TYPO3 Core

This function should return the first domain found in rootline.
Now "getRecordsByField" can return an empty array, so we have to check that the result is a non-empty array.

TYPO3\CMS\Backend\Utility\BackendUtility:firstDomainRecord (line 3997)

if (is_array($dRec) && $dRec) {
    $dRecord = reset($dRec);
    return rtrim($dRecord['domainName'], '/');
}