FIX: include topic excerpt in topic/message invite mail for existing user

app/mailers/user_notifications.rb

@@ -79,10 +79,6 @@ class UserNotifications < ActionMailer::Base
     end
   end
 
-  def user_invited_to_private_message(user, opts)
-    notification_email(user, opts)
-  end
-
   def user_replied(user, opts)
     opts[:allow_reply_by_email] = true
     opts[:use_site_subject] = true
@@ -124,7 +120,13 @@ class UserNotifications < ActionMailer::Base
     notification_email(user, opts)
   end
 
+  def user_invited_to_private_message(user, opts)
+    opts[:use_template_html] = true
+    notification_email(user, opts)
+  end
+
   def user_invited_to_topic(user, opts)
+    opts[:use_template_html] = true
     opts[:show_category_in_subject] = true
     notification_email(user, opts)
   end
@@ -193,6 +195,7 @@ class UserNotifications < ActionMailer::Base
     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_hash[:original_username] || @notification.data_hash[:display_username]
 
     send_notification_email(
@@ -205,6 +208,7 @@ class UserNotifications < ActionMailer::Base
       add_re_to_subject: add_re_to_subject,
       show_category_in_subject: show_category_in_subject,
       notification_type: notification_type,
+      use_template_html: use_template_html,
       user: user
     )
 
@@ -248,20 +252,26 @@ class UserNotifications < ActionMailer::Base
       end
     end
 
-    html = UserNotificationRenderer.new(Rails.configuration.paths["app/views"]).render(
-      template: 'email/notification',
-      format: :html,
-      locals: { context_posts: context_posts,
-                post: post,
-                classes: RTL.new(user).css_class
-      }
-    )
+    topic_excerpt = ""
+    if opts[:use_template_html]
+      topic_excerpt = post.excerpt.gsub("\n", " ") if post.is_first_post? && post.excerpt
+    else
+      html = UserNotificationRenderer.new(Rails.configuration.paths["app/views"]).render(
+        template: 'email/notification',
+        format: :html,
+        locals: { context_posts: context_posts,
+                  post: post,
+                  classes: RTL.new(user).css_class
+        }
+      )
+    end
 
     template = "user_notifications.user_#{notification_type}"
     template << "_pm" if post.topic.private_message?
 
     email_opts = {
       topic_title: title,
+      topic_excerpt: topic_excerpt,
       message: email_post_markdown(post),
       url: post.url,
       post_id: post.id,
@@ -277,6 +287,8 @@ class UserNotifications < ActionMailer::Base
       include_respond_instructions: !user.suspended?,
       template: template,
       html_override: html,
+      site_description: SiteSetting.site_description,
+      site_title: SiteSetting.title,
       style: :notification
     }
 

config/locales/server.en.yml

@@ -1771,16 +1771,34 @@ en:
     user_invited_to_private_message_pm:
       subject_template: "[%{site_name}] %{username} invited you to a message '%{topic_title}'"
       text_body_template: |
-        %{username} invited you to a message '%{topic_title}' on %{site_name}:
 
-        Please visit this link to view the topic: %{base_url}%{url}
+        %{username} invited you to a message
+
+        > **%{topic_title}**
+        >
+        > %{topic_excerpt}
+
+        at
+
+        > %{site_title} -- %{site_description}
+
+        Please visit this link to view the message: %{base_url}%{url}
 
     user_invited_to_topic:
       subject_template: "[%{site_name}] %{username} invited you to a topic '%{topic_title}'"
       text_body_template: |
-        %{username} invited you to a topic '%{topic_title}' on %{site_name}:
 
-        Please visit this link to view the topic: %{base_url}%{url}
+        %{username} invited you to a discussion
+
+        > **%{topic_title}**
+        >
+        > %{topic_excerpt}
+
+        at
+
+        > %{site_title} -- %{site_description}
+
+        Please visit this link to view the message: %{base_url}%{url}
 
     user_replied:
       subject_template: "[%{site_name}] %{topic_title}"