[1.16.4] onBlockAdded being called twice on server side

I have a block, and I want to do some logic when it is added to the world.

I am using the onBlockAdded method to accomplish this.

However, the method is being called twice, and I'm not sure why.

Minmum reproduction using the examplemod from `forge-1.16.4-35.1.0-mdk`

ExampleMod.java

package com.example.examplemod;

import net.minecraft.block.AbstractBlock;
import net.minecraft.block.Block;
import net.minecraft.block.Blocks;
import net.minecraft.block.material.Material;
import net.minecraft.item.BlockItem;
import net.minecraft.item.Item;
import net.minecraft.item.ItemGroup;
import net.minecraft.item.ItemStack;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.event.RegistryEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.InterModComms;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent;
import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
import net.minecraftforge.fml.event.lifecycle.InterModEnqueueEvent;
import net.minecraftforge.fml.event.lifecycle.InterModProcessEvent;
import net.minecraftforge.fml.event.server.FMLServerStartingEvent;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
import net.minecraftforge.registries.ObjectHolder;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.stream.Collectors;

// The value here should match an entry in the META-INF/mods.toml file
@Mod("examplemod")
public class ExampleMod
{
    // Directly reference a log4j logger.
    private static final Logger LOGGER = LogManager.getLogger();

    public ExampleMod() {
        // Register the setup method for modloading
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::setup);
        // Register the enqueueIMC method for modloading
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::enqueueIMC);
        // Register the processIMC method for modloading
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::processIMC);
        // Register the doClientStuff method for modloading
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::doClientStuff);

        // Register ourselves for server and other game events we are interested in
        MinecraftForge.EVENT_BUS.register(this);
    }

    private void setup(final FMLCommonSetupEvent event)
    {
        // some preinit code
        LOGGER.info("HELLO FROM PREINIT");
    }

    private void doClientStuff(final FMLClientSetupEvent event) {
        // do something that can only be done on the client
        LOGGER.info("Got game settings {}", event.getMinecraftSupplier().get().gameSettings);
    }

    private void enqueueIMC(final InterModEnqueueEvent event)
    {
        // some example code to dispatch IMC to another mod
        InterModComms.sendTo("examplemod", "helloworld", () -> { LOGGER.info("Hello world from the MDK"); return "Hello world";});
    }

    private void processIMC(final InterModProcessEvent event)
    {
        // some example code to receive and process InterModComms from other mods
        LOGGER.info("Got IMC {}", event.getIMCStream().
                map(m->m.getMessageSupplier().get()).
                collect(Collectors.toList()));
    }
    // You can use SubscribeEvent and let the Event Bus discover methods to call
    @SubscribeEvent
    public void onServerStarting(FMLServerStartingEvent event) {
        // do something when the server starts
        LOGGER.info("HELLO from server starting");
    }

    @ObjectHolder("examplemod")
    public static final class Blocks {
        public static final Block EXAMPLEBLOCK = null;
    }

    // You can use EventBusSubscriber to automatically subscribe events on the contained class (this is subscribing to the MOD
    // Event bus for receiving Registry Events)
    @Mod.EventBusSubscriber(bus=Mod.EventBusSubscriber.Bus.MOD)
    public static class RegistryEvents {
        @SubscribeEvent
        public static void onBlocksRegistry(final RegistryEvent.Register<Block> blockRegistryEvent) {
            // register a new block here
            LOGGER.info("HELLO from Register Block");
            blockRegistryEvent.getRegistry().register(
                new ExampleBlock(AbstractBlock.Properties.create(Material.IRON)).setRegistryName("examplemod","exampleblock")
            );
        }
        @SubscribeEvent
        public static void onRegisterItems(final RegistryEvent.Register<Item> e) {
            Item item = new BlockItem(Blocks.EXAMPLEBLOCK, new Item.Properties().group(new ItemGroup(-1, "examplegroup"){
                @Override
                public ItemStack createIcon() {
                    return new ItemStack(Blocks.EXAMPLEBLOCK);
                }
            })).setRegistryName("examplemod","exampleblock");
            e.getRegistry().register(item);
        }
    }
}

ExampleBlock.java

package com.example.examplemod;

import net.minecraft.block.Block;
import net.minecraft.block.BlockState;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.World;

public class ExampleBlock extends Block {

	public ExampleBlock(Properties properties) {
		super(properties);
	}

	@Override
	public void onBlockAdded(
		BlockState state, World worldIn, BlockPos pos, BlockState oldState, boolean isMoving
	) {
		super.onBlockAdded(state, worldIn, pos, oldState, isMoving);
		System.out.println("ADDED! " + worldIn.isRemote);
	}
}

