Invalid: dirty AR attributes should be retained if save fails

When saving a record, AR (via the Dirty module) will clear all dirty attributes regardless of the result of the save operation. It would make more sense if these attributes were only cleared upon a successful save. This way, if a save operation fails any helper functions can still tell if a value is dirty after Rails falls back through to the edit/create page.

Here's an example using the console

>> p = Project.new
=> #<Project:0x4735d6c>
>> p.changed
=> []
>> p.id = 1
=> 1
>> p.changed
=> ["id"]
>> p.save
=> false
>> p.changed
=> []