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Chain Flattening

When you define multiple remaps that form a chain (A→B and B→C), RemapIDs automatically resolves them into a direct mapping (A→C). This simplifies configuration and avoids unnecessary intermediate lookups.

How Chains Work​

If your config files contain:

{
  "remaps": [
    { "source": "modA:silver_ingot", "target": "modB:silver_ingot" },
    { "source": "modB:silver_ingot", "target": "thermal:silver_ingot" }
  ]
}

RemapIDs flattens these into:

  • modA:silver_ingot → thermal:silver_ingot
  • modB:silver_ingot → thermal:silver_ingot

The intermediate mapping is resolved automatically. Both original source IDs end up pointing to the final target.

Chain Depth Limit​

Chains are resolved up to a maximum depth of 10. If a chain exceeds this limit, it is treated as likely circular and rejected with an error in the log.

For most real-world use cases, chains are only 2-3 levels deep. If you hit the depth limit, check for accidental cycles.

Circular Detection​

RemapIDs detects and rejects circular mappings. If your config contains:

{
  "remaps": [
    { "source": "modA:silver_ingot", "target": "modB:silver_ingot" },
    { "source": "modB:silver_ingot", "target": "modA:silver_ingot" }
  ]
}

Both mappings are rejected and an error is logged. Self-remaps (a source that maps to itself) are silently dropped.

When Chains Are Useful​

Migrating through multiple mod replacements​

If your modpack previously replaced Mod A with Mod B, and now you're replacing Mod B with Mod C, you can keep the old A→B remap and simply add B→C. Players with items from any generation will resolve to the current mod:

File: 01-old-migration.json

{
  "remaps": [
    { "source": "modA:silver_ingot", "target": "modB:silver_ingot", "types": ["item"] }
  ]
}

File: 02-new-migration.json

{
  "remaps": [
    { "source": "modB:silver_ingot", "target": "thermal:silver_ingot", "types": ["item"] }
  ]
}

RemapIDs flattens these across files — the alphabetical processing order ensures both files are loaded before chain resolution runs.

Organizing remaps across files​

Because chain flattening works across multiple config files, you can keep remaps organized by mod or migration phase without worrying about dependencies between files.

warning

Chains exceeding 10 levels are treated as likely circular and are rejected. If you need very deep migrations, consider collapsing intermediate steps into direct mappings.

Next Steps​