1 files changed, 9 insertions, 3 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 289ca12b5e..95617fb8c2 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -10,7 +10,11 @@ class DateTime
     end
   end
 
-  # Seconds since midnight: DateTime.now.seconds_since_midnight.
+  # Returns the number of seconds since 00:00:00.
+  #
+  #   DateTime.new(2012, 8, 29,  0,  0,  0).seconds_since_midnight # => 0
+  #   DateTime.new(2012, 8, 29, 12, 34, 56).seconds_since_midnight # => 45296
+  #   DateTime.new(2012, 8, 29, 23, 59, 59).seconds_since_midnight # => 86399
   def seconds_since_midnight
     sec + (min * 60) + (hour * 3600)
   end
@@ -161,8 +165,10 @@ class DateTime
   # Layers additional behavior on DateTime#<=> so that Time and
   # ActiveSupport::TimeWithZone instances can be compared with a DateTime.
   def <=>(other)
-    if other.respond_to? :to_datetime
-      super other.to_datetime
+    if other.kind_of?(Infinity)
+      super
+    elsif other.respond_to? :to_datetime
+      super other.to_datetime rescue nil
     else
       nil
     end