title: Rails getting validation failed error, but no errors in ActiveRecord error model
body: <p>I am having a problem with validation errors when saving a model using save!. The ActiveRecord error model error messages are blank, so i dont know what errors are happening on a validation attempt. When I try errors.full_messages or errors.each_full according to the <a href="http://ar.rubyonrails.org/classes/ActiveRecord/Errors.html">documentation</a>, it should display the errors, which it doesn't.</p>
  
  <p>The model I am trying to save is the Orders model (ecommerce site using Spree). When an item in the order gets deleted, update_totals! gets called which recalculates the totals, and then save! is called, which triggers the validation error (<strong>this error happens very rarely but only when I'm logged in</strong>, and I havent been able to find the cause of it). The order model has two validations in its model:</p>
  
  <pre><code>  validates_numericality_of :item_total
    validates_numericality_of :total
  </code></pre>
  
  <p>i recorded order.item_total.inspect, order.total.inspect, and order.errors.full_messages.inspect and got this:</p>
  
  <pre><code>Wed Jan 25 08:53:08 -0800 2012order item total: #&lt;BigDecimal:15780c60,'0.279E2',8(16)&gt;
  Wed Jan 25 08:53:08 -0800 2012order total: #&lt;BigDecimal:152bf410,'0.2448225E2',12(20)&gt;
  Wed Jan 25 08:53:08 -0800 2012: ERRORS SAVING ORDER: 
  Wed Jan 25 08:53:08 -0800 2012[]
  </code></pre>
  
  <p>item_total and total are stored in the mySQL database as decimal(8,2). The last line is order.errors.full_messages.inspect, which is an empty array. The validation error looks like this:</p>
  
  <pre><code>ActiveRecord::RecordInvalid (Validation failed: {{errors}}):
    vendor/extensions/mgx_core/app/models/order.rb:382:in `update_totals!'
    vendor/extensions/mgx_core/app/controllers/line_items_controller.rb:7:in `destroy'
    app/middleware/flash_session_cookie_middleware.rb:19:in `call'
    C:\Users\mgx\My Documents\Aptana Studio 3 Workspace\catalogue-spree\script\server:3
    c:/Ruby187/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.16/lib/ruby-debug-ide.rb:112:in `debug_load'
    c:/Ruby187/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.16/lib/ruby-debug-ide.rb:112:in `debug_program'
    c:/Ruby187/lib/ruby/gems/1.8/gems/ruby-debug-ide-0.4.16/bin/rdebug-ide:87
    c:/Ruby187/bin/rdebug-ide:19:in `load'
    c:/Ruby187/bin/rdebug-ide:19
  </code></pre>
  
  <p><strong>I guess my question is twofold:</strong></p>
  
  <p><strong>1. Why is my activerecord errors model not saying what the validation error is?</strong></p>
  
  <p><strong>2. How do I fix this problem? Is my item_total and total valid for saving as decimal(8,2)?</strong></p>
  
  <p>I am using rails 2.3.5 and spree 0.10.2</p>