Ticket #28013: wp.maintenance.patch

wp-admin/includes/class-wp-upgrader.php

@@ -816 +816 @@
                         $this->skin->feedback('maintenance_start');
                         // Create maintenance file to signal that we are upgrading
                         $maintenance_string = '<?php $upgrading = ' . time() . '; ?>';
-                        $wp_filesystem->delete($file);
+                        $wp_filesystem->delete($file, false, 'f');
                         $wp_filesystem->put_contents($file, $maintenance_string, FS_CHMOD_FILE);
-                } elseif ( ! $enable && $wp_filesystem->exists( $file ) ) {
+                } else {
                         $this->skin->feedback('maintenance_end');
-                        $wp_filesystem->delete($file);
+                        $wp_filesystem->delete($file, false, 'f');
                 }
         }