From 2d08e306ae7dd3951ca44cd55f636b4cff6dfcff Mon Sep 17 00:00:00 2001
From: Sai Asish Y <say.apm35@gmail.com>
Date: Wed, 26 Aug 2026 01:58:27 -0700
Subject: [PATCH] fix: prevent crash when relation query constraint contains
 null

Signed-off-by: Sai Asish Y <say.apm35@gmail.com>
---
 spec/RestQuery.spec.js                | 27 +++++++++++++++++++++++++++
 src/Controllers/DatabaseController.js |  6 +++---
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/spec/RestQuery.spec.js b/spec/RestQuery.spec.js
index 3438febf76..837ab5c6fe 100644
--- a/spec/RestQuery.spec.js
+++ b/spec/RestQuery.spec.js
@@ -589,6 +589,33 @@ describe('RestQuery.each', () => {
     expect(resultsTwo.length).toBe(1);
   });
 
+  it('should not throw when a relation query constraint contains null', async () => {
+    const objectA = new Parse.Object('Letter', { value: 'A' });
+    const object1 = new Parse.Object('Number', { value: '1' });
+    await object1.save();
+    objectA.relation('numbers').add(object1);
+    await objectA.save();
+
+    const config = Config.get('test');
+
+    for (const [restWhere, expectedCount] of [
+      [{ numbers: { $in: [null] } }, 0],
+      [{ numbers: { $nin: [null] } }, 1],
+      [{ numbers: { $ne: null, $in: [] } }, 0],
+    ]) {
+      const query = await RestQuery({
+        method: RestQuery.Method.find,
+        config,
+        auth: auth.master(config),
+        className: 'Letter',
+        restWhere,
+      });
+      const results = [];
+      await query.each(result => results.push(result));
+      expect(results.length).toBe(expectedCount);
+    }
+  });
+
   it('test afterSave response object is return', done => {
     Parse.Cloud.beforeSave('TestObject2', function (req) {
       req.object.set('tobeaddbefore', true);
diff --git a/src/Controllers/DatabaseController.js b/src/Controllers/DatabaseController.js
index d598cacac5..8ca19a88b5 100644
--- a/src/Controllers/DatabaseController.js
+++ b/src/Controllers/DatabaseController.js
@@ -1095,13 +1095,13 @@ class DatabaseController {
           if (constraintKey === 'objectId') {
             relatedIds = [query[key].objectId];
           } else if (constraintKey == '$in') {
-            relatedIds = query[key]['$in'].map(r => r.objectId);
+            relatedIds = query[key]['$in'].map(r => r?.objectId);
           } else if (constraintKey == '$nin') {
             isNegation = true;
-            relatedIds = query[key]['$nin'].map(r => r.objectId);
+            relatedIds = query[key]['$nin'].map(r => r?.objectId);
           } else if (constraintKey == '$ne') {
             isNegation = true;
-            relatedIds = [query[key]['$ne'].objectId];
+            relatedIds = [query[key]['$ne']?.objectId];
           } else {
             return;
           }