FIX: no_ads_for_tags support for hidden tags

Hidden tags aren't sent to the client, so they couldn't be used to
disable ads on topic pages. Do this calculation on the server.
Topic list pages for tags can continue to check on the client because
non-staff get a 404 error when trying to view a hidden tag's topic list.

assets/javascripts/discourse/components/ad-component.js.es6

@@ -13,18 +13,18 @@ export default Ember.Component.extend({
     "router.currentRoute.parent.attributes.category.slug"
   ),
 
+  // Server needs to compute this in case hidden tags are being used.
+  topicTagsDisableAds: Ember.computed.alias(
+    "router.currentRoute.parent.attributes.tags_disable_ads"
+  ),
+
   @computed(
-    "router.currentRoute.parent.attributes.tags",
     "router.currentRoute.attributes.__type",
     "router.currentRoute.attributes.id"
   )
-  currentTags(tagsArray, type, tag) {
-    if (tagsArray) {
-      return tagsArray;
-    }
-
+  topicListTag(type, tag) {
     if (type === "tag" && tag) {
-      return [tag];
+      return tag;
     }
   },
 
@@ -49,21 +49,19 @@ export default Ember.Component.extend({
     return !groupNames.any(g => noAdsGroupNames.includes(g));
   },
 
-  @computed("currentCategoryId", "currentTags")
-  showOnCurrentPage(categoryId, currentTags) {
+  @computed("currentCategoryId", "topicTagsDisableAds", "topicListTag")
+  showOnCurrentPage(categoryId, topicTagsDisableAds, topicListTag) {
     return (
+      !topicTagsDisableAds &&
       (!categoryId ||
         !this.siteSettings.no_ads_for_categories ||
         !this.siteSettings.no_ads_for_categories
           .split("|")
           .includes(categoryId.toString())) &&
-      (!currentTags ||
+      (!topicListTag ||
         !this.siteSettings.no_ads_for_tags ||
-        Ember.isEmpty(
-          this.siteSettings.no_ads_for_tags
-            .split("|")
-            .filter(tag => currentTags.includes(tag))
-        ))
+        !this.siteSettings.no_ads_for_tags.split("|").includes(topicListTag)
+      )
     );
   },
 

plugin.rb

@@ -39,6 +39,12 @@ after_initialize do
     AdPlugin::HouseAdSetting.settings_and_ads
   end
 
+  add_to_serializer :topic_view, :tags_disable_ads do
+    return false if !SiteSetting.tagging_enabled || !SiteSetting.no_ads_for_tags.present?
+    return false if object.topic.tags.empty?
+    !(SiteSetting.no_ads_for_tags.split('|') & object.topic.tags.map(&:name)).empty?
+  end
+
   class ::AdstxtController < ::ApplicationController
     skip_before_action :check_xhr