[1.16] Tag Collection Empty When Connecting to Server

[Tikaji]

I noticed that when I am running a world locally that calling BlockTags.getCollection() will return a filled out collection of tags. However, when I attempt to connect to a server that the same call results in a collection that is empty. This is causing a null pointer exception (because the list is empty) in my mod when I attempt to fill out JEI recipes. I did notice that the BlockTag collection was being filled out on the server however.

I figured that these tags would be synced from server to client, but I think I'm wrong on that one. Any suggestions on what I should be doing so that I can access those tags from the server?

[ChampionAsh5357]

11 minutes ago, Tikaji said:

This is causing a null pointer exception (because the list is empty) in my mod when I attempt to fill out JEI recipes

Well that depends on how you are calling the tags. Recipes are not affected by block tags, only item tags. My guess is that you're calling the tags collections before they are initialized in the world.

[Tikaji]

That would make sense to me and upon further investigation, that seems to be the case. JEI runs and builds it's recipe list, and then the Tag Collections are created. I'm not sure if this is a question that the community here would be able to answer or if its something I should take to JEI, but since it seems to be the case that Tags are initialized after JEI runs, what is the best way to load in those recipes that allow for tags? Or perhaps I'm doing something else entirely wrong.

Link to JEI package in my repo if it helps: https://github.com/NovaMachina/ExNihiloSequentia/tree/1.16/src/main/java/com/novamachina/exnihilosequentia/common/compat/jei

[ChampionAsh5357]

7 minutes ago, Tikaji said:

I'm not sure if this is a question that the community here would be able to answer or if its something I should take to JEI, but since it seems to be the case that Tags are initialized after JEI runs, what is the best way to load in those recipes that allow for tags?

If I'm not mistaken, JEI does initialize recipes after the world loads up so it should be fine for tags. You just shouldn't have any direct references to tags in your code. They can be deserialized by the recipe itself.

[Tikaji]

Sorry, I should have stated that the normal crafting recipes work just fine, but custom recipes that I load from a JSON file do not. I had the thought that I should create custom recipe serializes and use a data pack. Would this potentially be the right route to solve my problem?

[ChampionAsh5357]

ITag<Item> itemTag = ItemTags.getCollection().get(entry);

Here is the issue I see. You will need to create recipes that deserialize on datapack load. Otherwise, this will return null or nothing since it hasn't been populated yet.

 

[Tikaji]

Ok, so If I am understanding correctly, in order for JEI to load correctly, I need to create recipes that will be available after datapack load. So, best course of action is to implement datapack support. Am I getting that right?

[ChampionAsh5357]

11 minutes ago, Tikaji said:

So, best course of action is to implement datapack support.

Yes, you would then be able to deserialize the instances correctly and on world load. If you really don't feel like it, you can also just add a reload listener to the server datapack and just refresh the data whenever that is loaded. Or, if you expect it to never change will ingame, I believe FMLServerStartedEvent is perfect for that.

Edited October 7, 2020 by ChampionAsh5357