Right clicking once places the block in the world as expected

However, the method is being called twice.
[02:40:40] [Server thread/INFO] [STDOUT/]: [com.example.examplemod.ExampleBlock:onBlockAdded:19]: ADDED! false
[02:40:40] [Server thread/INFO] [STDOUT/]: [com.example.examplemod.ExampleBlock:onBlockAdded:19]: ADDED! false

Stack from the first call:

onBlockAdded:18, ExampleBlock (com.example.examplemod)
onBlockAdded:702, AbstractBlock$AbstractBlockState (net.minecraft.block)
setBlockState:285, Chunk (net.minecraft.world.chunk)
setBlockState:228, World (net.minecraft.world)
setBlockState:205, World (net.minecraft.world)
placeBlock:152, BlockItem (net.minecraft.item)
tryPlace:57, BlockItem (net.minecraft.item)
onItemUse:42, BlockItem (net.minecraft.item)
onPlaceItemIntoWorld:607, ForgeHooks (net.minecraftforge.common)
onItemUse:191, ItemStack (net.minecraft.item)
func_219441_a:359, PlayerInteractionManager (net.minecraft.server.management)
processTryUseItemOnBlock:986, ServerPlayNetHandler (net.minecraft.network.play)
processPacket:45, CPlayerTryUseItemOnBlockPacket (net.minecraft.network.play.client)
processPacket:12, CPlayerTryUseItemOnBlockPacket (net.minecraft.network.play.client)
lambda$checkThreadAndEnqueue$0:19, PacketThreadUtil (net.minecraft.network)
run:-1, 1364657741 (net.minecraft.network.PacketThreadUtil$$Lambda$5784)
run:20, TickDelayedTask (net.minecraft.util.concurrent)
run:139, ThreadTaskExecutor (net.minecraft.util.concurrent)
run:22, RecursiveEventLoop (net.minecraft.util.concurrent)
run:758, MinecraftServer (net.minecraft.server)
run:159, MinecraftServer (net.minecraft.server)
driveOne:109, ThreadTaskExecutor (net.minecraft.util.concurrent)
driveOneInternal:741, MinecraftServer (net.minecraft.server)
driveOne:735, MinecraftServer (net.minecraft.server)
driveUntil:122, ThreadTaskExecutor (net.minecraft.util.concurrent)
runScheduledTasks:721, MinecraftServer (net.minecraft.server)
func_240802_v_:667, MinecraftServer (net.minecraft.server)
lambda$startServer$0:233, MinecraftServer (net.minecraft.server)
run:-1, 830477086 (net.minecraft.server.MinecraftServer$$Lambda$5086)
run:748, Thread (java.lang)

Stack from the second call:

onBlockAdded:18, ExampleBlock (com.example.examplemod)
onBlockAdded:702, AbstractBlock$AbstractBlockState (net.minecraft.block)
onPlaceItemIntoWorld:666, ForgeHooks (net.minecraftforge.common)
onItemUse:191, ItemStack (net.minecraft.item)
func_219441_a:359, PlayerInteractionManager (net.minecraft.server.management)
processTryUseItemOnBlock:986, ServerPlayNetHandler (net.minecraft.network.play)
processPacket:45, CPlayerTryUseItemOnBlockPacket (net.minecraft.network.play.client)
processPacket:12, CPlayerTryUseItemOnBlockPacket (net.minecraft.network.play.client)
lambda$checkThreadAndEnqueue$0:19, PacketThreadUtil (net.minecraft.network)
run:-1, 1364657741 (net.minecraft.network.PacketThreadUtil$$Lambda$5784)
run:20, TickDelayedTask (net.minecraft.util.concurrent)
run:139, ThreadTaskExecutor (net.minecraft.util.concurrent)
run:22, RecursiveEventLoop (net.minecraft.util.concurrent)
run:758, MinecraftServer (net.minecraft.server)
run:159, MinecraftServer (net.minecraft.server)
driveOne:109, ThreadTaskExecutor (net.minecraft.util.concurrent)
driveOneInternal:741, MinecraftServer (net.minecraft.server)
driveOne:735, MinecraftServer (net.minecraft.server)
driveUntil:122, ThreadTaskExecutor (net.minecraft.util.concurrent)
runScheduledTasks:721, MinecraftServer (net.minecraft.server)
func_240802_v_:667, MinecraftServer (net.minecraft.server)
lambda$startServer$0:233, MinecraftServer (net.minecraft.server)
run:-1, 830477086 (net.minecraft.server.MinecraftServer$$Lambda$5086)
run:748, Thread (java.lang)

Being in survival mode exhibits the same behaviour.

Am I registering something wrong?

Failing to implement some method that has been unnecessary until I wanted to override onBlockAdded?

Is it actually deprecated in favour of a separate method, or is it just "minecraft deprecated"?

I'd appreciate any insights, thank you.

ExampleBlock.java ExampleMod.java

Edited January 18, 20214 yr by TeamDman
typo in title