FIX: posting my fail because there are no tags

lib/discourse_tagging.rb

@@ -27,7 +27,7 @@ module DiscourseTagging
 
     return [] unless guardian.can_tag_topics?
 
-    return unless tags
+    return unless tags.present?
 
     tags.map! {|t| clean_tag(t) }
     tags.delete_if {|t| t.blank? }

lib/post_creator.rb

@@ -438,11 +438,13 @@ class PostCreator
   end
 
   def auto_notify_for_tags
-    tags = DiscourseTagging.tags_for_saving(@opts[:tags], @guardian)
-    if tags.present?
-      @topic.custom_fields.update(DiscourseTagging::TAGS_FIELD_NAME => tags)
-      @topic.save
-      DiscourseTagging.auto_notify_for(tags, @topic)
+    if SiteSetting.tagging_enabled
+      tags = DiscourseTagging.tags_for_saving(@opts[:tags], @guardian)
+      if tags.present?
+        @topic.custom_fields.update(DiscourseTagging::TAGS_FIELD_NAME => tags)
+        @topic.save
+        DiscourseTagging.auto_notify_for(tags, @topic)
+      end
     end
   end