Adding Time and DateTime #compare_with_coercion, which layers behavior on #<=> so that any combination of Time, DateTime and ActiveSupport::TimeWithZone instances can be chronologically compared

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8711 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 29 insertions, 1 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 d93c1148c4..5c351c21c6 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -7,6 +7,11 @@ module ActiveSupport #:nodoc:
       module Calculations
         def self.included(base) #:nodoc:
           base.extend ClassMethods
+          
+          base.class_eval do
+            alias_method :compare_without_coercion, :<=>
+            alias_method :<=>, :compare_with_coercion
+          end
         end
 
         module ClassMethods
@@ -91,6 +96,13 @@ module ActiveSupport #:nodoc:
         def utc_offset
           (offset * 86400).to_i
         end
+        
+        # Layers additional behavior on DateTime#<=> so that Time and ActiveSupport::TimeWithZone instances can be compared with a DateTime
+        def compare_with_coercion(other)
+          other = other.comparable_time if other.respond_to?(:comparable_time)
+          other = other.to_datetime unless other.acts_like?(:date)
+          compare_without_coercion(other)
+        end
       end
     end
   end
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index 7181bac3fd..534571fe61 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -9,8 +9,12 @@ module ActiveSupport #:nodoc:
           base.class_eval do
             alias_method :plus_without_duration, :+
             alias_method :+, :plus_with_duration
+            
             alias_method :minus_without_duration, :-
             alias_method :-, :minus_with_duration
+            
+            alias_method :compare_without_coercion, :<=>
+            alias_method :<=>, :compare_with_coercion
           end
         end
 
@@ -218,6 +222,19 @@ module ActiveSupport #:nodoc:
             minus_without_duration(other)
           end
         end
+        
+        # Layers additional behavior on Time#<=> so that DateTime and ActiveSupport::TimeWithZone instances
+        # can be chronologically compared with a Time
+        def compare_with_coercion(other)
+          # if other is an ActiveSupport::TimeWithZone, coerce a Time instance from it so we can do <=> comparision
+          other = other.comparable_time if other.respond_to?(:comparable_time)
+          if other.acts_like?(:date)
+            # other is a Date/DateTime, so coerce self #to_datetime and hand off to DateTime#<=>
+            to_datetime.compare_without_coercion(other)
+          else
+            compare_without_coercion(other)
+          end
+        end
       end
     end
   end
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index dcd55ae93d..648fa16f4e 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -105,7 +105,6 @@ module ActiveSupport
   
     # Use the time in UTC for comparisons
     def <=>(other)
-      other = other.comparable_time if other.respond_to?(:comparable_time) # to coerce time from TimeWithZone
       utc <=> other
     end