Cleanup and catch some NPE

src/main/java/net/minestom/server/instance/Instance.java

@@ -676,6 +676,7 @@ public abstract class Instance implements BlockModifier, EventHandler, DataConta
         blockActionPacket.blockId = block.getBlockId();
 
         final Chunk chunk = getChunkAt(blockPosition);
+        Check.notNull(chunk, "The chunk at " + blockPosition + " is not loaded!");
         chunk.sendPacketToViewers(blockActionPacket);
     }
 

src/main/java/net/minestom/server/instance/InstanceContainer.java

@@ -107,8 +107,9 @@ public class InstanceContainer extends Instance {
     }
 
     @Override
-    public void setCustomBlock(int x, int y, int z, short customBlockId, Data data) {
+    public void setCustomBlock(int x, int y, int z, short customBlockId, @Nullable Data data) {
         final CustomBlock customBlock = BLOCK_MANAGER.getCustomBlock(customBlockId);
+        Check.notNull(customBlock, "The custom block with the id " + customBlockId + " does not exist.");
         setBlock(x, y, z, customBlock.getDefaultBlockStateId(), customBlock, data);
     }
 
@@ -136,13 +137,11 @@ public class InstanceContainer extends Instance {
         if (ChunkUtils.isLoaded(chunk)) {
             UNSAFE_setBlock(chunk, x, y, z, blockStateId, customBlock, data);
         } else {
-            if (hasEnabledAutoChunkLoad()) {
+            Check.stateCondition(!hasEnabledAutoChunkLoad(),
-                final int chunkX = ChunkUtils.getChunkCoordinate(x);
+                    "Tried to set a block to an unloaded chunk with auto chunk load disabled");
-                final int chunkZ = ChunkUtils.getChunkCoordinate(z);
+            final int chunkX = ChunkUtils.getChunkCoordinate(x);
-                loadChunk(chunkX, chunkZ, c -> UNSAFE_setBlock(c, x, y, z, blockStateId, customBlock, data));
+            final int chunkZ = ChunkUtils.getChunkCoordinate(z);
-            } else {
+            loadChunk(chunkX, chunkZ, c -> UNSAFE_setBlock(c, x, y, z, blockStateId, customBlock, data));
-                throw new IllegalStateException("Tried to set a block to an unloaded chunk with auto chunk load disabled");
-            }
         }
     }
 
@@ -159,7 +158,8 @@ public class InstanceContainer extends Instance {
      * @param customBlock  the {@link CustomBlock}, null if none
      * @param data         the {@link Data}, null if none
      */
-    private void UNSAFE_setBlock(Chunk chunk, int x, int y, int z, short blockStateId, CustomBlock customBlock, Data data) {
+    private void UNSAFE_setBlock(@NotNull Chunk chunk, int x, int y, int z, short blockStateId,
+                                 @Nullable CustomBlock customBlock, @Nullable Data data) {
         if (chunk.isReadOnly()) {
             return;
         }
@@ -216,7 +216,7 @@ public class InstanceContainer extends Instance {
         }
     }
 
-    private void setAlreadyChanged(BlockPosition blockPosition, short blockStateId) {
+    private void setAlreadyChanged(@NotNull BlockPosition blockPosition, short blockStateId) {
         currentlyChangingBlocks.put(blockPosition, Block.fromStateId(blockStateId));
     }
 
@@ -228,7 +228,7 @@ public class InstanceContainer extends Instance {
      * @param blockStateId  the block state id
      * @return true if the block changed since the last update
      */
-    private boolean isAlreadyChanged(BlockPosition blockPosition, short blockStateId) {
+    private boolean isAlreadyChanged(@NotNull BlockPosition blockPosition, short blockStateId) {
         final Block changedBlock = currentlyChangingBlocks.get(blockPosition);
         if (changedBlock == null)
             return false;
@@ -257,7 +257,7 @@ public class InstanceContainer extends Instance {
      * @param previousBlock the block which has been destroyed
      * @param blockPosition the block position
      */
-    private void callBlockDestroy(Chunk chunk, int index, CustomBlock previousBlock, BlockPosition blockPosition) {
+    private void callBlockDestroy(@NotNull Chunk chunk, int index, @NotNull CustomBlock previousBlock, @NotNull BlockPosition blockPosition) {
         final Data previousData = chunk.getBlockData(index);
         previousBlock.onDestroy(this, blockPosition, previousData);
     }
@@ -271,7 +271,7 @@ public class InstanceContainer extends Instance {
      * @param index         the block index
      * @param blockPosition the block position
      */
-    private void callBlockPlace(Chunk chunk, int index, BlockPosition blockPosition) {
+    private void callBlockPlace(@NotNull Chunk chunk, int index, @NotNull BlockPosition blockPosition) {
         final CustomBlock actualBlock = chunk.getCustomBlock(index);
         if (actualBlock == null)
             return;
@@ -286,7 +286,7 @@ public class InstanceContainer extends Instance {
      * @param blockPosition the block position
      * @return the modified block state id
      */
-    private short executeBlockPlacementRule(short blockStateId, BlockPosition blockPosition) {
+    private short executeBlockPlacementRule(short blockStateId, @NotNull BlockPosition blockPosition) {
         final BlockPlacementRule blockPlacementRule = BLOCK_MANAGER.getBlockPlacementRule(blockStateId);
         if (blockPlacementRule != null) {
             return blockPlacementRule.blockRefresh(this, blockPosition, blockStateId);

