Dirty datetime attributes lose time zone info

+1, this this has bitten me as well

I am having the same issue using dirty attributes to create a change log.

This is happening because when storing the old attributes on @changed_attributes hash the datetime attributes were being transformed from ActiveSupport::TimeWithZone to just Time:

irb(main):007:0> p.created_at.class
=> ActiveSupport::TimeWithZone
irb(main):009:0> p.created_at = Time.now
=> Thu Apr 08 00:59:46 -0400 2010
irb(main):011:0> p.created_at.class
=> ActiveSupport::TimeWithZone
irb(main):012:0> p.created_at_was.class
=> Time

The funny part is that is that ActiveSupport::TimeWithZone objects are created on-the-fly by the module ActiveRecord::AttributeMethods::TimeZoneConversion which overwrite read/write methods for datetime/timestamp columns when ActiveRecord::Base.time_zone_aware_attributes = true, so when cloning (ActiveRecord::Base.clone_attribute_value) datetime attributes it was getting the object Time and not ActiveSupport::TimeWithZone.

My approach on this patch is storing on @changed_attributes the actual ActiveSupport::TimeWithZone object when ActiveRecord::Base.time_zone_aware_attributes = true and the attribute is not on skip_time_zone_conversion_for_attributes hash.

I don't know if it's the right way to attack this issue, it's just a try.. :)

Ops, noticed that I broke one test by note keeping my time zone configurations inside my test scope. Attached another patch with tests written right.

gucci watches