Set maintenance mode to update when running updates (#3606)

Author: Berdir

src/Commands/core/UpdateDBCommands.php

@@ -164,6 +164,11 @@ public function updateDoOne($module, $number, $dependency_map, &$context)
     {
         $function = $module . '_update_' . $number;
 
+        // Disable config entity overrides.
+        if (!defined('MAINTENANCE_MODE')) {
+            define('MAINTENANCE_MODE', 'update');
+        }
+
         // If this update was aborted in a previous step, or has a dependency that
         // was aborted in a previous step, go no further.
         if (!empty($context['results']['#abort']) && array_intersect($context['results']['#abort'], array_merge($dependency_map, [$function]))) {
@@ -246,6 +251,11 @@ public function updateDoOnePostUpdate($function, &$context)
     {
         $ret = [];
 
+        // Disable config entity overrides.
+        if (!defined('MAINTENANCE_MODE')) {
+            define('MAINTENANCE_MODE', 'update');
+        }
+
         // If this update was aborted in a previous step, or has a dependency that was
         // aborted in a previous step, go no further.
         if (!empty($context['results']['#abort'])) {