src/main/java/net/minestom/server/instance/block/BlockManager.java

@@ -2,6 +2,8 @@ package net.minestom.server.instance.block;
 
 import net.minestom.server.instance.block.rule.BlockPlacementRule;
 import net.minestom.server.utils.validate.Check;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -23,7 +25,7 @@ public class BlockManager {
      * @throws IllegalArgumentException if <code>customBlock</code> block id is not greater than 0
      * @throws IllegalStateException    if the id of <code>customBlock</code> is already registered
      */
-    public void registerCustomBlock(CustomBlock customBlock) {
+    public void registerCustomBlock(@NotNull CustomBlock customBlock) {
         final short id = customBlock.getCustomBlockId();
         Check.argCondition(id <= 0, "Custom block ID must be greater than 0, got: " + id);
         Check.stateCondition(customBlocksInternalId[id] != null, "a CustomBlock with the id " + id + " already exists");
@@ -39,7 +41,7 @@ public class BlockManager {
      * @param blockPlacementRule the block placement rule to register
      * @throws IllegalArgumentException if <code>blockPlacementRule</code> block id is negative
      */
-    public void registerBlockPlacementRule(BlockPlacementRule blockPlacementRule) {
+    public void registerBlockPlacementRule(@NotNull BlockPlacementRule blockPlacementRule) {
         final short id = blockPlacementRule.getBlockId();
         Check.argCondition(id < 0, "Block ID must be >= 0, got: " + id);
 
@@ -52,7 +54,8 @@ public class BlockManager {
      * @param block the block to check
      * @return the block placement rule associated with the block, null if not any
      */
-    public BlockPlacementRule getBlockPlacementRule(Block block) {
+    @Nullable
+    public BlockPlacementRule getBlockPlacementRule(@NotNull Block block) {
         return this.placementRules[block.getBlockId()];
     }
 
@@ -62,6 +65,7 @@ public class BlockManager {
      * @param blockStateId the block id to check
      * @return the block placement rule associated with the id, null if not any
      */
+    @Nullable
     public BlockPlacementRule getBlockPlacementRule(short blockStateId) {
         final Block block = Block.fromStateId(blockStateId); // Convert block alternative
         return getBlockPlacementRule(block);
@@ -73,7 +77,8 @@ public class BlockManager {
      * @param identifier the custom block identifier
      * @return the {@link CustomBlock} associated with the identifier, null if not any
      */
-    public CustomBlock getCustomBlock(String identifier) {
+    @Nullable
+    public CustomBlock getCustomBlock(@NotNull String identifier) {
         return customBlocksId.get(identifier);
     }
 
@@ -83,6 +88,7 @@ public class BlockManager {
      * @param id the custom block id
      * @return the {@link CustomBlock} associated with the id, null if not any
      */
+    @Nullable
     public CustomBlock getCustomBlock(short id) {
         return customBlocksInternalId[id];
     }

src/main/java/net/minestom/server/utils/chunk/ChunkUtils.java

@@ -7,6 +7,8 @@ import net.minestom.server.instance.Instance;
 import net.minestom.server.utils.BlockPosition;
 import net.minestom.server.utils.MathUtils;
 import net.minestom.server.utils.Position;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public final class ChunkUtils {
 
@@ -20,7 +22,7 @@ public final class ChunkUtils {
      * @param chunk the chunk to check
      * @return true if the chunk is loaded, false otherwise
      */
-    public static boolean isLoaded(Chunk chunk) {
+    public static boolean isLoaded(@Nullable Chunk chunk) {
         return chunk != null && chunk.isLoaded();
     }
 
@@ -32,7 +34,7 @@ public final class ChunkUtils {
      * @param z        instance Z coordinate
      * @return true if the chunk is loaded, false otherwise
      */
-    public static boolean isLoaded(Instance instance, float x, float z) {
+    public static boolean isLoaded(@NotNull Instance instance, float x, float z) {
         final int chunkX = getChunkCoordinate((int) x);
         final int chunkZ = getChunkCoordinate((int) z);
 
@@ -99,7 +101,8 @@ public final class ChunkUtils {
      * @param range    how far should it retrieves chunk
      * @return an array containing chunks index
      */
-    public static long[] getChunksInRange(final Position position, int range) {
+    @NotNull
+    public static long[] getChunksInRange(@NotNull Position position, int range) {
         range = range * 2;
         long[] visibleChunks = new long[MathUtils.square(range + 1)];
         final int startLoop = -(range / 2);
@@ -123,7 +126,8 @@ public final class ChunkUtils {
      * @param chunkZ   the chunk Z
      * @return an array containing all the loaded neighbours chunk index
      */
-    public static long[] getNeighbours(Instance instance, int chunkX, int chunkZ) {
+    @NotNull
+    public static long[] getNeighbours(@NotNull Instance instance, int chunkX, int chunkZ) {
         LongList chunks = new LongArrayList();
         // Constants used to loop through the neighbors
         final int[] posX = {1, 0, -1};
@@ -176,6 +180,7 @@ public final class ChunkUtils {
      * @param chunkZ the chunk Z
      * @return the instance position of the block located in {@code index}
      */
+    @NotNull
     public static BlockPosition getBlockPosition(int index, int chunkX, int chunkZ) {
         final int x = blockIndexToPositionX(index, chunkX);
         final int y = blockIndexToPositionY(index);