Proposal: native registry API

[drtheodor]

The why

Instead of doing custom registries like modkit does right now, we could use MC's built-in registry system. This would give us a lot of benefits like stability and speed, as well as native support for all the registry shenanigans.

The how

Obviously, this means that the registry elements will lose GSON support, opting for Codecs instead.

First, we need to inject into RegistryLoader#DYNAMIC_REGISTRIES list field. Registry's element's codecs can be whatever, but referencing registry elements in other registry element codecs is better to do via RegistryElementCodec, as seen in DimensionType and DimensionOptions.

[duzos]

i like it but have no clue on how to do it
if you could make a branch mayhaps..

[drtheodor]

TODO:

• Custom RegistryLoader.Entry's getLoader implementations for default and custom ids
• A more convenient Identifier constructor for the registry builder

[duzos]

this is the right direction and it kills #26 for free — vanilla rebuilds the whole DynamicRegistryManager per world load + resyncs on join, so there's no long-lived map to leak. SimpleDatapackRegistry already requires a Codec<T> so the codecs mostly carry over; the gson deserializer just becomes redundant.

rough plan:

1. define a RegistryKey<Registry<T>> per existing datapack registry (keep the same data path so existing json still works)
2. inject (key, codec) into RegistryLoader.DYNAMIC_REGISTRIES via mixin
3. replace our get/getRandom/toList/iterator with thin wrappers over the native Registry from RegistryAccess
4. convert cross-refs to RegistryElementCodec/RegistryEntry
5. delete our custom sync packets — vanilla syncs dynamic registries automatically

caveat: it's an api break for every downstream (AIT exteriors/sonics, addons), the DYNAMIC_REGISTRIES injection is version-sensitive, and builtin/default entries have to become data or a RegistrySetBuilder. do it as a major version bump and phase one registry type first behind the existing interface before ripping out the gson path.