MC-30109: Deleting an empty user model caused deleting admin role

Author: zakdma

app/code/Magento/User/Model/ResourceModel/User.php

@@ -259,11 +259,13 @@ public function delete(\Magento\Framework\Model\AbstractModel $user)
         $uid = $user->getId();
         $connection->beginTransaction();
         try {
-            $connection->delete($this->getMainTable(), ['user_id = ?' => $uid]);
-            $connection->delete(
-                $this->getTable('authorization_role'),
-                ['user_id = ?' => $uid, 'user_type = ?' => UserContextInterface::USER_TYPE_ADMIN]
-            );
+            if ($uid) {
+                $connection->delete($this->getMainTable(), ['user_id = ?' => $uid]);
+                $connection->delete(
+                    $this->getTable('authorization_role'),
+                    ['user_id = ?' => $uid, 'user_type = ?' => UserContextInterface::USER_TYPE_ADMIN]
+                );
+            }
         } catch (\Magento\Framework\Exception\LocalizedException $e) {
             $connection->rollBack();
             return false;