1 files changed, 43 insertions, 3 deletions
diff --git a/activerecord/lib/active_record/type/integer.rb b/activerecord/lib/active_record/type/integer.rb
index 08477d1303..2a1b04ac7f 100644
--- a/activerecord/lib/active_record/type/integer.rb
+++ b/activerecord/lib/active_record/type/integer.rb
@@ -1,13 +1,37 @@
 module ActiveRecord
   module Type
     class Integer < Value # :nodoc:
-      include Numeric
+      include Helpers::Numeric
+
+      # Column storage size in bytes.
+      # 4 bytes means a MySQL int or Postgres integer as opposed to smallint etc.
+      DEFAULT_LIMIT = 4
+
+      def initialize(*)
+        super
+        @range = min_value...max_value
+      end
 
       def type
         :integer
       end
 
-      alias type_cast_for_database type_cast
+      def deserialize(value)
+        return if value.nil?
+        value.to_i
+      end
+
+      def serialize(value)
+        result = cast(value)
+        if result
+          ensure_in_range(result)
+        end
+        result
+      end
+
+      protected
+
+      attr_reader :range
 
       private
 
@@ -15,9 +39,25 @@ module ActiveRecord
         case value
         when true then 1
         when false then 0
-        else value.to_i rescue nil
+        else
+          value.to_i rescue nil
+        end
+      end
+
+      def ensure_in_range(value)
+        unless range.cover?(value)
+          raise RangeError, "#{value} is out of range for #{self.class} with limit #{limit || DEFAULT_LIMIT}"
         end
       end
+
+      def max_value
+        limit = self.limit || DEFAULT_LIMIT
+        1 << (limit * 8 - 1) # 8 bits per byte with one bit for sign
+      end
+
+      def min_value
+        -max_value
+      end
     end
   end
 end