NeoForge 1.21.1 Port

[theShroo]

Summary

Full port of NuclearCraft Neoteric from Forge 1.20 to NeoForge 21.1.219 / Minecraft 1.21.1 / Java 21.

Note: This PR targets 1.20 because there is no 1.21 branch yet. Please consider creating a 1.21 branch and retargeting this PR before merging.

Migration completed:

• Build system — Gradle 8.10, NeoGradle, NeoForge 21.1.219
• Package renames — net.minecraftforge → net.neoforged.neoforge
• Registration system — DeferredRegister / DeferredHolder with typed factory methods
• Capability system — RegisterCapabilitiesEvent + IItemHandler/IFluidHandler/IEnergyStorage
• Networking — CustomPacketPayload records via RegisterPayloadHandlersEvent
• ItemStack data — DataComponents.CUSTOM_DATA via NCItemStacks / NCFluidStacks platform layer
• Blocks/Items/Fluids — LiquidBlock(FlowingFluid), burn time semantics, ArmorMaterial registry
• Recipes — RecipeHolder unwrapping, MapCodec/StreamCodec, RecipeInput
• Client-side — RegisterColorHandlersEvent, RegisterClientExtensionsEvent, normalized UV coords
• Compat modules — JEI (NeoForgeTypes), Mekanism (unified Chemical), AE2 (19.2.17), EMI, GregTech, KubeJS (2101.7.2)
• Data generation — Tag renames (c: namespace), RecipeOutput, holder-based loot/enchantment APIs
• Mixins — All active, including ParticleStackKubeJSMixin (KubeJS particle binding)
• World gen — Ore generation, biome modifiers, wasteland biome
• Entities — Wasteland boss, feral ghoul, projectiles, renderers
• Platform abstraction — igentuman.api.platform package with 15+ wrapper classes

KubeJS integration (new):

NC's internal KubeJS plugin has been fully ported to the KubeJS 2101.x API. KubeJS 1.21.1 exists and is actively maintained; the plugin was re-enabled and rewritten from the ground up against the new API surface.

What works:

• Recipe schema registration — Five per-recipe-type schemas covering all NC recipe types (generic processors, fission_boiling/turbine with heatRequired, fusion_coolant/accelerator_coolant with coolingRate, fusion_core with temperature, and target_chamber with particle components)
• Reading NC recipes from JS — event.forEachRecipe({mod: "nuclearcraft"}, ...) iterates all NC recipes with full field access via the Gson JSON API
• Creating NC recipes from JS — event.custom({type: "nuclearcraft:manufactory", input: [...], output: [...]}) creates new NC recipes that the NC runtime loader accepts
• Cross-mod recipe mirroring — Verified with manufactory↔Mekanism crusher mirror (315 recipes) and alloy smelter mirror across NC/Extended Industrialization/EnderIO/Oritech foundry (344 recipes), zero failures
• Custom fission fuel registration — NCKJSEvents.registerFissionFuel startup event for script-defined fuels with automatic recipe generation
• Black hole player event — NCKJSEvents.playerEnterBlackhole server event for script-controlled responses
• Particle recipe components — Custom RecipeComponent records for InputParticle/OutputParticle with full 4-field codecs (particle/amount/meanEnergy/focus) for target chamber round-trip fidelity
• Plugin discovery — kubejs.plugins.txt gates class loading on KubeJS mod presence; NC runs without KubeJS with zero overhead

What was removed:

• NCRecipeJS.java — Dead workaround that collapsed fluid tags to concrete fluids (lost tag fidelity). NeoForge's native FluidIngredient handles tags correctly now.
• KubeJSRecipesEventJSMixin.java — Target class RecipesEventJS no longer exists in KubeJS 2101.x. Diagnostic-only mixin that never worked per its own source comment.

Phase 16 fixes (multiblock formation + testing):

• Multiblock formation — Fix mutable BlockPosInstance corrupting dimension probes; use immutable BlockPos snapshots for all resolution methods
• Multiblock validation — Remove pre-reset of outerValid/innerValid/isFormed before validation; validate() sets state from actual results
• Client sync — Replace all 51 sendBlockUpdated calls with direct syncToTrackingClients() (sends ClientboundBlockEntityDataPacket directly, bypasses ChunkHolder dirty flag system)
• Port containers — Always add fuel slots with dummy handler fallback to prevent server/client slot count mismatch
• Port sync — Add sendBlockUpdated to all port setMultiblock() methods; remove early return before connected-state sync in FissionPortBE
• Cache invalidation — invalidateCache() only sets hasToRefresh flag, no longer resets controller BE fields
• Fluid tags — Migrate all fluid tags from neoforge: to c: namespace (1.21.1 convention); regenerate 9500+ datagen recipe JSONs
• Mekanism chemicals — Register CHEMICAL capability on all NC block entities; Chemical2FluidConverter maps chemicals to NC fluids via direct registry lookup
• Fluid tank colors — Use FluidEntry.color() directly in tank renderer (same fix as bucket colors)
• Push/pull slots — Fix early return in pushItems/pushFluids that skipped remaining output slots
• Tag-based fluid validation — isValidSlotFluid checks shared c: tags, not just exact fluid match
• Radiation packets — Snapshot HashMap on construction to prevent ConcurrentModificationException on Netty thread
• pack_format — Updated from 15 (1.20) to 34 (1.21.1)
• Block tag lookup — Use BlockState.is(TagKey) for NeoForge 1.21.1 tag resolution
• Datagen fix — NcRecipeBuilder now skips empty NcIngredient entries when serializing output arrays, fixing the non-standard output:[[]] shape that broke downstream consumers

Compat module status:

Module	Status
Mekanism	Migrated (Gas/Slurry → unified Chemical, CHEMICAL capability registered)
AE2	Re-enabled (19.2.17) with mod-loaded guards
JEI	Migrated (ForgeTypes → NeoForgeTypes)
EMI	Migrated (bumped 1.1.21 → 1.1.22 for KubeJS compat)
KubeJS	Migrated (2101.7.2 — full plugin rewrite, 5 recipe schemas, particle components, event bridges)
ComputerCraft	Migrated
GregTech	Migrated
The One Probe	Migrated
Patchouli	Migrated
OC2, TIS-3D, Refined Storage	Excluded (no 1.21.1 ports)

Testing done:

• Server + client launch clean (no NC errors)
• All 25+ processors tested — energy delivery, recipe processing working
• Fission reactor multiblock — forms correctly, UI syncs immediately, power production works
• Mekanism oxygen → NC fluid enricher — chemical conversion and recipe matching verified
• Isotope separator multi-output push to AE2 interface — all slots eject correctly
• Fluid tank colors render correctly in machine GUIs
• Battery blocks render correctly with side configuration
• Bucket fluid colors render correctly
• AE2 compat loads without errors
• EMI recipe categories display correctly
• Tested with SpeedChunk parallel ticking — no threading issues
• KubeJS plugin — Zero schema warnings across all NC recipe types on FTB Evolution modpack; 659 cross-mod recipes created via mirror scripts (0 failures)

Remaining work:

• Extended playtesting of other multiblocks (fusion, turbine, accelerator)
• Fusion reactor testing
• Production deployment

Test plan

• Install into FTB Evolution (1.21.1 NeoForge) for integration testing
• Test multiblock structures (fission reactor — forms and produces power)
• Test Mekanism chemical conversion recipes (oxygen verified)
• Test multi-output push to AE2 interfaces
• Test KubeJS plugin — recipe reading, creation, cross-mod mirroring
• Test fusion reactor multiblock
• Test turbine multiblock
• Verify world generation (ores, structures)
• Production deployment

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