Merge pull request joomla#1448 from pjwiseman/28912

[#28912] Browser doesn't respond when debug language is enabled

libraries/joomla/language/language.php

@@ -824,7 +824,7 @@ protected function parse($filename)
 
 			// Initialise variables for manually parsing the file for common errors.
 			$blacklist = array('YES', 'NO', 'NULL', 'FALSE', 'ON', 'OFF', 'NONE', 'TRUE');
-			$regex = '/^(|(\[[^\]]*\])|([A-Z][A-Z0-9_\-\.]*\s*=(\s*(("([^"]|\\\")*")|(_QQ_)))+))\s*(;.*)?$/';
+			$regex = '/^(|(\[[^\]]*\])|([A-Z][A-Z0-9_\-\.]*\s*=(\s*(("[^"]*")|(_QQ_)))+))\s*(;.*)?$/';
 			$this->debug = false;
 			$errors = array();
 
@@ -842,6 +842,9 @@ protected function parse($filename)
 				// Check that the key is not in the blacklist and that the line format passes the regex.
 				$key = strtoupper(trim(substr($line, 0, strpos($line, '='))));
 
+				// Workaround to reduce regex complexity when matching escaped quotes
+				$line = str_replace('\"', '_QQ_', $line);
+
 				if (!preg_match($regex, $line) || in_array($key, $blacklist))
 				{
 					$errors[] = $lineNumber;