From 9513e7be6dc3260a9e1b13be27746424d7565c96 Mon Sep 17 00:00:00 2001
From: Martin Brennan <martin@discourse.org>
Date: Thu, 1 Dec 2022 19:48:24 +1000
Subject: [PATCH] FIX: Email hashtag-cooked text replacement error (#19278)

In some cases (e.g. user notification emails) we
are passing an excerpted/stripped version of the
post HTML to Email::Styles, at which point the
<span> elements surrounding the hashtag text have
been stripped. This caused an error when trying to
remove that element to replace the text.

Instead we can just remove all elements inside
a.hashtag-cooked and replace with the raw #hashtag
text which will work in more cases.
---
 lib/email/styles.rb           | 5 ++---
 spec/lib/email/styles_spec.rb | 9 +++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/lib/email/styles.rb b/lib/email/styles.rb
index ba2b56fcaf6..cd561eb8b58 100644
--- a/lib/email/styles.rb
+++ b/lib/email/styles.rb
@@ -326,11 +326,10 @@ module Email
 
     def decorate_hashtags
       @fragment.search(".hashtag-cooked").each do |hashtag|
-        hashtag_text = hashtag.search("span").first
-        hashtag_text.add_next_sibling(<<~HTML)
+        hashtag.children.each(&:remove)
+        hashtag.add_child(<<~HTML)
           <span>##{hashtag["data-slug"]}</span>
         HTML
-        hashtag_text.remove
       end
     end
 
diff --git a/spec/lib/email/styles_spec.rb b/spec/lib/email/styles_spec.rb
index 4a6f18bf0ef..62d31c4b479 100644
--- a/spec/lib/email/styles_spec.rb
+++ b/spec/lib/email/styles_spec.rb
@@ -104,6 +104,15 @@ RSpec.describe Email::Styles do
       expect(frag.at('a')).to be_present
       expect(frag.at('a')['href']).to eq(original_url)
     end
+
+    it "replaces hashtag-cooked text with raw #hashtag" do
+      hashtag_html = "<a class=\"hashtag-cooked\" href=\"#{Discourse.base_url}/c/123/dev\" data-type=\"category\" data-slug=\"dev\"><svg class=\"fa d-icon d-icon-folder svg-icon svg-node\"><use href=\"#folder\"></use></svg><span>Dev Zone</span></a>"
+      frag = html_fragment(hashtag_html)
+      expect(frag.at("a").text.chomp).to eq("#dev")
+      hashtag_html = "<a class=\"hashtag-cooked\" href=\"#{Discourse.base_url}/c/123/dev\" data-type=\"category\" data-slug=\"dev\"><svg class=\"fa d-icon d-icon-folder svg-icon svg-node\">Dev Zone</a>"
+      frag = html_fragment(hashtag_html)
+      expect(frag.at("a").text.chomp).to eq("#dev")
+    end
   end
 
   describe "rewriting protocol relative URLs to the forum" do