From 846fe18731da035a0a3a9a4345fb27bfc8c05ec2 Mon Sep 17 00:00:00 2001
From: Janic Duplessis <janicduplessis@gmail.com>
Date: Tue, 31 Oct 2023 16:44:56 -0400
Subject: [PATCH 1/2] Don't remove nulls in cache merge

---
 lib/OnyxCache.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/OnyxCache.js b/lib/OnyxCache.js
index f65da089..bdae5c0a 100644
--- a/lib/OnyxCache.js
+++ b/lib/OnyxCache.js
@@ -121,7 +121,7 @@ class OnyxCache {
 
         // lodash adds a small overhead so we don't use it here
         // eslint-disable-next-line prefer-object-spread, rulesdir/prefer-underscore-method
-        this.storageMap = Object.assign({}, utils.fastMerge(this.storageMap, data));
+        this.storageMap = Object.assign({}, utils.fastMerge(this.storageMap, data, false));
 
         const storageKeys = this.getAllKeys();
         const mergedKeys = _.keys(data);

From c5828fbccda270ee2e3b4c2b3624e4bb6f664fa6 Mon Sep 17 00:00:00 2001
From: Janic Duplessis <janicduplessis@gmail.com>
Date: Tue, 31 Oct 2023 16:59:43 -0400
Subject: [PATCH 2/2] Add test

---
 tests/unit/onyxCacheTest.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tests/unit/onyxCacheTest.js b/tests/unit/onyxCacheTest.js
index 65fa7ea3..fa03e362 100644
--- a/tests/unit/onyxCacheTest.js
+++ b/tests/unit/onyxCacheTest.js
@@ -347,6 +347,18 @@ describe('Onyx', () => {
                 expect(() => cache.merge(0)).toThrow();
                 expect(() => cache.merge({})).not.toThrow();
             });
+
+            it('Should merge `null` values', () => {
+                // `null` values can override existing values and should also
+                // be preserved during merges.
+                cache.set('mockKey', {ID: 5});
+                cache.set('mockNullKey', null);
+
+                cache.merge({mockKey: null});
+
+                expect(cache.getValue('mockKey')).toEqual(null);
+                expect(cache.getValue('mockNullKey')).toEqual(null);
+            });
         });
 
         describe('hasPendingTask', () => {