Time Zones say WHA?

gistfile1.txt

$ rails -v
Rails 3.2.8
$ rails c
Loading development environment (Rails 3.2.8)
1.9.3-p194 :001 > Time.zone = 'Paris'
 => "Paris" 
1.9.3-p194 :002 > t = Time.zone
 => (GMT+01:00) Paris # HUH?  Paris is GMT+02:00 right now, thanks to DST

Now deep in the bowels of ActiveSupport::TimeZone, we have the following:

def utc_offset                                                              
  if @utc_offset                                                            
    @utc_offset                                                             
  else                                                                      
    @current_period ||= tzinfo.try(:current_period)                         
    @current_period.try(:utc_offset)                                        
  end                                                                       
end

Now, TZInfo has a fancy method called utc_total_offset that, according to the docs, does the following:
utc_total_offset() - Total offset from UTC (seconds). Equal to utc_offset + std_offset.

A HA!  std_offset?  As in, an offset that's added to the utc_offset when a time zone is in DST?

When we patch this ActiveSupport method to use utc_total_offset instead of the dumber utc_offset, we get the following:

$ rails c
Loading development environment (Rails 3.2.8)
1.9.3-p194 :001 > Time.zone = 'Paris'
 => "Paris" 
1.9.3-p194 :002 > t = Time.zone
 => (GMT+02:00) Paris # HUZZAH!!!!

You're exactly right :).

The calculations are correct - it's purely a display issue. But it's a pretty lousy one - in our time zone picker, the value you select is Paris (GMT+01:00) but Rails saves any datetime in that timezone as GMT+2 :/