[Solved] [1.12] Exception while ticking a dispenser

[PegBeard]

I was messing around with dispenser behaviour and found that if the dispenser is replaced/destroyed/otherwise removed while dispensing, the game crashes with this in the log:

Spoiler

PM
Description: Exception while ticking a block

java.lang.IllegalArgumentException: Cannot get property PropertyDirection{name=facing, clazz=class net.minecraft.util.EnumFacing, values=[down, up, north, south, west, east]} as it does not exist in BlockStateContainer{block=minecraft:air, properties=[]}
    at net.minecraft.block.state.BlockStateContainer$StateImplementation.getValue(BlockStateContainer.java:204)
    at net.minecraft.dispenser.BehaviorDefaultDispenseItem.dispense(BehaviorDefaultDispenseItem.java:18)
    at net.minecraft.block.BlockDispenser.dispense(BlockDispenser.java:153)
    at net.minecraft.block.BlockDispenser.updateTick(BlockDispenser.java:189)
    at net.minecraft.world.WorldServer.tickUpdates(WorldServer.java:774)
    at net.minecraft.world.WorldServer.tick(WorldServer.java:231)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:825)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:740)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:589)
    at java.lang.Thread.run(Thread.java:748)

What happened to cause this is pretty simple - I made the dispensed stack cause an explosion, however, I get the same result if I set the dispenser to a different block (air, for example).
I have tried removing the tile entity before setting the block to air and/or causing the explosion, but the result is the same.

Is there any way I can prevent this crash, other than delaying the explosion?

Edited August 6, 2017 by PegBeard

[PegBeard]

I have a dispenser behaviour class, which is registered in the postInit:

 

Spoiler

public class DTDispensePowderKeg extends BehaviorDefaultDispenseItem
{
    @Override
	protected ItemStack dispenseStack(IBlockSource source, ItemStack stack)
    {
        World world = source.getWorld();
        BlockPos pos = source.getBlockPos();
        world.playSound((EntityPlayer)null, pos.getX(), pos.getY(), pos.getZ(), SoundEvents.ENTITY_TNT_PRIMED, SoundCategory.BLOCKS, 1.0F, 1.0F);
        stack.shrink(1);
        world.removeTileEntity(pos);
        world.isAirBlock(pos);
        world.newExplosion((EntityPlayer)null, pos.getX()+0.5D, pos.getY()+0.5D, pos.getZ()+0.5D, 4.0F, true, true);
        return stack;
    }
}

 

Is this correct? I looked it up back in 1.8, and assumed this was still relevant, as my other dispenser behaviours still work.

[PegBeard]

Oh. Is that something that changed since 1.8, or was the tutorial I followed back then wrong?

edit: the removeTileEntity was just testing for this issue, didn't intend to keep it.

Edited August 6, 2017 by PegBeard

[Draco18s]

11 minutes ago, PegBeard said:

Oh. Is that something that changed since 1.8, or was the tutorial I followed back then wrong?

Probably the latter.