个列表的评论表单：love_list和improve_list。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13ms内完成500内部服务器错误（ActiveRecord：1.5ms）”
在Rails控制台中，我收到相同的错误。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
ActsAsTaggableOn的相关型号代码：
acts_as_taggable_on :love, :improve
根据ActsAsTaggableOn gem建议，我通过运行命令使用了他们的迁移设置：
rake acts_as_taggable_on_engine：install：migrations
这就是我的架构查找这些表的方式：
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东西，例如回滚迁移，重新安装gem，更改列表名称，使用默认值，在不同模型上使用它，以及一些不同的控制器动作。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帮助。
*要使用Rails 5.2临时修复此ActsAsTaggableOn问题，请使用Fodoj中名为rails-5.2的分支。在你的gemfile中添加git链接和分支到actions-as-taggable-on gem，然后运行 bundle install 并重启你的服务器：*
gem 'acts-as-taggable-on', :git => 'https://github.com/Fodoj/acts-as-taggable-on', :branch => 'rails-5.2'