1 files changed, 20 insertions, 3 deletions
diff --git a/activemodel/lib/active_model/validations/inclusion.rb b/activemodel/lib/active_model/validations/inclusion.rb
index 049b093618..108586b8df 100644
--- a/activemodel/lib/active_model/validations/inclusion.rb
+++ b/activemodel/lib/active_model/validations/inclusion.rb
@@ -8,9 +8,26 @@ module ActiveModel
                               ":in option of the configuration hash" unless options[:in].respond_to?(:include?)
       end
 
-      def validate_each(record, attribute, value)
-        unless options[:in].include?(value)
-          record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
+      # On Ruby 1.9 Range#include? checks all possible values in the range for equality,
+      # so it may be slow for large ranges. The new Range#cover? uses the previous logic
+      # of comparing a value with the range endpoints.
+      if (1..2).respond_to?(:cover?)
+        def validate_each(record, attribute, value)
+          included = if options[:in].is_a?(Range)
+            options[:in].cover?(value)
+          else
+            options[:in].include?(value)
+          end
+
+          unless included
+            record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
+          end
+        end
+      else
+        def validate_each(record, attribute, value)
+          unless options[:in].include?(value)
+            record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
+          end
         end
       end
     end