From 1302fe9da299a8906d598e1f15977411dc0b0ec8 Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike@37signals.com>
Date: Mon, 2 Jun 2025 14:10:04 -0400
Subject: [PATCH] Autolinking shouldn't include final punctuation.

---
 app/helpers/html_helper.rb       | 11 ++++++++++-
 test/helpers/html_helper_test.rb | 24 ++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/app/helpers/html_helper.rb b/app/helpers/html_helper.rb
index f61da26c1..82a18722d 100644
--- a/app/helpers/html_helper.rb
+++ b/app/helpers/html_helper.rb
@@ -34,7 +34,16 @@ module HtmlHelper
 
     def auto_link_urls(linked_content)
       linked_content.gsub!(URL_REGEXP) do |match|
-        %(<a href="#{match}" rel="noreferrer">#{match}</a>)
+        url, trailing_punct = extract_url_and_punctuation(match)
+        %(<a href="#{url}" rel="noreferrer">#{url}</a>#{trailing_punct})
+      end
+    end
+
+    def extract_url_and_punctuation(url_match)
+      if url_match.end_with?(".", "?", ",", ":")
+        [ url_match[..-2], url_match[-1] ]
+      else
+        [ url_match, "" ]
       end
     end
 
diff --git a/test/helpers/html_helper_test.rb b/test/helpers/html_helper_test.rb
index 818ffa57b..b2536b5c4 100644
--- a/test/helpers/html_helper_test.rb
+++ b/test/helpers/html_helper_test.rb
@@ -5,6 +5,30 @@ class HtmlHelperTest < ActionView::TestCase
     assert_equal_html \
       %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a></p>),
       format_html("<p>Check this: https://example.com</p>")
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com/" rel="noreferrer">https://example.com/</a></p>),
+      format_html("<p>Check this: https://example.com/</p>")
+  end
+
+  test "does not include punctuation in URL autolinking" do
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a>!</p>),
+      format_html("<p>Check this: https://example.com!</p>")
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a>.</p>),
+      format_html("<p>Check this: https://example.com.</p>")
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a>?</p>),
+      format_html("<p>Check this: https://example.com?</p>")
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a>,</p>),
+      format_html("<p>Check this: https://example.com,</p>")
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a>:</p>),
+      format_html("<p>Check this: https://example.com:</p>")
+    assert_equal_html \
+      %(<p>Check this: <a href="https://example.com" rel="noreferrer">https://example.com</a>;</p>),
+      format_html("<p>Check this: https://example.com;</p>")
   end
 
   test "respect existing links" do