Ruby on rails 3 Rails 3序列化属性验证错误：nil:NilClass的未定义方法“read\u attribute\u for\u validation”

当尝试将序列化属性与已定义的类一起使用时，Rails会很高兴，直到保存对象之后。我的ActiveRecord模型和使用ActiveModel:：validations的序列化对象中都有验证。作为验证的一部分，父模型检查以确保序列化对象有效？。我相信这是问题的核心，但我不确定它为什么会导致问题，也不确定解决问题的最佳方法

我已将问题简化为一个最小的rails项目：

密码 创建新的rails项目版本3.2.6并使用rails g model a数据创建a模型：文本I定义：

app/models/a.rb

测试/单元/a_测试.rb

所以@errors中的@base是nil，这就是nil:NilClass`的异常未定义的methodread\u属性\u中引用的nil

有人知道发生了什么吗？这是Rails bug吗？我做错什么了吗

---

谢谢

升级到ruby 1.9.3-p194修复了这个问题，我以前使用的是1.9.2-p290。相关github问题：

class A < ActiveRecord::Base
  attr_accessible :data
  serialize :data, B

  validate :custom

  def custom
    errors.add :data, "whoopsies!" unless data.valid?
  end
end

class B
  include ActiveModel::Validations
  attr_accessor :foo
  validates_presence_of :foo
end

require 'test_helper'

class ATest < ActiveSupport::TestCase
  test "weird failure" do
    a = A.new
    b = B.new
    b.foo = 'bar'
    a.data = b

    assert a.valid?
    assert b.valid?
    assert a.save

    assert a.valid? # -> throws exception
  end
end

NoMethodError: undefined method `read_attribute_for_validation' for nil:NilClass
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/errors.rb:254:in `block in add_on_blank'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/errors.rb:253:in `each'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/errors.rb:253:in `add_on_blank'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations/presence.rb:8:in `validate'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:310:in `_callback_before_7'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:407:in `_run__2107971919899649095__validate__2662006763039653414__callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:405:in `__run_callback'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:385:in `_run_validate_callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations.rb:226:in `run_validations!'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations.rb:193:in `valid?'
    /Users/gbelote/tmp/serialize-fail/app/models/a.rb:8:in `custom'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:407:in `_run__3204678033069886840__validate__2662006763039653414__callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:405:in `__run_callback'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:385:in `_run_validate_callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations.rb:226:in `run_validations!'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations/callbacks.rb:53:in `block in run_validations!'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:403:in `_run__3204678033069886840__validation__2662006763039653414__callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:405:in `__run_callback'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:385:in `_run_validation_callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activesupport-3.2.6/lib/active_support/callbacks.rb:81:in `run_callbacks'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations/callbacks.rb:53:in `run_validations!'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activemodel-3.2.6/lib/active_model/validations.rb:193:in `valid?'
    /Users/gbelote/.rvm/gems/ruby-1.9.2-p290@serialize-fail/gems/activerecord-3.2.6/lib/active_record/validations.rb:69:in `valid?'
    /Users/gbelote/tmp/serialize-fail/test/unit/a_test.rb:14:in `block in <class:ATest>'

before: #<B:0x0000010327e710 @foo="bar", @validation_context=nil, @errors=#<ActiveModel::Errors:0x0000010321b7a0 @base=#<B:0x0000010327e710 ...>, @messages={}>>
after:  #<B:0x00000103197158 @foo="bar", @validation_context=nil, @errors=#<ActiveModel::Errors:0x000001031965f0 @base=nil, @messages={}>>