Fabricated Legacy Forge

A compatibility layer that lets legacy Minecraft Forge/FML mods run on Fabric Loader for Minecraft 1.3.2.

Available on Modrinth: https://modrinth.com/mod/fabricated-forge

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What it does

Forge mods written for Minecraft 1.3.2 expect the old Forge/FML (Forge Mod Loader) APIs and use obfuscated class names. Fabric Loader uses a completely different mod-loading pipeline and the Calamus namespace. This project bridges the two:

• Bootstraps the FML mod-loading lifecycle (mod discovery, @Mod initialization, event bus, coremods) inside a Fabric preLaunch entrypoint
• Remaps class/method/field references at runtime so mods compiled against Searge/MCP names resolve correctly against the Fabric-deobfuscated game
• Intercepts reflection calls (Class.forName, getDeclaredMethod, etc.) at the bytecode level so runtime lookups are also remapped
• Reimplements the MinecraftForge API surface (block hooks, entity events, rendering extensions, IBXM audio) as Fabric Mixins

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Requirements

Dependency	Version
Minecraft	1.3.2
Fabric Loader	≥ 0.18.2
Mod Remapping API	≥ 1.28.3

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Project structure

fabricated-fml/          Core FML implementation
  src/main/java/         Mixins + mod-loading code
  src/main/resources/    fabricated-fml.mixins.json, access widener
  patches/               Legacy source patches (do not add new ones here)

fabricated-forge/        MinecraftForge API layer
  src/main/java/         Mixins + Forge hooks
  src/main/resources/    fabricated-forge.mixins.json, access widener
  patches/               Legacy source patches (do not add new ones here)

fabricated-forge-server-stubs/   Server-side versions of classes originally only available on the client
flf-mod-fixes/                   Runtime fixes for known problematic Forge mods

New Minecraft class modifications should be Mixins, not patches. The patches/ directories are legacy and are being migrated.

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Building

Requires JDK 17 (produces Java 8 bytecode).

# Build everything
./gradlew build

# Apply code style (required before committing)
./gradlew spotlessApply

# Build a single submodule
./gradlew :fabricated-fml:build
./gradlew :fabricated-forge:build

CI validates with spotlessCheck + build. There are no automated tests.

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Contributing

• All Minecraft class modifications must use Spongepowered Mixins, not patches.
• Use access wideners to expose private members; avoid reflection inside project code.
• Run ./gradlew spotlessApply before committing — CI enforces the style check.
• OptiFine compatibility is handled in FabricatedFMLMixinPlugin; keep that in mind when adding Mixins that touch rendering.

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License

This project bundles code from several upstream projects under different licenses. See licensing.md for the full breakdown.

Component	License
Project code (io.github.fabriccompatibilitylayers.*)	OSL-3.0
Forge Mod Loader (cpw.mods.fml.*)	LGPL-2.1
MinecraftForge (net.minecraftforge.*)	Minecraft Forge Public License v1.0
IBXM (ibxm.*)	BSD-3-Clause
Paulscode SoundSystem CodecIBXM	Paulscode-SoundSystem (custom permissive)