From 5e9eb9fc83912e39c668b0a676dddf0f09640132 Mon Sep 17 00:00:00 2001
From: Dan Wallis <mrdanwallis@gmail.com>
Date: Wed, 3 Feb 2021 00:01:24 +0000
Subject: [PATCH] Avoid infinite loop when Parse Error occurs

---
 Magento2/Sniffs/Security/XssTemplateSniff.php   | 6 ++++--
 Magento2/Tests/Security/XssTemplateUnitTest.inc | 3 +++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/Magento2/Sniffs/Security/XssTemplateSniff.php b/Magento2/Sniffs/Security/XssTemplateSniff.php
index aa2accbe..43bdfecc 100644
--- a/Magento2/Sniffs/Security/XssTemplateSniff.php
+++ b/Magento2/Sniffs/Security/XssTemplateSniff.php
@@ -249,8 +249,10 @@ private function parseLineStatement($start, $end)
         $posOfLastInlineThen = $this->findLastInScope(T_INLINE_THEN, $start, $end);
         if ($posOfLastInlineThen !== false) {
             $posOfInlineElse = $this->file->findNext(T_INLINE_ELSE, $posOfLastInlineThen, $end);
-            $this->addStatement($posOfLastInlineThen + 1, $posOfInlineElse);
-            $this->addStatement($posOfInlineElse + 1, $end);
+            if ($posOfInlineElse !== false) {
+                $this->addStatement($posOfLastInlineThen + 1, $posOfInlineElse);
+                $this->addStatement($posOfInlineElse + 1, $end);
+            }
             $parsed = true;
         } else {
             do {
diff --git a/Magento2/Tests/Security/XssTemplateUnitTest.inc b/Magento2/Tests/Security/XssTemplateUnitTest.inc
index eefb2c70..6a9f225d 100644
--- a/Magento2/Tests/Security/XssTemplateUnitTest.inc
+++ b/Magento2/Tests/Security/XssTemplateUnitTest.inc
@@ -57,3 +57,6 @@ echo $var;
 <?php echo $block->escapeCss($css); ?>
 <?php echo $block->getJsLayout($jsLayout); ?>
 <?= /* @noEscape */ json_encode($config) ?>
+
+<!-- intentional parse error -->
+<?= $block->escapeUrl($block->getUrl('no-route')) <?= $block->getBaseUrl() ?>