1 files changed, 17 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index 175019a72b..007e3bc555 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -63,7 +63,15 @@ module ActiveRecord
         end
 
         save_through_record(record)
-        update_counter(1)
+        if has_cached_counter? && !through_reflection_updates_counter_cache?
+          ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc)
+            Automatic updating of counter caches on through associations has been
+            deprecated, and will be removed in Rails 5.0. Instead, please set the
+            appropriate counter_cache options on the has_many and belongs_to for
+            your associations to #{through_reflection.name}.
+          MESSAGE
+          update_counter_in_database(1)
+        end
         record
       end
 
@@ -93,7 +101,9 @@ module ActiveRecord
         end
 
         def through_scope_attributes
-          scope.where_values_hash(through_association.reflection.name.to_s).except!(through_association.reflection.foreign_key)
+          scope.where_values_hash(through_association.reflection.name.to_s).
+            except!(through_association.reflection.foreign_key,
+                    through_association.reflection.klass.inheritance_column)
         end
 
         def save_through_record(record)
@@ -216,6 +226,11 @@ module ActiveRecord
         def invertible_for?(record)
           false
         end
+
+        def through_reflection_updates_counter_cache?
+          counter_name = cached_counter_attribute_name
+          inverse_updates_counter_named?(counter_name, through_reflection)
+        end
     end
   end
 end