Fix bug where some unix timestamps were not handled correctly by rcube_utils::anytodatetime() (#6212)

CHANGELOG

@@ -9,6 +9,7 @@ CHANGELOG Roundcube Webmail
 - Fix security issue in remote content blocking on HTML image and style tags (#6178)
 - Added 9pt and 11pt to the list of font sizes in HTML editor
 - Fix handling encoding of HTML tags in "inline" JSON output (#6207)
+- Fix bug where some unix timestamps were not handled correctly by rcube_utils::anytodatetime() (#6212)
 
 RELEASE 1.3.4
 -------------

program/lib/Roundcube/rcube_utils.php

@@ -752,7 +752,8 @@ class rcube_utils
         // try to parse string with DateTime first
         if (!empty($date)) {
             try {
-                $dt = $timezone ? new DateTime($date, $timezone) : new DateTime($date);
+                $_date = preg_match('/^[0-9]+$/', $date) ? "@$date" : $date;
+                $dt    = $timezone ? new DateTime($_date, $timezone) : new DateTime($_date);
             }
             catch (Exception $e) {
                 // ignore

tests/Framework/Utils.php

@@ -385,6 +385,7 @@ class Framework_Utils extends PHPUnit_Framework_TestCase
             'Jan 1st 2014 +0800' => '2013-12-31 18:00',  // result in target timezone
             'Jan 1st 14 45:42'   => '2014-01-01 00:00',  // force fallback to rcube_utils::strtotime()
             'Jan 1st 2014 UK'    => '2014-01-01 00:00',
+            '1520587800'         => '2018-03-09 11:30',  // unix timestamp conversion
             'Invalid date'       => false,
         );