TYPO3 Core

Hey,

i had used the code Example from:
https://docs.typo3.org/typo3cms/CoreApiReference/ApiOverview/Examples/PageTrees/Index.html

At the first time, all was fine.
But After logout from the Backend, the Controller Throwed a FATAL error.

Fatal error: Call to a member function isInWebMount() on a non-object in /var/www/paramize/typo3_episch/vendor/typo3/cms/typo3/sysext/backend/Classes/Tree/View/+AbstractTreeView.php on line 756+

  while ($crazyRecursionLimiter > 0 && ($row = $this->getDataNext($res))) {
            $pageUid = ($this->table === 'pages') ? $row['uid'] : $row['pid'];
            if (!$this->getBackendUser()->isInWebMount($pageUid)) {
                // Current record is not within web mount => skip it
                continue;
            }

The Fix is maybe:

  while ($crazyRecursionLimiter > 0 && ($row = $this->getDataNext($res))) {
            $pageUid = ($this->table === 'pages') ? $row['uid'] : $row['pid'];
            // only add $GLOBALS['BE_USER'] != NULL &&
            if ($GLOBALS['BE_USER'] != NULL && !$this->getBackendUser()->isInWebMount($pageUid)) {
                // Current record is not within web mount => skip it
                continue;
            }

The Problem exist in older Versions, too:
https://forum.typo3.org/index.php/t/204838/