LegacyCraft-Core

A Forge CoreMod for Minecraft 1.12.2 that silently fixes runtime crashes and missing connections caused by API mismatches between the mods in the LegacyCraft modpack.

All patches are applied transparently at class-load time using ASM bytecode transformation. No config needed, no gameplay changes — it simply makes incompatible mods work together.

What It Fixes

AkutoEngine + BuildCraft Remastered

flyingperson23's BuildCraft Remastered changed two internal APIs after AkutoEngine 2.0.13 was released. Without this CoreMod, the game crashes immediately on startup with NoSuchMethodError.

Gate recipe crash on startup

AkutoEngine calls new GateVariant(logic, material, modifier) with 3 arguments, but BuildCraft Remastered dropped the EnumGateModifier parameter from the constructor. LC-Core rewrites the call site in ObjHandler.registerRecipes() to discard the unused modifier and invoke the correct 2-argument constructor instead.

Engine MJ power crash

AkutoEngine calls getReceiverToPower(TileEntity, EnumFacing) with 2 arguments, but BuildCraft Remastered removed the TileEntity parameter. LC-Core rewrites every call site in TileEntityAkutoEngineBase to drop the TileEntity from the stack and invoke the correct 1-argument version — allowing engines to push MJ power normally.

Logistics Pipes 0.10.4.28+ + BuildCraft Remastered / IC2 Classic

LP 0.10.4.28 quietly removed three pipe-connection checks that existed in 0.10.4.27. As a result, pipes with power-related upgrades installed lose the ability to connect to adjacent machines entirely.

RF Power Supplier Upgrade does not connect to BC Laser or Forge Energy machines

LP 0.10.4.28+ removed the Forge Energy receiver check from canPipeConnect_internal(), so a Logistics Pipe with the RF Power Supplier Upgrade installed never forms a physical connection to BuildCraft Lasers or any IEnergyStorage-capable block.

LC-Core restores this check using tile.hasCapability(CapabilityEnergy.ENERGY, facing). Crucially, it checks for capability presence rather than battery state, so the pipe stub is always shown on Forge Energy blocks regardless of whether the battery is currently full. Actual power delivery is still gated by LP's own logic (requestRFPower() → isEnergyReceiver()), so no power is wasted to already-full batteries.

IC2 EU Power Supplier Upgrade does not connect to IC2 machines

The same LP 0.10.4.28 change also removed the IC2 energy-sink check. LC-Core restores IC2Proxy.isEnergySink() connectivity, guarded by the pipe's getIC2PowerLevel() > 0 condition, so EU power upgrades reconnect to IC2 Classic machines.

EnderIO conduit connection (LP 0.10.4.27 – 0.10.4.48)

LP 0.10.4.28 removed the enderIOProxy.isItemConduit() check. LP 0.10.4.49 went further and deleted the SimpleServiceLocator.enderIOProxy field entirely. LC-Core detects at transform time whether the field is present and emits the EnderIO conduit check only when it exists — no crashes across LP versions.

Additional Robustness

Automatic MCP/SRG method name detection

In production Minecraft jars, EnumFacing.getOpposite() is obfuscated to func_176734_d. In development environments (after rfg.deobf()), it appears as getOpposite. LC-Core scans the Logistics Pipes bytecode at transform time to detect which name is in use and emits the matching call automatically — no environment-specific configuration required.

About LegacyCraft

LegacyCraft is a lightweight Minecraft 1.12.2 modpack that recreates the atmosphere of early tech-mod gameplay (circa 1.2.5 era) with BuildCraft, Logistics Pipes, IC2 Classic, ProjectE, and Project Red. LC-Core is the glue that makes those mods coexist without crashes.

LegacyCraft Core