diff --git a/lib/setuplib.php b/lib/setuplib.php
index 470a15a924e..eb2d347bbe0 100644
--- a/lib/setuplib.php
+++ b/lib/setuplib.php
@@ -71,7 +71,7 @@ function get_whoops(): ?\Whoops\Run {
         return null;
     }
 
-    if (!$CFG->debugdisplay) {
+    if (empty($CFG->debugdisplay)) {
         return null;
     }