From af60321ede0746666f36ba5cd0dfe0468440296e Mon Sep 17 00:00:00 2001
From: i-just <iwona@pixelandtonic.com>
Date: Wed, 15 Jan 2025 15:38:18 +0000
Subject: [PATCH 1/2] don't allow special relatedToXYZ arguments to make it
 into query criteria

---
 src/gql/ArgumentManager.php | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/gql/ArgumentManager.php b/src/gql/ArgumentManager.php
index 93c7ec10895..78830d77c73 100644
--- a/src/gql/ArgumentManager.php
+++ b/src/gql/ArgumentManager.php
@@ -12,6 +12,7 @@
 use craft\errors\GqlException;
 use craft\events\RegisterGqlArgumentHandlersEvent;
 use craft\gql\base\ArgumentHandlerInterface;
+use craft\gql\base\RelationArgumentHandler;
 use craft\gql\handlers\RelatedAssets;
 use craft\gql\handlers\RelatedCategories;
 use craft\gql\handlers\RelatedEntries;
@@ -154,6 +155,15 @@ public function prepareArguments(array $arguments): array
             if (!empty($arguments[$argumentName]) && $handler instanceof ArgumentHandlerInterface) {
                 $arguments = $handler->handleArgumentCollection($arguments);
             }
+            // if it's one of the relatedToXYZ arguments,
+            // if the value is empty/null unset that arg so that it doesn't go into the criteria
+            if (
+                array_key_exists($argumentName, $arguments) &&
+                empty($arguments[$argumentName]) &&
+                $handler instanceof RelationArgumentHandler
+            ) {
+                unset($arguments[$argumentName]);
+            }
         }
 
         return $arguments;

From 6e50120b52f24c747174d3dc022a4add30912601 Mon Sep 17 00:00:00 2001
From: brandonkelly <brandon@pixelandtonic.com>
Date: Wed, 15 Jan 2025 09:26:58 -0800
Subject: [PATCH 2/2] Release note

[ci skip]
---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48066f3311a..304c94f3089 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Release Notes for Craft CMS 4
 
+## Unreleased
+
+- Fixed an error that could occur when setting `relatedTo*` GraphQL arguments to `null`. ([#16433](https://github.com/craftcms/cms/issues/16433))
+
 ## 4.13.10 - 2025-01-14
 
 - Fixed a bug where the control panel could display a notice about the Craft CMS license belonging to a different domain, even when accessing the control panel from the correct domain. ([#16396](https://github.com/craftcms/cms/issues/16396))