FEATURE: keep original title when sending email notifications about a PM

app/mailers/user_notifications.rb

@@ -236,25 +236,20 @@ class UserNotifications < ActionMailer::Base
       user_name = name unless name.blank?
     end
 
-    title = notification_data[:topic_title]
     allow_reply_by_email = opts[:allow_reply_by_email] unless user.suspended?
-    use_site_subject = opts[:use_site_subject]
-    add_re_to_subject = opts[:add_re_to_subject]
-    show_category_in_subject = opts[:show_category_in_subject]
-    use_template_html = opts[:use_template_html]
     original_username = notification_data[:original_username] || notification_data[:display_username]
 
     send_notification_email(
-      title: title,
+      title: notification_data[:topic_title],
       post: post,
       username: original_username,
       from_alias: user_name,
       allow_reply_by_email: allow_reply_by_email,
-      use_site_subject: use_site_subject,
-      add_re_to_subject: add_re_to_subject,
-      show_category_in_subject: show_category_in_subject,
+      use_site_subject: opts[:use_site_subject],
+      add_re_to_subject: opts[:add_re_to_subject],
+      show_category_in_subject: opts[:show_category_in_subject],
       notification_type: notification_type,
-      use_template_html: use_template_html,
+      use_template_html: opts[:use_template_html],
       user: user
     )
   end

app/models/notification.rb

@@ -98,8 +98,8 @@ class Notification < ActiveRecord::Base
   # Be wary of calling this frequently. O(n) JSON parsing can suck.
   def data_hash
     @data_hash ||= begin
-
       return nil if data.blank?
+
       parsed = JSON.parse(data)
       return nil if parsed.blank?
 

app/services/post_alerter.rb

@@ -259,8 +259,16 @@ class PostAlerter
 
     UserActionObserver.log_notification(original_post, user, type, opts[:acting_user_id])
 
+    topic_title = post.topic.title
+    # when sending a private message email, keep the original title
+    if post.topic.private_message? && modifications = post.revisions.map(&:modifications).to_a
+      if first_title_modification = modifications.first { |m| m.has_key?("title") }
+        topic_title = first_title_modification["title"][0]
+      end
+    end
+
     notification_data = {
-      topic_title: post.topic.title,
+      topic_title: topic_title,
       original_post_id: original_post.id,
       original_post_type: original_post.post_type,
       original_username: original_username,

spec/services/post_alerter_spec.rb

@@ -150,4 +150,26 @@ describe PostAlerter do
     end
 
   end
+
+
+  describe ".create_notification" do
+
+    it "keeps the original title for PMs" do
+      user = Fabricate(:user)
+      topic = Fabricate(:private_message_topic, user: user, created_at: 1.hour.ago)
+      post = Fabricate(:post, topic: topic, created_at: 1.hour.ago)
+
+      original_title = topic.title
+
+      post.revise(user, { title: "This is the revised title" }, revised_at: Time.now)
+
+      expect {
+        PostAlerter.new.create_notification(user, Notification.types[:private_message], post)
+      }.to change { user.notifications.count }
+
+      expect(user.notifications.last.data_hash["topic_title"]).to eq(original_title)
+    end
+
+  end
+
 end