Force barrel minecarts to properly sync their stored fluid when acces…

…sed by capabilities

src/main/java/blusunrize/immersiveengineering/common/entities/BarrelMinecartEntity.java

@@ -26,13 +26,17 @@
 import net.minecraft.world.level.block.state.BlockState;
 import net.neoforged.neoforge.capabilities.Capabilities.FluidHandler;
 import net.neoforged.neoforge.capabilities.RegisterCapabilitiesEvent;
+import net.neoforged.neoforge.fluids.FluidStack;
 import net.neoforged.neoforge.fluids.FluidUtil;
+import net.neoforged.neoforge.fluids.capability.IFluidHandler;
 
 import javax.annotation.Nonnull;
 import java.util.function.Supplier;
 
 public class BarrelMinecartEntity extends IEMinecartEntity<WoodenBarrelBlockEntity>
 {
+	public MinecartFluidHandler minecartFluidHandler = new MinecartFluidHandler(this);
+
 	public BarrelMinecartEntity(Level world, double x, double y, double z)
 	{
 		this(IEEntityTypes.BARREL_MINECART.get(), world, x, y, z);
@@ -51,7 +55,7 @@ public BarrelMinecartEntity(EntityType<?> type, Level world)
 	public static <T extends BarrelMinecartEntity>
 	void registerCapabilities(RegisterCapabilitiesEvent ev, Supplier<EntityType<T>> type)
 	{
-		ev.registerEntity(FluidHandler.ENTITY, type.get(), (e, $) -> e.containedBlockEntity.tank);
+		ev.registerEntity(FluidHandler.ENTITY, type.get(), (e, $) -> e.minecartFluidHandler);
 	}
 
 	@Override
@@ -102,4 +106,67 @@ public BlockState getDisplayBlockState()
 		return IEBlocks.WoodenDevices.WOODEN_BARREL.defaultBlockState();
 	}
 
+
+	static class MinecartFluidHandler implements IFluidHandler
+	{
+		final BarrelMinecartEntity minecart;
+
+		public MinecartFluidHandler(BarrelMinecartEntity minecart)
+		{
+			this.minecart = minecart;
+		}
+
+		@Override
+		public int getTanks()
+		{
+			return 1;
+		}
+
+		@Override
+		public FluidStack getFluidInTank(int tank)
+		{
+			return this.minecart.containedBlockEntity.tank.getFluidInTank(tank);
+		}
+
+		@Override
+		public int getTankCapacity(int tank)
+		{
+			return this.minecart.containedBlockEntity.tank.getTankCapacity(tank);
+		}
+
+		@Override
+		public boolean isFluidValid(int tank, FluidStack stack)
+		{
+			return this.minecart.containedBlockEntity.tank.isFluidValid(tank, stack);
+		}
+
+		@Override
+		public int fill(FluidStack resource, FluidAction action)
+		{
+			int filled = this.minecart.containedBlockEntity.tank.fill(resource, action);
+			updateContainingEntity();
+			return filled;
+		}
+
+		@Override
+		public FluidStack drain(FluidStack resource, FluidAction action)
+		{
+			FluidStack drained = this.minecart.containedBlockEntity.tank.drain(resource, action);
+			updateContainingEntity();
+			return drained;
+		}
+
+		@Override
+		public FluidStack drain(int maxDrain, FluidAction action)
+		{
+			FluidStack drained = this.minecart.containedBlockEntity.tank.drain(maxDrain, action);
+			updateContainingEntity();
+			return drained;
+		}
+
+		private void updateContainingEntity()
+		{
+			this.minecart.updateSynchedData();
+		}
+	}
 }

src/main/java/blusunrize/immersiveengineering/common/entities/IEMinecartEntity.java

@@ -12,6 +12,9 @@
 import blusunrize.immersiveengineering.common.blocks.IEBlockInterfaces.IComparatorOverride;
 import blusunrize.immersiveengineering.common.blocks.IEBlockInterfaces.IInteractionObjectIE;
 import net.minecraft.nbt.CompoundTag;
+import net.minecraft.network.syncher.EntityDataAccessor;
+import net.minecraft.network.syncher.EntityDataSerializers;
+import net.minecraft.network.syncher.SynchedEntityData;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.InteractionHand;
 import net.minecraft.world.InteractionResult;
@@ -36,6 +39,7 @@
 
 public abstract class IEMinecartEntity<T extends BlockEntity> extends AbstractMinecart implements MenuProvider
 {
+	private static final EntityDataAccessor<CompoundTag> DATA_ID_BE_DATA = SynchedEntityData.defineId(IEMinecartEntity.class, EntityDataSerializers.COMPOUND_TAG);
 	protected T containedBlockEntity;
 
 	protected IEMinecartEntity(EntityType<?> type, Level world, double x, double y, double z)
@@ -114,6 +118,14 @@ public AbstractContainerMenu createMenu(int id, @Nonnull Inventory playerInvento
 		return null;
 	}
 
+	@Override
+	protected void defineSynchedData()
+	{
+		super.defineSynchedData();
+		this.entityData.define(DATA_ID_BE_DATA, new CompoundTag());
+	}
+
+
 	@Override
 	protected void addAdditionalSaveData(@Nonnull CompoundTag compound)
 	{
@@ -131,6 +143,20 @@ protected void readAdditionalSaveData(@Nonnull CompoundTag compound)
 		super.readAdditionalSaveData(compound);
 		this.containedBlockEntity = getTileProvider().get();
 		this.containedBlockEntity.load(compound);
+		this.updateSynchedData();
+	}
+
+	public void updateSynchedData()
+	{
+		this.getEntityData().set(DATA_ID_BE_DATA, this.containedBlockEntity.saveWithoutMetadata());
+	}
+
+	@Override
+	public void onSyncedDataUpdated(EntityDataAccessor<?> p_38527_)
+	{
+		super.onSyncedDataUpdated(p_38527_);
+		if(DATA_ID_BE_DATA.equals(p_38527_))
+			this.containedBlockEntity.load(this.getEntityData().get(DATA_ID_BE_DATA));
 	}
 
 	// This is only used by the super impl of destroy, which does not allow attaching NBT to the drop. So it's actually