自动加载常量时检测到循环依赖(Rails 4，Ruby 2) [英] Circular dependency detected while autoloading constant (Rails 4, Ruby 2)

问题描述

configs/routes.rb Shutters和Paints是Jobs的子资源.

resources :jobs do
    resources :shutters
    resources :paints
end

app/models/job.rb Job包含许多Shutters和许多Paints.

class Job < ActiveRecord::Base
    has_many :shutters, dependent: :delete_all
    has_many :paints, dependent: :delete_all

    accepts_nested_attributes_for :shutters, allow_destroy: true, :reject_if => lambda { |a| a[:no].blank? }
    accepts_nested_attributes_for :paints, allow_destroy: true, :reject_if => lambda { |a| a[:name].blank? }`

app/models/shutter.rb 一个Shutter包含属于一个Job和一个Paint.

app/models/shutter.rb A Shutter contains belongs to one Job and one Paint.

class Shutter < ActiveRecord::Base
    belongs_to :job
    belongs_to :paint

app/models/paint.rb 一个Paint属于一个Job，但是在该作业中可以被许多Shutters引用.

app/models/paint.rb A Paint belongs to one Job but can be referenced by many Shutters in that job.

class Paint < ActiveRecord::Base
    belongs_to :job
    has_many :shutters

如果数据库中没有Paints，则和Jobs#edit都可以与代码<%= debug @job.paints %>一起正常工作.但是，一旦添加涂料，就会引发RuntimeError，在自动加载常量PAINT时检测到循环依赖".

Both Jobs#show and Jobs#edit work fine with the code <%= debug @job.paints %> if there are no Paints already in the database. But the moment a paint is added, a RuntimeError is raised, "Circular dependency detected while autoloading constant PAINT".

解决此错误的最佳方法是什么?

What's the best way to fix this error?

控制器信息

app/controllers/jobs_controller.rb

class JobsController < ApplicationController
    before_action :set_job, only: [:show, :edit, :update, :destroy]

    ...

    # GET /jobs/1
    # GET /jobs/1.json
    def show
    end

    # GET /jobs/new
    def new
        @job = Job.new
        @job.shutters.build
        @job.paints.build
    end

    # GET /jobs/1/edit
    def edit
        @job.shutters.build
        @job.paints.build
    end

app/controllers/shutters_controller.rb

class ShuttersController < ApplicationController
    def new
        @shutter = Shutter.new
    end

    def destroy
        @shutter = Shutter.find(params[:id])
        @job = Job.find(@shutter[:job_id])
        @shutter.destroy
        respond_to do |format|
            format.html {redirect_to @job, notice: 'Shutter was succesfully deleted.' }
        end
    end
end

app/controllers/paints_controller.rb

class PaintsController < ApplicationController
    def new
        @paint = Paint.new
    end

    def destroy
        @paint = Paint.find(params[:id])
        @job = Job.find(@paint[:job_id])
        @paint.destroy
        respond_to do |format|
            format.html {redirect_to @job, notice: 'Paint was succesfully deleted.' }
        end
    end
end

推荐答案

问题不是这些.实际上，我的Paint模型包含一个名为:type的字段，这是元分类或类似内容的保留关键字.幸好得到了#RubyOnRails同事的帮助，否则像我这样的新手将尝试从头开始，遇到相同的问题，并且永远都不会想到.希望这对将来的Googler有帮助.向前付款！

The problem was none of these. It was actually that my Paint model contained a field named :type, which is a reserved keyword for meta-classing or something as such. Was thankfully helped by the kind folks at #RubyOnRails, else a newbie like me would have tried to start from scratch, run into the same problem, and would have never have figured this out. Hopefully this helps some future Googler. Pay it forward!

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