fix: 1344 dupe fix refactor

EXILED/Exiled.Events/Handlers/Internal/Round.cs

@@ -82,7 +82,7 @@ public static void OnRestartingRound()
         /// <inheritdoc cref="Handlers.Player.OnChangingRole(ChangingRoleEventArgs)" />
         public static void OnChangingRole(ChangingRoleEventArgs ev)
         {
-            if (!ev.Player.IsHost && ev.NewRole == RoleTypeId.Spectator && ev.Reason is not(SpawnReason.Destroyed or SpawnReason.Died) && Events.Instance.Config.ShouldDropInventory)
+            if (!ev.Player.IsHost && ev.NewRole == RoleTypeId.Spectator && ev.Reason is not SpawnReason.Destroyed && Events.Instance.Config.ShouldDropInventory)
                 ev.Player.Inventory.ServerDropEverything();
         }
 

EXILED/Exiled.Events/Patches/Fixes/Fix1344Dupe.cs

@@ -0,0 +1,63 @@
+// -----------------------------------------------------------------------
+// <copyright file="Fix1344Dupe.cs" company="ExMod Team">
+// Copyright (c) ExMod Team. All rights reserved.
+// Licensed under the CC BY-SA 3.0 license.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Exiled.Events.Patches.Fixes
+{
+    using System.Collections.Generic;
+    using System.Reflection.Emit;
+
+    using Exiled.API.Features.Pools;
+    using HarmonyLib;
+    using InventorySystem;
+    using InventorySystem.Items;
+    using InventorySystem.Items.Usables.Scp1344;
+
+    using static HarmonyLib.AccessTools;
+
+    /// <summary>
+    /// Patches the <see cref="Scp1344Item.OnPlayerInventoryDropped"/> method.
+    /// Fixes the dupe where 2 copies of SCP-1344 can be created when a player dies.
+    /// Bug not reported to NW yet (rare in vanilla servers).
+    /// </summary>
+    [HarmonyPatch(typeof(Scp1344Item), nameof(Scp1344Item.OnPlayerInventoryDropped))]
+    public class Fix1344Dupe
+    {
+        private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, ILGenerator generator)
+        {
+            List<CodeInstruction> newInstructions = ListPool<CodeInstruction>.Pool.Get(instructions);
+
+            Label returnLabel = generator.DefineLabel();
+
+            newInstructions[newInstructions.Count - 1].labels.Add(returnLabel);
+
+            int offset = 1;
+            int index = newInstructions.FindIndex(x => x.opcode == OpCodes.Ret) + offset;
+
+            newInstructions.InsertRange(index, new[]
+            {
+                // this.OwnerInventory.UserInventory.Items
+                new CodeInstruction(OpCodes.Ldarg_0).MoveLabelsFrom(newInstructions[index]),
+                new(OpCodes.Callvirt, PropertyGetter(typeof(Scp1344Item), nameof(Scp1344Item.OwnerInventory))),
+                new(OpCodes.Ldfld, Field(typeof(Inventory), nameof(Inventory.UserInventory))),
+                new(OpCodes.Ldfld, Field(typeof(InventoryInfo), nameof(InventoryInfo.Items))),
+
+                // this.ItemSerial
+                new(OpCodes.Ldarg_0),
+                new(OpCodes.Callvirt, PropertyGetter(typeof(Scp1344Item), nameof(Scp1344Item.ItemSerial))),
+
+                // if (!this.OwnerInventory.UserInventory.Items.ContainsKey(this.ItemSerial) return;
+                new(OpCodes.Callvirt, Method(typeof(Dictionary<ushort, ItemBase>), nameof(Dictionary<ushort, ItemBase>.ContainsKey))),
+                new(OpCodes.Brfalse_S, returnLabel),
+            });
+
+            for (int z = 0; z < newInstructions.Count; z++)
+                yield return newInstructions[z];
+
+            ListPool<CodeInstruction>.Pool.Return(newInstructions);
+        }
+    }
+}