Minecraft 1.21 bugfixes

src/main/java/config/Version.java

@@ -15,6 +15,7 @@ public enum Version {
     V1_20_2(764, 3578),
     V1_20_4(765, 3698),
     V1_20_6(766, 3839),
+    V1_21(767, 3953),
     ANY(0, 0);
 
     public final int dataVersion;

src/main/java/game/data/RenderDistanceExtender.java

@@ -88,6 +88,11 @@ public void updatePlayerPos(Coordinate2D newPos) {
         if (this.extendedDistance == 0) {
             return;
         }
+        // TODO: for 1.21, fix client unable to read chunk data packets generated by downloader for some reason
+        if (Config.versionReporter().isAtLeast(Version.V1_21)) {
+            return;
+        }
+
 
         int dist = this.extendedDistance;
         if (oldPos.isInRangeChebyshev(newChunkPos, 1)) {

src/main/java/game/data/WorldManager.java

@@ -604,6 +604,11 @@ public Set<Coordinate2D> sendChunksToPlayer(Collection<Coordinate2D> desired) {
             // send a packet with the chunk to the client
             Chunk chunk = chunkBinary.toChunk(withDim);
 
+            // skip chunks loaded in an earlier version
+            if (chunk.getDataVersion() != Config.versionReporter().getDataVersion()) {
+                continue;
+            }
+
             try {
                 PacketBuilder chunkData = chunk.toPacket();
                 PacketBuilder light = chunk.toLightPacket();

src/main/java/game/data/dimension/DimensionRegistry.java

@@ -141,7 +141,14 @@ private void readBiomes(ListTag biomeList) {
     }
 
     public Dimension getDimension(String name) {
-        return dimensions.get(name);
+        var dim = dimensions.get(name);
+
+        if (dim == null) {
+            System.out.println("Warning: Dimension " + name + " not found, using overworld");
+            return Dimension.OVERWORLD;
+        }
+
+        return dim;
     }
 
     /**

src/main/java/game/data/entity/specific/Villager.java

@@ -71,7 +71,7 @@ public void updateTrades(List<VillagerTrade> trades, int villagerLevel, int vill
     }
 
     private void addTradeNbtTags(CompoundTag root) {
-        if (trades == null || trades.size() == 0) {
+        if (trades == null || trades.isEmpty()) {
             return;
         }
 

src/main/java/game/data/villagers/VillagerManager.java

@@ -43,6 +43,12 @@ public void lastInteractedWith(DataTypeProvider provider) {
     }
 
     public void parseAndStoreVillagerTrade(DataTypeProvider provider) {
+        // TODO: villager trades cannot be saved since readSlot is broken in 1.20.2+ due to the
+        //  new item components
+        if (Config.versionReporter().isAtLeast(Version.V1_20_2)) {
+            return;
+        }
+
         if (lastInteractedWith == null) {
             return; // This should be impossible
         }

src/test/java/game/data/chunk/ChunkTest.java

@@ -48,6 +48,7 @@ private void testFor(int protocolVersion, String dataFile) throws IOException, C
         biomeMap.put("minecraft:badlands", new Biome(0));
         biomeMap.put("minecraft:forest", new Biome(1));
         biomeMap.put("minecraft:river", new Biome(2));
+        biomeMap.put("minecraft:plains", new Biome(3));
         when(codecMock.getBiomeRegistry()).thenReturn(new BiomeRegistry(biomeMap));
         when(mock.getDimensionRegistry()).thenReturn(codecMock);
 
@@ -184,4 +185,9 @@ void chunk_1_17() throws IOException, ClassNotFoundException {
     void chunk_1_19() throws IOException, ClassNotFoundException {
         testFor(Version.V1_19.protocolVersion, "chunkdata_1_19");
     }
+
+    @Test
+    void chunk_1_21() throws IOException, ClassNotFoundException {
+        testFor(Version.V1_21.protocolVersion, "chunkdata_1_21");
+    }
 }