1 files changed, 26 insertions, 8 deletions
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index 008c7f151b..68585e8273 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -5,29 +5,28 @@ module ActiveSupport
     include Comparable
     attr_reader :time_zone
   
-    def initialize(utc_time, time_zone, local_time = nil)
-      @utc = utc_time
-      @time = local_time
-      @time_zone = time_zone
+    def initialize(utc_time, time_zone, local_time = nil, period = nil)
+      @utc, @time_zone, @time = utc_time, time_zone, local_time
+      @period = @utc ? period : get_period_and_ensure_valid_local_time
     end
   
     # Returns a Time instance that represents the time in time_zone
     def time
-      @time ||= time_zone.utc_to_local(@utc)
+      @time ||= utc_to_local
     end
 
     # Returns a Time instance that represents the time in UTC
     def utc
-      @utc ||= time_zone.local_to_utc(@time)
+      @utc ||= local_to_utc
     end
     alias_method :comparable_time, :utc
     alias_method :getgm, :utc
     alias_method :getutc, :utc
     alias_method :gmtime, :utc
   
-    # Returns the underlying TZInfo::TimezonePeriod for the local time
+    # Returns the underlying TZInfo::TimezonePeriod
     def period
-      @period ||= time_zone.period_for_utc(utc)
+      @period ||= time_zone.period_for_utc(@utc)
     end
 
     # Returns the simultaneous time in the specified zone
@@ -214,5 +213,24 @@ module ActiveSupport
       result = result.in_time_zone(time_zone) if result.acts_like?(:time)
       result
     end
+    
+    private      
+      def get_period_and_ensure_valid_local_time
+        @time_zone.period_for_local(@time)
+      rescue ::TZInfo::PeriodNotFound
+        # time is in the "spring forward" hour gap, so we're moving the time forward one hour and trying again
+        @time += 1.hour
+        retry
+      end
+    
+      # Replicating logic from TZInfo::Timezone#utc_to_local because we want to cache the period in an instance variable for reuse
+      def utc_to_local
+        ::TZInfo::TimeOrDateTime.wrap(utc) {|utc| period.to_local(utc)}
+      end
+      
+      # Replicating logic from TZInfo::Timezone#local_to_utc because we want to cache the period in an instance variable for reuse
+      def local_to_utc
+        ::TZInfo::TimeOrDateTime.wrap(time) {|time| period.to_utc(time)}
+      end
   end
 end