Block placer causes NullPointerException for blocks using the placer entity

Minecraft version & Mod Version: Minecraft 1.12.2 Cyclic 1.15.12

Single player or Server: Server

Describe problem (what you were doing / what happened): A player on the server decided to put a market from Farming for Blockheads into a block placer, which relies on the placer entity to determine its direction. Because the block placer passes null, it causes a NullPointerException which crashes the server. When the server crashes, the block placer doesn’t remove the item from its inventory, so the server gets stuck crashing on startup.

Crash log (if any): crash-2018-06-27_10.19.25-server.txt

Time: 6/27/18 10:19 AM
Description: Ticking block entity

java.lang.NullPointerException: Ticking block entity
	at net.blay09.mods.farmingforblockheads.block.BlockMarket.func_180642_a(BlockMarket.java:83)
	at net.minecraft.block.Block.getStateForPlacement(Block.java:2238)
	at com.lothrazar.cyclicmagic.core.util.UtilPlaceBlocks.placeItemblock(UtilPlaceBlocks.java:95)
	at com.lothrazar.cyclicmagic.block.placer.TileEntityPlacer.func_73660_a(TileEntityPlacer.java:144)
	at net.minecraft.world.World.func_72939_s(World.java:1832)
	at net.minecraft.world.WorldServer.func_72939_s(WorldServer.java:613)
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:767)
	at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:396)
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526)
	at java.lang.Thread.run(Thread.java:748)

[BlayTheNinth]

Vanilla code is considered NonNull by default, with exceptions marked as @Nullable (though not in all cases, since they’ve only recently started doing that).

However, the fact that the Anvil also does not check for null is a clear indicator that this parameter is indeed NonNull and mods should not need to worry about null-checking the parameter.

From BlockAnvil, first line:

public IBlockState getStateForPlacement(World worldIn, BlockPos pos, EnumFacing facing, float hitX, float hitY, float hitZ, int meta, EntityLivingBase placer) {
        EnumFacing enumfacing = placer.getHorizontalFacing().rotateY();

For the fake player, check out FakePlayer or FakePlayerFactory classes, which are provided by Forge.

[Lothrazar]

https://minecraft.curseforge.com/projects/cyclic/files/2601662