From f0c26d5967b20b59b0a1b523d291fa92d180247b Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Sun, 16 Jun 2024 10:19:50 +0200
Subject: [PATCH] Make sure we actually have block mappings before trying to
 apply them

---
 .../rewriter/StructuredItemRewriter.java      | 22 +++++++++++++------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/common/src/main/java/com/viaversion/viaversion/rewriter/StructuredItemRewriter.java b/common/src/main/java/com/viaversion/viaversion/rewriter/StructuredItemRewriter.java
index fc4160a7a..e57be372e 100644
--- a/common/src/main/java/com/viaversion/viaversion/rewriter/StructuredItemRewriter.java
+++ b/common/src/main/java/com/viaversion/viaversion/rewriter/StructuredItemRewriter.java
@@ -86,7 +86,13 @@ public class StructuredItemRewriter<C extends ClientboundPacketType, S extends S
             }
         }
 
-        updateItemComponents(connection, dataContainer, this::handleItemToClient, mappingData != null ? mappingData::getNewItemId : null, mappingData != null ? mappingData::getNewBlockId : null);
+        Int2IntFunction itemIdRewriter = null;
+        Int2IntFunction blockIdRewriter = null;
+        if (mappingData != null) {
+            itemIdRewriter = mappingData.getItemMappings() != null ? mappingData::getNewItemId : null;
+            blockIdRewriter = mappingData.getBlockMappings() != null ? mappingData::getNewBlockId : null;
+        }
+        updateItemComponents(connection, dataContainer, this::handleItemToClient, itemIdRewriter, blockIdRewriter);
         return item;
     }
 
@@ -111,13 +117,15 @@ public class StructuredItemRewriter<C extends ClientboundPacketType, S extends S
         }
 
         restoreTextComponents(item);
-        updateItemComponents(connection, dataContainer, this::handleItemToServer, mappingData != null ? mappingData::getOldItemId : null, mappingData != null ? mappingData::getOldBlockId : null);
-        return item;
-    }
 
-    // Temporary
-    protected void updateItemComponents(UserConnection connection, StructuredDataContainer container, ItemHandler itemHandler, @Nullable Int2IntFunction idRewriter) {
-        updateItemComponents(connection, container, itemHandler, idRewriter, 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;
     }
 
     protected void updateItemComponents(UserConnection connection, StructuredDataContainer container, ItemHandler itemHandler, @Nullable Int2IntFunction idRewriter, @Nullable Int2IntFunction blockIdRewriter) {