From f91a25cba7fa2725b6ebe69ca6065076a8394603 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Sun, 16 Jun 2024 10:22:37 +0200
Subject: [PATCH] Make sure we have block mappings before trying to apply them

---
 .../BackwardsStructuredItemRewriter.java      | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/common/src/main/java/com/viaversion/viabackwards/api/rewriters/BackwardsStructuredItemRewriter.java b/common/src/main/java/com/viaversion/viabackwards/api/rewriters/BackwardsStructuredItemRewriter.java
index fe65e04a..b941ce31 100644
--- a/common/src/main/java/com/viaversion/viabackwards/api/rewriters/BackwardsStructuredItemRewriter.java
+++ b/common/src/main/java/com/viaversion/viabackwards/api/rewriters/BackwardsStructuredItemRewriter.java
@@ -34,6 +34,7 @@ import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
 import com.viaversion.viaversion.api.protocol.packet.ServerboundPacketType;
 import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.libs.fastutil.ints.Int2IntFunction;
 import com.viaversion.viaversion.rewriter.StructuredItemRewriter;
 import java.util.ArrayList;
 import java.util.List;
@@ -83,6 +84,13 @@ public class BackwardsStructuredItemRewriter<C extends ClientboundPacketType, S
             }
         }
 
+        Int2IntFunction itemIdRewriter = null;
+        Int2IntFunction blockIdRewriter = null;
+        if (mappingData != null) {
+            itemIdRewriter = mappingData.getItemMappings() != null ? mappingData::getNewItemId : null;
+            blockIdRewriter = mappingData.getBlockMappings() != null ? mappingData::getNewBlockId : null;
+        }
+
         final MappedItem mappedItem = mappingData != null ? mappingData.getMappedItem(item.identifier()) : null;
         if (mappedItem == null) {
             // Just rewrite the id
@@ -90,7 +98,7 @@ public class BackwardsStructuredItemRewriter<C extends ClientboundPacketType, S
                 item.setIdentifier(mappingData.getNewItemId(item.identifier()));
             }
 
-            updateItemComponents(connection, dataContainer, this::handleItemToClient, mappingData != null ? mappingData::getNewItemId : null, mappingData != null ? mappingData::getNewBlockId : null);
+            updateItemComponents(connection, dataContainer, this::handleItemToClient, itemIdRewriter, blockIdRewriter);
             return item;
         }
 
@@ -110,7 +118,7 @@ public class BackwardsStructuredItemRewriter<C extends ClientboundPacketType, S
             tag.putBoolean(nbtTagName("customName"), true);
         }
 
-        updateItemComponents(connection, dataContainer, this::handleItemToClient, mappingData::getNewItemId, mappingData::getNewBlockId);
+        updateItemComponents(connection, dataContainer, this::handleItemToClient, itemIdRewriter, blockIdRewriter);
         return item;
     }
 
@@ -144,7 +152,14 @@ public class BackwardsStructuredItemRewriter<C extends ClientboundPacketType, S
         }
 
         restoreTextComponents(item);
-        updateItemComponents(connection, dataContainer, this::handleItemToServer, mappingData != null ? mappingData::getOldItemId : null, mappingData != null ? mappingData::getOldBlockId : null);
+
+        Int2IntFunction itemIdRewriter = null;
+        Int2IntFunction blockIdRewriter = null;
+        if (mappingData != null) {
+            itemIdRewriter = mappingData.getItemMappings() != null ? mappingData::getOldItemId : null;
+            blockIdRewriter = mappingData.getBlockMappings() != null ? mappingData::getOldBlockId : null;
+        }
+        updateItemComponents(connection, dataContainer, this::handleItemToServer, itemIdRewriter, blockIdRewriter);
         return item;
     }