From b648e4f86df6208033951180fc12d8210b5b898b Mon Sep 17 00:00:00 2001
From: ReinforceZwei <39955851+ReinforceZwei@users.noreply.github.com>
Date: Tue, 25 Aug 2020 04:38:08 +0800
Subject: [PATCH] Fix crash on custom item IDs from Forge servers (#1233)

* Fix unknown item id cause crashes for handling non-vanilla item (i.e. forge item)
* Add Unknown item type and use ItemType.Unknown for unknown items
Co-authored-by: ORelio <ORelio@users.noreply.github.com>
---
 MinecraftClient/Inventory/ItemPalettes/ItemPalette.cs | 9 +++++++--
 MinecraftClient/Inventory/ItemType.cs                 | 3 ++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/MinecraftClient/Inventory/ItemPalettes/ItemPalette.cs b/MinecraftClient/Inventory/ItemPalettes/ItemPalette.cs
index 76edb098..54afe69b 100644
--- a/MinecraftClient/Inventory/ItemPalettes/ItemPalette.cs
+++ b/MinecraftClient/Inventory/ItemPalettes/ItemPalette.cs
@@ -15,17 +15,22 @@ namespace MinecraftClient.Inventory.ItemPalettes
             // Index reverse mappings for use in ToId()
             foreach (KeyValuePair<int, ItemType> entry in GetDict())
                 DictReverse.Add(entry.Value, entry.Key);
+
+            DictReverse[ItemType.Unknown] = -2;
+            DictReverse[ItemType.Null] = -1;
         }
 
         public ItemType FromId(int id)
         {
+            // Unknown item types may appear of Forge servers for custom items
+            if (!GetDict().ContainsKey(id))
+                return ItemType.Unknown;
+
             return GetDict()[id];
         }
 
         public int ToId(ItemType itemType)
         {
-            if (itemType == ItemType.Null)
-                return -1;
             return DictReverse[itemType];
         }
     }
diff --git a/MinecraftClient/Inventory/ItemType.cs b/MinecraftClient/Inventory/ItemType.cs
index 10b6ac8b..ed37efff 100644
--- a/MinecraftClient/Inventory/ItemType.cs
+++ b/MinecraftClient/Inventory/ItemType.cs
@@ -12,7 +12,8 @@ namespace MinecraftClient.Inventory
     /// </summary>
     public enum ItemType
     {
-        Null = -1, // Unspecified item type
+        Unknown = -2, // Unsupported item type (Forge mod custom item...)
+        Null = -1,    // Unspecified item type (Used in the network protocol)
 
         AcaciaBoat,
         AcaciaButton,