validates_uniqueness_of behaves well with abstract superclasses. References #3833, closes #9886.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8000 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 15 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/validations.rb b/activerecord/lib/active_record/validations.rb
index 6514c4077a..35a1f8d0d4 100755
--- a/activerecord/lib/active_record/validations.rb
+++ b/activerecord/lib/active_record/validations.rb
@@ -633,7 +633,21 @@ module ActiveRecord
             condition_params << record.send(:id)
           end
 
-          if find(:first, :conditions => [condition_sql, *condition_params])
+          # The check for an existing value should be run from a class that
+          # isn't abstract. This means working down from the current class
+          # (self), to the first non-abstract class. Since classes don't know
+          # their subclasses, we have to build the hierarchy between self and
+          # the record's class.
+          class_hierarchy = [record.class]
+          while class_hierarchy.first != self
+            class_hierarchy.insert(0, class_hierarchy.first.superclass)
+          end
+
+          # Now we can work our way down the tree to the first non-abstract
+          # class (which has a database table to query from).
+          finder_class = class_hierarchy.detect { |klass| !klass.abstract_class? }
+
+          if finder_class.find(:first, :conditions => [condition_sql, *condition_params])
             record.errors.add(attr_name, configuration[:message])
           end
         end