FIX: Fancify titles when using experimental topic translation (#224)

In the existing method of translation, we show the translated titles below the post cooked.

When using the same already-translated titles for the experimental feature, it would result in the H1 rendering into large text in the topic title.

We've been sending the `topic.title` in for translation, instead of the escaped `topic.fancy_title`, which works well for the existing method. I had considered changing our implementation to [send the fancy_titles (escaped) in for translation instead](#222), but that would result in our existing methods titles being double-escaped.

To keep compatibility between existing and experimental, I will only escape it for the experimental feature. This commit does that.

Author: nattsw

plugin.rb

@@ -73,20 +73,25 @@ module ::DiscourseTranslator
   register_modifier(:topic_serializer_fancy_title) do |fancy_title, serializer|
     if !SiteSetting.experimental_topic_translation ||
          serializer.scope.request.params["show"] == "original" ||
-         serializer.object.detected_locale == I18n.locale.to_s.gsub("_", "-")
+         serializer.object.locale_matches?(I18n.locale)
       fancy_title
     else
-      serializer.object.translation_for(I18n.locale).presence
+      serializer.object.translation_for(I18n.locale).presence&.then { |t| Topic.fancy_title(t) }
     end
   end
 
   register_modifier(:topic_view_serializer_fancy_title) do |fancy_title, serializer|
     if !SiteSetting.experimental_topic_translation ||
          serializer.scope.request.params["show"] == "original" ||
-         serializer.object.topic.detected_locale == I18n.locale.to_s.gsub("_", "-")
+         serializer.object.topic.locale_matches?(I18n.locale)
       fancy_title
     else
-      serializer.object.topic.translation_for(I18n.locale).presence
+      serializer
+        .object
+        .topic
+        .translation_for(I18n.locale)
+        .presence
+        &.then { |t| Topic.fancy_title(t) }
     end
   end
 end

spec/serializers/basic_topic_serializer_spec.rb

@@ -13,8 +13,8 @@
 
   describe "#fancy_title" do
     let!(:guardian) { Guardian.new(user) }
-    let!(:original_title) { "FUS ROH DAAHHH" }
-    let!(:jap_title) { "フス・ロ・ダ・ア" }
+    let!(:original_title) { "<h1>FUS ROH DAAHHH</h1>" }
+    let!(:jap_title) { "<h1>フス・ロ・ダ・ア</h1>" }
 
     before do
       topic.title = original_title
@@ -55,7 +55,7 @@ def serialize_topic(guardian_user: user, params: {})
 
     it "returns translated title in fancy_title when translation exists for current locale" do
       topic.set_translation("ja", jap_title)
-      expect(serialize_topic.fancy_title).to eq(jap_title)
+      expect(serialize_topic.fancy_title).to eq("&lt;h1&gt;フス・ロ・ダ・ア&lt;/h1&gt;")
     end
   end
 end

spec/serializers/topic_view_serializer_spec.rb

@@ -36,8 +36,8 @@
     fab!(:topic)
 
     let!(:guardian) { Guardian.new(user) }
-    let!(:original_title) { "FUS ROH DAAHHH" }
-    let!(:jap_title) { "フス・ロ・ダ・ア" }
+    let!(:original_title) { "<h1>FUS ROH DAAHHH</h1>" }
+    let!(:jap_title) { "<h1>フス・ロ・ダ・ア</h1>" }
 
     before do
       topic.title = original_title
@@ -78,7 +78,7 @@ def serialize_topic(guardian_user: user, params: {})
 
     it "returns translated title in fancy_title when translation exists for current locale" do
       topic.set_translation("ja", jap_title)
-      expect(serialize_topic.fancy_title).to eq(jap_title)
+      expect(serialize_topic.fancy_title).to eq("&lt;h1&gt;フス・ロ・ダ・ア&lt;/h1&gt;")
     end
   end
 end