misode.github.io/guides/feature-order-cycle.md

title, versions, tags

title	versions	tags
How to fix feature order cycles	1.18 1.18.2 1.19	worldgen biomes features

java.lang.IllegalStateException: Feature order cycle found, involved biomes

Are you getting this frustrating error? Let's look at why it happens and how to prevent it.

Why does it happen?

Feature order cycles happen when two biomes reference the same placed feature in the same step, but in a different order.

Let's try with an example. We have two biomes here:
data/example/worldgen/biome/forest.json

{
  ...
  "features": [
    [],
    [
      "example:blue_tree",
      "example:red_tree",
      "example:rocks",
    ]
  ]
}

data/example/worldgen/biome/plains.json

{
  ...
  "features": [
    [
      "example:blue_tree"
    ],
    [
      "example:rocks",
      "example:blue_tree"
    ]
  ]
}

When we try to load these biomes, data pack validation will fail because in the example:forest biome in step 2, sblue_tree is before srocks; while in the example:plains biome, srocks is before sblue_tree.

How to fix it

The rule is that for each step in f"features", all feature IDs need to be ordered consistently across biomes.

The above example can be fixed by swapping the features in step 2 of the plains biome:
data/example/worldgen/biome/plains.json

{
  ...
  "features": [
    [
      "example:blue_tree"
    ],
    [
      "example:blue_tree",
      "example:rocks"
    ]
  ]
}

If your data pack is more complicated, with multiple biomes and lots of features, this will be a harder process. Since 1.18.2, the error will include the conflicting biome IDs.

If you want more detailed errors, a useful mod is Cyanide. This will show the exact feature cycle that's causing problems, as well as other worldgen related errors.