Cater for DST changes when converting Times to DateTimes. Closes #10068 [gbuesing]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8076 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 13 insertions, 4 deletions

diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index b672ada7b9..2e85d14579 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -5,6 +5,16 @@ module ActiveSupport #:nodoc:
     module DateTime #:nodoc:
       # Enables the use of time calculations within DateTime itself
       module Calculations
+        def self.included(base) #:nodoc:
+          base.extend ClassMethods
+        end
+
+        module ClassMethods
+          # DateTimes aren't aware of DST rules, so use a consistent non-DST offset when creating a DateTime with an offset in the local zone
+          def local_offset
+            ::Time.local(2007).utc_offset.to_r / 86400
+          end
+        end
 
         # Seconds since midnight: DateTime.now.seconds_since_midnight
         def seconds_since_midnight
diff --git a/activesupport/lib/active_support/core_ext/date_time/conversions.rb b/activesupport/lib/active_support/core_ext/date_time/conversions.rb
index 776f1806f9..45d09f344d 100644
--- a/activesupport/lib/active_support/core_ext/date_time/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/conversions.rb
@@ -35,10 +35,9 @@ module ActiveSupport #:nodoc:
         end
 
         # Attempts to convert self to a Ruby Time object; returns self if out of range of Ruby Time class
-        # If self.offset is 0, then will attempt to cast as a utc time; otherwise will attempt to cast in local time zone
+        # If self has an offset other than 0, self will just be returned unaltered, since there's no clean way to map it to a Time
         def to_time
-          method = if self.offset == 0 then 'utc' else 'local' end
-          ::Time.send(method, year, month, day, hour, min, sec) rescue self
+          self.offset == 0 ? ::Time.utc_time(year, month, day, hour, min, sec) : self
         end        
 
         # To be able to keep Times, Dates and DateTimes interchangeable on conversions
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index 7f449aee49..19ac8f5a36 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -35,7 +35,7 @@ module ActiveSupport #:nodoc:
           def time_with_datetime_fallback(utc_or_local, year, month=1, day=1, hour=0, min=0, sec=0, usec=0)
             ::Time.send(utc_or_local, year, month, day, hour, min, sec, usec)
           rescue
-            offset = if utc_or_local.to_sym == :utc then 0 else ::DateTime.now.offset end
+            offset = utc_or_local.to_sym == :local ? ::DateTime.local_offset : 0
             ::DateTime.civil(year, month, day, hour, min, sec, offset, 0)
           end