Fixed ordering when changing parent of new page

CHANGELOG.md

@@ -25,7 +25,8 @@
     * Fixed fatal error in PHP 8 when trying to access root page
     * Fixed Array->String conversion error when `languages:translations: false` [admin#1896](https://github.com/getgrav/grav-plugin-admin/issues/1896)
     * Fixed `Inflector` methods when translation is missing `GRAV.INFLECTOR_*` translations
-    * Fixed `PageObject::getRoute()` with pages which have no route
+    * Fixed exception when changing parent of new page [grav-plugin-admin#2018](https://github.com/getgrav/grav-plugin-admin/issues/2018)
+    * Fixed ordering when changing parent of new page [grav-plugin-admin#2018](https://github.com/getgrav/grav-plugin-admin/issues/2018)
 
 # v1.7.0-rc.20
 ## 12/15/2020

system/src/Grav/Common/Flex/Types/Pages/PageObject.php

@@ -320,6 +320,13 @@ public function move(PageInterface $parent)
      */
     protected function reorderSiblings(array $ordering)
     {
+        $storageKey = $this->getMasterKey();
+        $filesystem = Filesystem::getInstance(false);
+        $oldParentKey = ltrim($filesystem->dirname("/{$storageKey}"), '/');
+        $newParentKey = $this->getProperty('parent_key');
+        $isMoved = $oldParentKey !== $newParentKey;
+        $order = !$isMoved ? $this->order() : false;
+
         $parent = $this->parent();
         if (!$parent) {
             throw new RuntimeException('Cannot reorder a page which has no parent');
@@ -331,13 +338,6 @@ protected function reorderSiblings(array $ordering)
         /** @var PageCollection|null $siblings */
         $siblings = $siblings->getCollection()->withOrdered()->orderBy(['order' => 'ASC']);
 
-        $storageKey = $this->getMasterKey();
-        $filesystem = Filesystem::getInstance(false);
-        $oldParentKey = ltrim($filesystem->dirname("/{$storageKey}"), '/');
-        $newParentKey = $this->getProperty('parent_key');
-        $isMoved =  $oldParentKey !== $newParentKey;
-        $order = !$isMoved ? $this->order() : false;
-
         if ($storageKey !== null) {
             if ($order !== false) {
                 // Add current page back to the list if it's ordered.
@@ -370,7 +370,7 @@ protected function reorderSiblings(array $ordering)
         $siblings->removeElement($this);
 
         // If menu item was moved, just make it to be the last in order.
-        if ($isMoved && $order !== false) {
+        if ($isMoved && $this->order() !== false) {
             $parentKey = $this->getProperty('parent_key');
             $newParent = $this->getFlexDirectory()->getObject($parentKey, 'storage_key');
             $newSiblings = $newParent->children()->getCollection()->withOrdered();