Merge pull request #2737 from basecamp/remember-regexp-timeout

Stop scrubbing after first regexp timeout

app/helpers/html_helper.rb

@@ -1,6 +1,7 @@
 module HtmlHelper
   def format_html(html)
-    Loofah::HTML5::DocumentFragment.parse(html).scrub!(AutoLinkScrubber.new).to_html.html_safe
+    @auto_link_scrubber ||= AutoLinkScrubber.new
+    Loofah::HTML5::DocumentFragment.parse(html).scrub!(@auto_link_scrubber).to_html.html_safe
   end
 
   def card_html_title(card)

lib/auto_link_scrubber.rb

@@ -20,12 +20,13 @@ class AutoLinkScrubber < Loofah::Scrubber
 
   def initialize
     @direction = :top_down
+    @regexp_timeout_reported = false
   end
 
   def scrub(node)
     return Loofah::Scrubber::STOP if EXCLUDED_ELEMENTS.include?(node.name)
 
-    if node.text?
+    if node.text? && !@regexp_timeout_reported
       replacement = autolink_text_node(node)
       node.replace(replacement) if replacement
     end
@@ -73,6 +74,7 @@ class AutoLinkScrubber < Loofah::Scrubber
       links
     rescue Regexp::TimeoutError => error
       Sentry.capture_exception error if Fizzy.saas?
+      @regexp_timeout_reported = true
       []
     end