1.19.2 BlockEntity - onLoad() is called before NBT data can be copied over from BlockItem

[Povstalec]

I've got a BlockEntity, which can save its data to an item when broken(just like a Shulker Box). I use this to generate an "address" - When the BlockEntity is placed in the world for the first time, it will generate a new address and save the address to SavedData. When it is broken, the NBT data is saved to a BlockItem and the address is deleted from SavedData. When it is placed again, this time using the BlockItem that has data from the previous BlockEntity saved, it should copy the data and check if it has the address tag; if it does, it will save the address to SavedData again.

The last part used to work for me, but then I changed some things and forgot to make a backup, so it doesn't work properly now. What it does now is: The BlockEntity checks if there is an address tag, but there isn't one, so it generates a new address which it saves to SavedData. The address tag is then copied from the BlockItem immediately after, so when I click on it to see the address, the address is different from what is now saved in SavedData.

I'm pretty sure the problem lies in the fact that onLoad() is called before BlockItem NBT data is copied over. I'm using onLoad() to check whether or not it should generate an address and I know the BlockItem NBT data is stored correctly, because:
1. I'm saving more than just the address and everything else works perfectly and 2. the BlockEntity shows the correct address after I place it and click on it.

Is there a way to fix/work around this?

[warjort]

You won't get many responses if you don't show the code (preferably by posting it to github).

Just providing a description of what you think is happening vs what your code actually does is not very useful.

 

But, you know onLoad() gets called on both the client and the server? While the drops (if you are really doing it like it the shulker box) only happens on the server.

[Povstalec]

Block Entity code

SavedData code

Block code

6 hours ago, warjort said:

But, you know onLoad() gets called on both the client and the server? While the drops (if you are really doing it like it the shulker box) only happens on the server.

Yeah, I know, I'm making sure it only runs on server, so the problem can't be there.

[warjort]

From what I can tell, you won't be able to use onLoad() for this.

The issue is the block placement is done in 2 steps, see BlockItem.place()

(1) BlockItem.placeBlock() which sets the block in the world using normal logic,

(2) then it does updateBlockStateFromTag() and updateCustomBlockEntityTag() to change the state/blockentity to what is in the ItemStack. 

 

Your problem is step (1) ends up in LevelChunk.setBlockState() where it creates a default BlockEntity and then calls addAndRegisterBlockEntity() which calls onLoad()

This is before it has loaded the custom data from the ItemStack in updateCustomBlockEntityTag().

 

You either need to come up with different logic for your processing or add some code to your BlockEntity.load() to detect this happening.

 

For alternative logic, you should look at how mods like AE2, refined storage or one of the mods with pipes manage their (pipe) networks.

They probably don't store important keys/identifiers the way you are doing it?

[Povstalec]

Alright, thanks, that helped a lot.

It gave me the idea to extend the BlockItem class and add some stuff to updateCustomBlockEntityTag(), which now deletes the randomly generated address and replaces it with the one from the BlockItem. It's probably not the best way to go around it, but it does what I want for now. I'll probably come up with something better later down the line.