ruby-on-rails – 无法序列化为ActiveSupport :: HashWithIndiff

模型的相关部分如下所示：

class Item < ActiveRecord::Base
  serialize :metadata,ActiveSupport::HashWithIndifferentAccess

(我添加了尝试强制它的选项,但它没有帮助.以前这一切都工作正常,我没有那里.)

只要对象在内存中,一切正常.这是正确的HashWithIndifferentAccess,生活是美好的.一旦它被保存到数据库,它就会被保存为Hash：

mysql> select * from items;
+----+------+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+
| id | link | text        | metadata                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | category_id |
+----+------+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+
|  1 | NULL | Apple Store | ---
id: 42cc7080f964a520e9251fe3
name: Apple Store
contact:
  phone: '4153920202'
  formattedPhone: (415) 392-0202
location:
  address: 1 Stockton St.
  crossStreet: at Ellis St.
  lat: '37.78573590563453'
  lng: '-122.40610713227913'
  distance: '1784'
  postalCode: '94108'
  city: San Francisco
  state: CA
  country: USA
categories:
  '0':
    id: 4bf58dd8d48988d122951735
    name: Electronics Store
    pluralName: Electronics Stores
    shortName: Electronics
    icon: https://foursquare.com/img/categories/shops/technology.png
    parents:
    - Shops & Services
    primary: 'true'
verified: 'false'
stats:
  checkinsCount: '30462'
  usersCount: '16105'
  tipCount: '128'
url: http://apple.com/sanfrancisco
hereNow:
  count: '7'
 | 1           |
+----+------+-------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+

这意味着它不能被强制回HashWithIndifferentAccess并且事情就像这样爆炸了：

ActiveRecord::SerializationTypeMismatch in Index#index

Showing /development/lists.io/website/app/views/users/_todo.html.haml where line #7 raised:

Attribute was supposed to be a ActiveSupport::HashWithIndifferentAccess,but was a Hash

这是使用Rails 3.1.3,使用mysql2 gem版本0.3.10将数据存储在MySQL中.我也在运行ruby 1.9.2p290.我可以添加任何人认为有用的信息,但我不知道如何进一步调试.