From f9a60676627dbd6facdfbb0104b4e2fbda5c71a5 Mon Sep 17 00:00:00 2001
From: Vaidehi Joshi <vaidehi.sj@gmail.com>
Date: Wed, 28 Apr 2021 08:27:26 -0700
Subject: [PATCH] Do not create mentions when embedded within a comment liquid
 tag (#13552)

Fixes https://github.com/forem/forem/issues/13348.
---
 app/services/mentions/create_all.rb       |  8 ++++++--
 spec/services/mentions/create_all_spec.rb | 15 ++++++++++++---
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/app/services/mentions/create_all.rb b/app/services/mentions/create_all.rb
index a3a51ccfa..a7d3753d6 100644
--- a/app/services/mentions/create_all.rb
+++ b/app/services/mentions/create_all.rb
@@ -38,9 +38,13 @@ module Mentions
     def extract_usernames_from_mentions_in_text
       # The "mentioned-user" css is added by Html::Parser#user_link_if_exists
       doc = Nokogiri::HTML(notifiable.processed_html)
-      doc.css(".mentioned-user").map do |link|
-        link.text.delete("@").downcase
+
+      # Remove any mentions that are embedded within a comment liquid tag
+      non_liquid_tag_mentions = doc.css(".mentioned-user").reject do |tag|
+        tag.ancestors(".liquid-comment").any?
       end
+
+      non_liquid_tag_mentions.map { |link| link.text.delete("@").downcase }
     end
 
     def reject_notifiable_author(users)
diff --git a/spec/services/mentions/create_all_spec.rb b/spec/services/mentions/create_all_spec.rb
index a46d092c5..f6bc5395f 100644
--- a/spec/services/mentions/create_all_spec.rb
+++ b/spec/services/mentions/create_all_spec.rb
@@ -39,6 +39,15 @@ RSpec.describe Mentions::CreateAll, type: :service do
     expect(Mention.all.size).to eq(1)
   end
 
+  it "ignores mentions when embedded within a comment liquid tag" do
+    markdown = "Check out this comment: {% comment #{comment2.id_code_generated} %}"
+    comment_with_liquid_tag = create(:comment, user_id: user2.id, commentable: article, body_markdown: markdown)
+
+    comment_with_liquid_tag.save
+    described_class.call(comment_with_liquid_tag)
+    expect(Mention.all.size).to eq(0)
+  end
+
   it "creates multiple mentions for multiple users" do
     user2 = create(:user)
     comment.body_markdown = "Hello @#{user.username} @#{user2.username}, you are cool."
@@ -59,18 +68,18 @@ RSpec.describe Mentions::CreateAll, type: :service do
     expect(Mention.all.size).to eq(1)
   end
 
-  it "creates mention on creation of comment (in addition to update)" do
+  it "creates a mention on creation of comment" do
     described_class.call(comment2)
     expect(Mention.all.size).to eq(1)
   end
 
-  it "can only be created with valid mentionable" do
+  it "does not create a mention without valid mentionable" do
     comment2.update_column(:body_markdown, "")
     described_class.call(comment2)
     expect(Mention.all.size).to eq(0)
   end
 
-  it "cant mention self" do
+  it "does not create a mention when the user mentions themselves" do
     comment.body_markdown = "Me, Myself and I @#{user2.username}"
     comment.save
     described_class.call(comment)