Draco18s

Not true. Yes, you can do that, but it is not required. https://github.com/Draco18s/ReasonableRealism/blob/1.14.4/src/main/java/com/draco18s/harderores/HarderOres.java#L174 Just that the name-matching has to be exact (only ignoring case).

Probably the existing tools.

Post your project as a git repository, because that's the easiest way for me to look at everything.

I don't know what you're current problem with them is

No datafixers exist for mods. You removed it and the game is complaining that it was removed when loading a world that was created before the removal. You expected something else?

...huh, I didn't know that lang files were json now. I missed that change.

That would do it, thanks. I've been looking for that for...well, years.

No, those are overridden. There's no way to "merge" things like recipes and advancements. Tags are just lists of items. (Forge added a few extra bits of functionality, such as a way to list things to remove from a tag without overwriting entirely).

...you realize that one of the parameters of the tag json definition is called "replace" and if you say "false" they add together, right? https://minecraft.gamepedia.com/Tag#JSON_format Example being used: https://github.com/Draco18s/ReasonableRealism/blob/1.14.4/src/main/resources/data/minecraft/tags/blocks/rails.json

I have literally been unable to find this setting every time I've looked for it. Even just now.

Does it output the correct number?

By the way, the forum doesn't support signatures well. They are not displayed under your posts. And if you did change your "about me" it is not visible on your profile. Just post the link in this thread.

This is wrong. It should be: part.name=Text: %s %s %s

You need to specify that in the Container as a different subclass of Slot. Completely and utterly unrelated to any of your code. All that error is is the player account being used in dev can't be authenticated with Mojang's servers (i.e. the "account" doesn't exist). This is a non-issue. That sounds like nothing is happening on the server and everything you're seeing is on the client. But you haven't posted any code, so who knows.

A) I doubt that B) define "works"

HMM.

So, in other words, you changed nothing and it is a surprise that it doesn't work.

So, yes, that is what you meant. Because the method in BlockState is called with(...)(or withProperty(...)) depending on exactly which MC version you're on), but that gives you literally zero useful information because it takes two generic parameters, and if you want what those parameters are then I'm answering the question I thought you were asking, not the question you actually clarified as to be asking.

Do you mean: "How do I get the current block state, alter it, and put the changes back?"

This is wrong. Check the documentation again.

I do not understand what this means. By changing the block state of the snow layer block.

player.getHeldItem(hand)?

Pretty much. There's comments on a lot of methods that tell you what they're for and most parameters can be inferred based on their Type. See prior comment. Mostly either by trial and error or by having done dimension work on a prior version and already knowing some of the things that were required. Biomes work pretty much just like blocks and items. You just won't see them "spawn" naturally because they haven't been added to the BiomeController* (which is the code that handles worldgen). *BiomeProvider, I can't remember what it's currently called. There's one for each dimension (and one for flat worlds).

So, just a few things (but not related to your issue, just code style problems): This is copy-pasted decompiled code. There's no reason to use Boolean.valueOf There's no reason for a cast here. You are passed a hand in this function, you should query based on the hand given to you. If the purpose of this code is to continuously set the block above to be fire, there's a better way to do this. Make your block infinitely burnable (like netherack) and set the fire once in onBlockActivated. Then you don't need the tick method or the LIT property at all.

Well, I already pointed out what I think is wrong with it.