From 915d8152542f45bd197965147fff65807393e7f7 Mon Sep 17 00:00:00 2001
From: Perry Fraser <perryprog@users.noreply.github.com>
Date: Mon, 11 Aug 2025 18:44:10 -0400
Subject: [PATCH] feat: make ReagentId hash by value (#39494)

---
 Content.Shared/Chemistry/Reagent/ReagentId.cs | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Content.Shared/Chemistry/Reagent/ReagentId.cs b/Content.Shared/Chemistry/Reagent/ReagentId.cs
index 798dd28db4..88c0abff2a 100644
--- a/Content.Shared/Chemistry/Reagent/ReagentId.cs
+++ b/Content.Shared/Chemistry/Reagent/ReagentId.cs
@@ -75,7 +75,21 @@ public partial struct ReagentId : IEquatable<ReagentId>
 
     public override int GetHashCode()
     {
-        return HashCode.Combine(Prototype, Data);
+        // We need to make sure we take the hash code of Data by value in order
+        // for hashed key lookups to work properly
+        var hash = 17;
+        unchecked
+        {
+            if (Data?.Count != 0)
+            {
+                foreach (var data in Data ?? [])
+                {
+                    hash = hash * 23 + data.GetHashCode();
+                }
+            }
+        }
+
+        return HashCode.Combine(Prototype, hash);
     }
 
     public string ToString(FixedPoint2 quantity)
-- 
2.51.2