未定義的方法`地圖'爲零：NilClass太陽黑子has_one協會

Question

我有一個表用戶，其中有一個common_app。我想在用戶的common_app.cover_letter中創建可搜索的文本。

當我嘗試這樣做，我得到的錯誤 -

rake sunspot:reindex 
undefined method `map' for nil:NilClass 
/Users/stepan/Desktop/Previous Desktop/Sites/atlas/app/models/user.rb:45:in `block (2 levels) in <class:User>' 

這是我的用戶模型看起來像 -

# == Schema Information 
# 
# Table name: users 
# 
# id      :integer   not null, primary key 
# name     :string(255) 
# email     :string(255) 
# created_at    :datetime 
# updated_at    :datetime 
# password_digest  :string(255) 
# remember_token   :string(255) 
# admin     :boolean   default(FALSE) 
# password_reset_token :string(255) 
# password_reset_sent_at :datetime 
# heat_id    :integer 
# 

class User < ActiveRecord::Base 
    before_save { self.email = email.downcase } 
    before_create :create_remember_token 

    validates :name, presence: true, length: { maximum: 50 } 
    VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i 
    validates :email, presence: true, 
      format: { with: VALID_EMAIL_REGEX }, 
      uniqueness: { case_sensitive: false } 

    has_secure_password validations: false 

    validates :password, length: { minimum: 6 }, allow_blank: true 
    validates :password, presence: true, on: :create 

    belongs_to :heat 

    has_one :common_app, dependent: :destroy 

    has_one :video, dependent: :destroy 

    has_many :applications, dependent: :destroy 
    has_many :jobs, :through => :applications 

    searchable do 
    text :name, :email 
    text :common_app do 
     common_app.map { |common_app| common_app.cover_letter } 
    end 
    end 

    def User.new_remember_token 
    SecureRandom.urlsafe_base64 
    end 

    def User.encrypt(token) 
    Digest::SHA1.hexdigest(token.to_s) 
    end 

    def send_password_reset 
    generate_token(:password_reset_token) 
    self.password_reset_sent_at = Time.zone.now 
    save! 
    UserMailer.password_reset(self).deliver 
    end 

    def generate_token(column) # this is similar to create_remember_token, but instead it's generalized, so it can work on any column 
    begin 
     self[column] = SecureRandom.urlsafe_base64 
    end while User.exists?(column => self[column]) 
    end 

    def beginner? 
    false if self.common_app || self.video || self.jobs.any? 
    end 

    def first_name 
    self.name.split(' ')[0].capitalize 
    end 

    private 

    def create_remember_token 
     self.remember_token = User.encrypt(User.new_remember_token) 
    end 

end 

我猜這種情況正在發生，因爲一些用戶沒有common_app，或者我錯誤地引用了has_one關聯。

非常感謝！

Answer 1

我認爲這應該工作。

text :common_app do 
    common_app.cover_letter 
    end 

這是一個has_one關係，這意味着你不能映射它。如果它是has_many :common_apps關係，則可以映射。