How do you deal with block / item ID changes?

[Insane96MCP]

I'm in need of changing the id of an item but this would break the compatibility of current worlds. How should I deal with this?

[V0idWa1k3r]

I think you can use the RegistryEvent.MissingMappings event to deal with this. From that event you can get the list of mappings. Get the one that was changed and use Mapping#remap to point to the thing with the new name.

[Insane96MCP]

16 hours ago, V0idWa1k3r said:

I think you can use the RegistryEvent.MissingMappings event to deal with this. From that event you can get the list of mappings. Get the one that was changed and use Mapping#remap to point to the thing with the new name.

Thanks this worked out thanks to numerical IDs, but the question now is, afaik in 1.13 they removed numerical IDs so how will remapping work?

[Draco18s]

It'll operate on strings, obviously. "Oh no can't find modid:someblock".

[Insane96MCP]

On 10/7/2018 at 4:27 PM, Draco18s said:

It'll operate on strings, obviously. "Oh no can't find modid:someblock".

Ok, but right now remapping seems to use numerical ids, since there will be no more, and string ids get changed, when you need remapping, how can this work?

[Animefan8888]

4 hours ago, Insane96MCP said:

Ok, but right now remapping seems to use numerical ids, since there will be no more, and string ids get changed, when you need remapping, how can this work?

Numerical ids won't ever go away, they are and still will be used for serialization(as far as I know).

[V0idWa1k3r]

5 minutes ago, Animefan8888 said:

they are and still will be used for serialization(as far as I know).

As I understand the new system only chunks will use numerical IDs to resolve a blockstate at a given location. So while they are not going away and are still used for serialization you have no control over them and the mappings won't hold them since each chunk has it's own set of IDs <-> Name pairs.

 

4 hours ago, Insane96MCP said:

when you need remapping, how can this work?

You will simply tell the game in this event that "Oh, X actually equals Y". Kinda like telling the game that modid:some_name is just a pointer to modid:some_other_name. So when the game asks for modid:some_name it will just be resolved to modid:some_other_name. Think of it as making a symlink.

[Animefan8888]

1 hour ago, V0idWa1k3r said:

since each chunk has it's own set of IDs <-> Name pairs. 

This just sounds horrible to me.

1 hour ago, V0idWa1k3r said:

and the mappings won't hold

I'm not sure if that is correct, I also don't know if I am understanding it. But just in case.

Quote

A word about integer ID's

• For Items and Blocks, you should have already switched to fully using registry names for everything. The registry name <-> int ID maps still exist in vanilla for performance purposes, but they should never be used for anything other than network communication because they are NOT guaranteed to be the same after joining a different world. This should already be an established modding convention since 1.8, but people still break it, so I'll mention it again

From the update primer.

[V0idWa1k3r]

59 minutes ago, Animefan8888 said:

I'm not sure if that is correct, I also don't know if I am understanding it. But just in case.

https://minecraft.gamepedia.com/Talk:Chunk_format

[Draco18s]

19 hours ago, Insane96MCP said:

Ok, but right now remapping seems to use numerical ids, since there will be no more, and string ids get changed, when you need remapping, how can this work?

The event's fields would change, duh.

[TheRPGAdventurer]

Hey guys I tried to make my own, but it failed, Where did I make my mistake

    @SubscribeEvent
    public void missingMapping(RegistryEvent.MissingMappings<Item> event) {
        for (MissingMappings.Mapping<Item> entry : event.getAllMappings()) {
            if (entry.key.toString().equals(DragonMounts.MODID + ":ender_dragonscales"))  {
                ResourceLocation newTotem = new ResourceLocation(DragonMounts.MODID + ":ender_dragonscales1");
                entry.remap(ForgeRegistries.ITEMS.getValue(newTotem));
            }
        }
    }