Do not create unnecessary tag

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/data/MappingData.java

@@ -15,8 +15,7 @@ import java.util.Map;
 
 public class MappingData {
     public static Map<Integer, Integer> oldToNewBlocks = new HashMap<>();
-    public static Map<Integer, Integer> oldToNewItems = new HashMap<>();
+    public static BiMap<Integer, Integer> oldToNewItems = HashBiMap.create();
-    public static Map<Integer, Integer> newToOldItems = new HashMap<>();
     public static Map<String, Integer[]> blockTags = new HashMap<>();
     public static Map<String, Integer[]> itemTags = new HashMap<>();
     public static Map<String, Integer[]> fluidTags = new HashMap<>();
@@ -32,8 +31,6 @@ public class MappingData {
         mapIdentifiers(oldToNewBlocks, mapping1_12.getAsJsonObject("blocks"), mapping1_13.getAsJsonObject("blocks"));
         System.out.println("Loading item mapping...");
         mapIdentifiers(oldToNewItems, mapping1_12.getAsJsonObject("items"), mapping1_13.getAsJsonObject("items"));
-        System.out.println("Loading new to old item mapping...");
-        mapIdentifiers(newToOldItems, mapping1_13.getAsJsonObject("items"), mapping1_12.getAsJsonObject("items"));
         System.out.println("Loading new tags...");
         loadTags(blockTags, mapping1_13.getAsJsonObject("block_tags"));
         loadTags(itemTags, mapping1_13.getAsJsonObject("item_tags"));

common/src/main/java/us/myles/ViaVersion/protocols/protocolsnapshotto1_12_2/packets/InventoryPackets.java

@@ -263,36 +263,33 @@ public class InventoryPackets {
     // TODO Rewrite identifiers
     public static void toClient(Item item) {
         if (item == null) return;
-
-        // create tag
         CompoundTag tag = item.getTag();
-        if (tag == null) {
-            item.setTag(tag = new CompoundTag("tag"));
-        }
 
         // Save original id
         int originalId = (item.getId() << 16 | item.getData() & 0xFFFF);
-        tag.put(new IntTag(NBT_TAG_NAME, originalId));
 
-        // NBT changes
+        // NBT Additions
         if (isDamageable(item.getId())) {
+            if (tag == null) item.setTag(tag = new CompoundTag("tag"));
             tag.put(new IntTag("Damage", item.getData()));
         }
-
         if (item.getId() == 358) { // map
+            if (tag == null) item.setTag(tag = new CompoundTag("tag"));
             tag.put(new IntTag("map", item.getData()));
         }
 
-        if (item.getId() == 442) { // shield
+        // NBT Changes
+        if (tag != null) {
+            // Invert shield color id
+            if (item.getId() == 442) {
                 if (tag.get("BlockEntityTag") instanceof CompoundTag) {
                     CompoundTag blockEntityTag = tag.get("BlockEntityTag");
                     if (blockEntityTag.get("Base") instanceof IntTag) {
                         IntTag base = blockEntityTag.get("Base");
-                    base.setValue(15 - base.getValue()); // invert color id
+                        base.setValue(15 - base.getValue());
                     }
                 }
             }
-
             // Display Name now uses JSON
             if (tag.get("display") instanceof CompoundTag) {
                 if (((CompoundTag) tag.get("display")).get("Name") instanceof StringTag) {
@@ -304,7 +301,6 @@ public class InventoryPackets {
                     );
                 }
             }
-
             // ench is now Enchantments and now uses identifiers
             if (tag.get("ench") instanceof ListTag) {
                 ListTag ench = tag.get("ench");
@@ -314,7 +310,7 @@ public class InventoryPackets {
                         CompoundTag enchantmentEntry = new CompoundTag("");
                         enchantmentEntry.put(new StringTag("id",
                                 MappingData.oldEnchantmentsIds.get(
-                                    (Short) ((CompoundTag) enchEntry).get("id").getValue()
+                                        (short) ((CompoundTag) enchEntry).get("id").getValue()
                                 )
                         ));
                         enchantmentEntry.put(new ShortTag("lvl", (Short) ((CompoundTag) enchEntry).get("lvl").getValue()));
@@ -324,6 +320,7 @@ public class InventoryPackets {
                 tag.remove("ench");
                 tag.put(enchantments);
             }
+        }
 
         int rawId = (item.getId() << 4 | item.getData() & 0xF);
 
@@ -345,7 +342,13 @@ public class InventoryPackets {
         }
 
         if (!MappingData.oldToNewItems.containsKey(rawId)) {
-            if (MappingData.oldToNewItems.containsKey(rawId & ~0xF)) {
+            if (!isDamageable(item.getId()) && item.getId() != 358) { // Map
+                if (tag == null) item.setTag(tag = new CompoundTag("tag"));
+                tag.put(new IntTag(NBT_TAG_NAME, originalId)); // Data will be lost, saving original id
+            }
+            if (item.getId() == 31 && item.getData() == 0) { // Shrub was removed
+                rawId = MappingData.oldToNewItems.get(512); // Dead Bush
+            } else if (MappingData.oldToNewItems.containsKey(rawId & ~0xF)) {
                 rawId &= ~0xF; // Remove data
             } else {
                 System.out.println("FAILED TO GET 1.13 ITEM FOR " + item.getId()); // TODO: Make this nicer etc, perhaps fix issues with mapping :T
@@ -378,7 +381,7 @@ public class InventoryPackets {
         }
 
         if (rawId == null) {
-            Integer oldId = MappingData.newToOldItems.get((int) item.getId());
+            Integer oldId = MappingData.oldToNewItems.inverse().get((int) item.getId());
             if (oldId != null) {
                 // Handle spawn eggs
                 Optional<String> eggEntityId = SpawnEggRewriter.getEntityId(oldId);

common/src/main/resources/assets/viaversion/data/mapping-1.12.json

@@ -204,7 +204,7 @@
     "476": "minecraft:sticky_piston[extended=true,facing=west]",
     "477": "minecraft:sticky_piston[extended=true,facing=east]",
     "480": "minecraft:cobweb",
-    "496": "minecraft:dead_bush",
+    //"496": "minecraft:dead_bush", RIP Dead Bush
     "497": "minecraft:grass",
     "498": "minecraft:fern",
     "512": "minecraft:dead_bush",