1 files changed, 23 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/type/numeric.rb b/activerecord/lib/active_record/type/numeric.rb
index 464d631d80..9cc6411e77 100644
--- a/activerecord/lib/active_record/type/numeric.rb
+++ b/activerecord/lib/active_record/type/numeric.rb
@@ -13,6 +13,29 @@ module ActiveRecord
         else super
         end
       end
+
+      def changed?(old_value, new_value) # :nodoc:
+        # 0 => 'wibble' should mark as changed so numericality validations run
+        if nil_or_zero?(old_value) && non_numeric_string?(new_value)
+          # nil => '' should not mark as changed
+          old_value != new_value.presence
+        else
+          super
+        end
+      end
+
+      private
+
+      def non_numeric_string?(value)
+        # 'wibble'.to_i will give zero, we want to make sure
+        # that we aren't marking int zero to string zero as
+        # changed.
+        value !~ /\A\d+\.?\d*\z/
+      end
+
+      def nil_or_zero?(value)
+        value.nil? || value == 0
+      end
     end
   end
 end