From eb98597220c835bce0689f44e68105769965b12e Mon Sep 17 00:00:00 2001
From: Matias Griese <matias@trilbymedia.com>
Date: Wed, 20 Jan 2021 12:24:40 +0200
Subject: [PATCH] Flex Pages: Fixed fatal error when trying to move a page to
 Root (/) [#3161]

---
 CHANGELOG.md                                           | 1 +
 system/src/Grav/Common/Flex/Types/Pages/PageObject.php | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 62adc455c..5cd63de01 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
     * Sanitize valid Page extensions from `Page::template_format()`
     * Fixed `bin/gpm index` erroring out [#3158](https://github.com/getgrav/grav/issues/3158)
     * Fixed `bin/gpm selfupgrade` failing to report failed Grav update [#3116](https://github.com/getgrav/grav/issues/3116)
+    * Flex Pages: Fixed fatal error when trying to move a page to Root (/) [#3161](https://github.com/getgrav/grav/issues/3161)
 
 # v1.7.0
 ## 01/19/2021
diff --git a/system/src/Grav/Common/Flex/Types/Pages/PageObject.php b/system/src/Grav/Common/Flex/Types/Pages/PageObject.php
index 98b949ebe..1d4f9b981 100644
--- a/system/src/Grav/Common/Flex/Types/Pages/PageObject.php
+++ b/system/src/Grav/Common/Flex/Types/Pages/PageObject.php
@@ -372,7 +372,14 @@ class PageObject extends FlexPageObject
         // If menu item was moved, just make it to be the last in order.
         if ($isMoved && $this->order() !== false) {
             $parentKey = $this->getProperty('parent_key');
-            $newParent = $this->getFlexDirectory()->getObject($parentKey, 'storage_key');
+            if ($parentKey === '') {
+                $newParent = $this->getFlexDirectory()->getIndex()->getRoot();
+            } else {
+                $newParent = $this->getFlexDirectory()->getObject($parentKey, 'storage_key');
+                if (!$newParent instanceof PageInterface) {
+                    throw new RuntimeException("New parent page '{$parentKey}' not found.");
+                }
+            }
             $newSiblings = $newParent->children()->getCollection()->withOrdered();
             $order = 0;
             foreach ($newSiblings as $sibling) {