From 215801ef954c3d9e0c60814f1131711a3d1a7d2a Mon Sep 17 00:00:00 2001
From: Mantas Masalskis <mm@zammad.com>
Date: Thu, 11 Feb 2021 08:51:52 +0100
Subject: [PATCH] Fixes #3393 - HTML structure that is not parseable by jQuery
 causes JavaScript error that breaks Ticket Zoom view.

---
 .../javascripts/app/lib/app_post/utils.coffee | 14 +++++++++--
 public/assets/tests/html_utils.js             | 25 +++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/app/assets/javascripts/app/lib/app_post/utils.coffee b/app/assets/javascripts/app/lib/app_post/utils.coffee
index 7430b26be..dad482357 100644
--- a/app/assets/javascripts/app/lib/app_post/utils.coffee
+++ b/app/assets/javascripts/app/lib/app_post/utils.coffee
@@ -771,7 +771,7 @@ class App.Utils
     if @isMicrosoftOffice message
       return @signatureIdentifyByPlaintext message
 
-    message_element = $($.parseHTML(message))
+    message_element = $(App.Utils.safeParseHtml(message))
     if message_element.length == 1 && $(message_element[0])?.children()?.length
       message_element[0].innerHTML = @signatureIdentifyByHtmlHelper(message_element[0].innerHTML)
       return message_element[0].outerHTML
@@ -792,7 +792,10 @@ class App.Utils
       return true if tag is 'DIV' && (el.data('signature') || el.prop('class') is 'yahoo_quoted')
       _.some el.children(), (el) -> isQuoteOrSignature el
 
-    $('<div/>').html(message).contents().each (index, node) ->
+    try content = $('<div/>').html(message)
+    catch e then content = $('<div/>').html('<div>' + message + '</div>')
+
+    content.contents().each (index, node) ->
       text = $(node).text()
       if node.nodeType == Node.TEXT_NODE
         # convert text back to HTML as it was before
@@ -1457,3 +1460,10 @@ class App.Utils
         htmlString = App.Utils.text2html(text)
 
     htmlString
+
+  # Parses HTML text to DOM tree
+  # jQuery's parseHTML sometimes fail when element does not have a single root element
+  # in that case, fall back to fake root element and try again
+  @safeParseHtml: (input) ->
+    try $.parseHTML(input)
+    catch e then $.parseHTML('<div>' + input + '</div>')[0].childNodes
diff --git a/public/assets/tests/html_utils.js b/public/assets/tests/html_utils.js
index f75dfd75f..4d7663670 100644
--- a/public/assets/tests/html_utils.js
+++ b/public/assets/tests/html_utils.js
@@ -1051,6 +1051,14 @@ test("identify signature by HTML", function() {
   var result  = App.Utils.signatureIdentifyByHtml(message)
   equal(result, should)
 
+
+  // test if, according to jQuery, invalid HTML does not cause a a crash
+  // https://github.com/zammad/zammad/issues/3393
+  message = "<td></td><table></table><div>test 123 </div>"
+  should  = message
+  result  = App.Utils.signatureIdentifyByHtml(message)
+  equal(result, should)
+
   // simple case 1
   message = '<div>actual content</div><blockquote>quoted content</blockquote>'
   should  = '<div>actual content</div><span class="js-signatureMarker"></span><blockquote>quoted content</blockquote>'
@@ -3386,3 +3394,20 @@ test('App.Utils.signatureIdentifyByHtmlHelper()', function() {
 
   equal(result, "&lt;script&gt;alert('fish2');&lt;/script&gt;<span class=\"js-signatureMarker\"></span><blockquote></blockquote>", 'signatureIdentifyByHtmlHelper does not reactivate alert')
 });
+
+test("#safeParseHtml", function() {
+  var unwrap = input => $('<div>').html(input)[0].innerHTML
+
+  var html = "<div>test 123 </div>"
+  var result  = App.Utils.safeParseHtml(html)
+  var should = html
+  equal(unwrap(result), html)
+
+
+  // test if, according to jQuery, invalid HTML does not cause a a crash
+  // https://github.com/zammad/zammad/issues/3393
+  html   = "<td></td><table></table><div>test 123 </div>"
+  should = "<table></table><div>test 123 </div>"
+  result = App.Utils.safeParseHtml(html)
+  equal(unwrap(result), should)
+})