Handle the situation when GRAV_ROOT or GRAV_WEBROOT are / (#3667)

* Handle the situation when GRAV_ROOT or GARV_WEBROOT are `/`

* Update defines.php

Replaced `/` with `DS`

* Update Backups.php

Replaced `/` with `DS` in `backup` function

CHANGELOG.md

@@ -123,6 +123,7 @@
 1. [](#improved)
     * Removed outdated `xcache` setting [#3615](https://github.com/getgrav/grav/pull/3615)
     * Updated `robots.txt` [#3625](https://github.com/getgrav/grav/pull/3625)
+    * Handle the situation when GRAV_ROOT or GRAV_WEBROOT are `/` [#3625](https://github.com/getgrav/grav/pull/3667)
 1. [](#bugfix)
     * Fixed `force_ssl` redirect in case of undefined hostname [#3702](https://github.com/getgrav/grav/pull/3702)
     * Fixed an issue with duplicate identical page paths

system/defines.php

@@ -26,12 +26,12 @@
 // Absolute path to Grav root. This is where Grav is installed into.
 if (!defined('GRAV_ROOT')) {
     $path = rtrim(str_replace(DIRECTORY_SEPARATOR, DS, getenv('GRAV_ROOT') ?: getcwd()), DS);
-    define('GRAV_ROOT', $path);
+    define('GRAV_ROOT', $path ?: DS);
 }
 // Absolute path to Grav webroot. This is the path where your site is located in.
 if (!defined('GRAV_WEBROOT')) {
     $path = rtrim(getenv('GRAV_WEBROOT') ?: GRAV_ROOT, DS);
-    define('GRAV_WEBROOT', $path);
+    define('GRAV_WEBROOT', $path ?: DS);
 }
 // Relative path to user folder. This path needs to be located under GRAV_WEBROOT.
 if (!defined('GRAV_USER_PATH')) {

system/src/Grav/Common/Backup/Backups.php

@@ -218,7 +218,7 @@ public static function backup($id = 0, callable $status = null)
         if ($locator->isStream($backup_root)) {
             $backup_root = $locator->findResource($backup_root);
         } else {
-            $backup_root = rtrim(GRAV_ROOT . $backup_root, '/');
+            $backup_root = rtrim(GRAV_ROOT . $backup_root, DS) ?: DS;
         }
 
         if (!$backup_root || !file_exists($backup_root)) {