Merge pull request #21657 from nextcloud/fix/no_undefined_in_template

Check if debugMode is defined before using it

Author: rullzer

core/templates/exception.php

@@ -14,7 +14,7 @@
 	<ul>
 		<li><?php p($l->t('Remote Address: %s', [$_['remoteAddr']])) ?></li>
 		<li><?php p($l->t('Request ID: %s', [$_['requestID']])) ?></li>
-		<?php if ($_['debugMode']): ?>
+		<?php if (isset($_['debugMode']) && $_['debugMode'] === true): ?>
 			<li><?php p($l->t('Type: %s', [$_['errorClass']])) ?></li>
 			<li><?php p($l->t('Code: %s', [$_['errorCode']])) ?></li>
 			<li><?php p($l->t('Message: %s', [$_['errorMsg']])) ?></li>