1 files changed, 15 insertions, 3 deletions
diff --git a/activemodel/lib/active_model/validations/inclusion.rb b/activemodel/lib/active_model/validations/inclusion.rb
index 049b093618..92ac940f36 100644
--- a/activemodel/lib/active_model/validations/inclusion.rb
+++ b/activemodel/lib/active_model/validations/inclusion.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/range.rb'
+
 module ActiveModel
 
   # == Active Model Inclusion Validator
@@ -9,9 +11,14 @@ module ActiveModel
       end
 
       def validate_each(record, attribute, value)
-        unless options[:in].include?(value)
-          record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value))
-        end
+        record.errors.add(attribute, :inclusion, options.except(:in).merge!(:value => value)) unless options[:in].send(include?, value)
+      end
+
+      # In Ruby 1.9 <tt>Range#include?</tt> on non-numeric ranges checks all possible values in the
+      # range for equality, so it may be slow for large ranges. The new <tt>Range#cover?</tt>
+      # uses the previous logic of comparing a value with the range endpoints.
+      def include?
+        options[:in].is_a?(Range) ? :cover? : :include?
       end
     end
 
@@ -26,9 +33,14 @@ module ActiveModel
       #
       # Configuration options:
       # * <tt>:in</tt> - An enumerable object of available items.
+      #   If the enumerable is a range the test is performed with <tt>Range#cover?</tt>
+      #   (backported in Active Support for 1.8), otherwise with <tt>include?</tt>.
       # * <tt>:message</tt> - Specifies a custom error message (default is: "is not included in the list").
       # * <tt>:allow_nil</tt> - If set to true, skips this validation if the attribute is +nil+ (default is +false+).
       # * <tt>:allow_blank</tt> - If set to true, skips this validation if the attribute is blank (default is +false+).
+      # * <tt>:on</tt> - Specifies when this validation is active. Runs in all
+      #   validation contexts by default (+nil+), other options are <tt>:create</tt>
+      #   and <tt>:update</tt>.
       # * <tt>:if</tt> - Specifies a method, proc or string to call to determine if the validation should
       #   occur (e.g. <tt>:if => :allow_validation</tt>, or <tt>:if => Proc.new { |user| user.signup_step > 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.