fix `reset_counters` to work even with complex class names

e.g. it guesses that a belongs_to association to Namespace::MyModel is
named "my_model", unlike before where it would look up an association
named "namespace::mymodel" and fail.

activerecord/lib/active_record/counter_cache.rb

@@ -16,13 +16,15 @@ module CounterCache
     def reset_counters(id, *counters)
       object = find(id)
       counters.each do |association|
-        child_class = reflect_on_association(association).klass
-        counter_name = child_class.reflect_on_association(self.name.downcase.to_sym).counter_cache_column
+        child_class = reflect_on_association(association.to_sym).klass
+        belongs_name = self.name.demodulize.underscore.to_sym
+        counter_name = child_class.reflect_on_association(belongs_name).counter_cache_column
 
-        self.unscoped.where(arel_table[self.primary_key].eq(object.id)).arel.update(
+        self.unscoped.where(arel_table[self.primary_key].eq(object.id)).arel.update({
           arel_table[counter_name] => object.send(association).count
-        )
+        })
       end
+      return true
     end
 
     # A generic "counter updater" implementation, intended primarily to be

activerecord/test/cases/counter_cache_test.rb

@@ -7,6 +7,14 @@
 class CounterCacheTest < ActiveRecord::TestCase
   fixtures :topics, :categories, :categorizations
 
+  class SpecialTopic < ::Topic
+    has_many :special_replies, :foreign_key => 'parent_id'
+  end
+
+  class SpecialReply < ::Reply
+    belongs_to :special_topic, :foreign_key => 'parent_id', :counter_cache => 'replies_count'
+  end
+
   setup do
     @topic = Topic.find(1)
   end
@@ -32,6 +40,23 @@ class CounterCacheTest < ActiveRecord::TestCase
       Topic.reset_counters(@topic.id, :replies)
     end
   end
+  
+  test "reset counters with string argument" do
+    Topic.increment_counter('replies_count', @topic.id)
+
+    assert_difference '@topic.reload.replies_count', -1 do
+      Topic.reset_counters(@topic.id, 'replies')
+    end
+  end
+
+  test "reset counters with modularized and camelized classnames" do
+    special = SpecialTopic.create!(:title => 'Special')
+    SpecialTopic.increment_counter(:replies_count, special.id)
+
+    assert_difference 'special.reload.replies_count', -1 do
+      SpecialTopic.reset_counters(special.id, :special_replies)
+    end
+  end
 
   test "update counter with initial null value" do
     category = categories(:general)