From 5b18ed714b2e0afb359b872a79b96610c9015c33 Mon Sep 17 00:00:00 2001
From: PaulusParssinen <paulus.parssinen@gmail.com>
Date: Tue, 30 Apr 2024 02:55:36 +0300
Subject: [PATCH] Hoist null check from loop in SortedSetObject.CopyDiff

* Just fast-path copy the entire set if the other dictionary is null
---
 .../server/Objects/SortedSet/SortedSetObject.cs | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/libs/server/Objects/SortedSet/SortedSetObject.cs b/libs/server/Objects/SortedSet/SortedSetObject.cs
index 49ba3de386..03225494d6 100644
--- a/libs/server/Objects/SortedSet/SortedSetObject.cs
+++ b/libs/server/Objects/SortedSet/SortedSetObject.cs
@@ -352,14 +352,17 @@ public override unsafe void Scan(long start, out List<byte[]> items, out long cu
         /// </summary>
         public static Dictionary<byte[], double> CopyDiff(Dictionary<byte[], double> dict1, Dictionary<byte[], double> dict2)
         {
-            Dictionary<byte[], double> result = new();
-            if (dict1 != null)
+            if (dict1 == null)
+                return [];
+
+            if (dict2 == null)
+                return new Dictionary<byte[], double>(dict1);
+
+            Dictionary<byte[], double> result = [];
+            foreach (var item in dict1)
             {
-                foreach (var item in dict1)
-                {
-                    if (dict2 == null || !dict2.ContainsKey(item.Key))
-                        result.Add(item.Key, item.Value);
-                }
+                if (!dict2.ContainsKey(item.Key))
+                    result.Add(item.Key, item.Value);
             }
             return result;
         }