I'm porting a 1.18.2 mod of mine to 1.19.2, and my tree decorator isn't working correctly. 

I have a custom tree that is supposed to generate with my custom decorator, but when I try to open a world I get the 'load in safe mode' screen. When I replace the AvocadoBundleTreeDecorator with CocoaDecorator it works, so the decorator is definitely the problem.

public static final Holder<ConfiguredFeature<TreeConfiguration, ?>> AVOCADO_TREE =
            FeatureUtils.register("avocado", Feature.TREE, new TreeConfiguration.TreeConfigurationBuilder(
                    BlockStateProvider.simple(ModBlocks.AVOCADO_LOG.get()),
                    new StraightTrunkPlacer(3, 2, 0),
                    BlockStateProvider.simple(ModBlocks.AVOCADO_LEAVES.get()),
                    new AcaciaFoliagePlacer(ConstantInt.of(3), ConstantInt.of(0)),
                    new TwoLayersFeatureSize(1, 0, 1))
                    .decorators(ImmutableList.of(new AvocadoBundleTreeDecorator(1))).ignoreVines().build());

I'm not sure what the issue is, as AvocadoBundleTreeDecorator is set out almost identically to the 1.19.2 CocoaDecorator, and it functioned fine in the 1.18.2 version.

public class AvocadoBundleTreeDecorator extends TreeDecorator {
    public static final Codec<AvocadoBundleTreeDecorator> CODEC = Codec.floatRange(0.0F, 1.0F).fieldOf("probability").xmap(AvocadoBundleTreeDecorator::new, (p_69989_) -> {
        return p_69989_.probability;
    }).codec();
    private final float probability;

    public AvocadoBundleTreeDecorator(float p_69976_) {
        this.probability = p_69976_;
    }

    protected TreeDecoratorType<?> type() { return TreeDecoratorType.LEAVE_VINE; }

    public void place(TreeDecorator.Context p_226028_) {
        RandomSource randomsource = p_226028_.random();
        if (!(randomsource.nextFloat() >= this.probability)) {
            List<BlockPos> list = p_226028_.logs();
            int i = list.get(0).getY();
            list.stream().filter((p_69980_) -> {
                return p_69980_.getY() - i <= 2;
            }).forEach((p_226026_) -> {
                for(Direction direction : Direction.Plane.HORIZONTAL) {
                    if (randomsource.nextFloat() <= 0.25F) {
                        Direction direction1 = direction.getOpposite();
                        BlockPos blockpos = p_226026_.offset(direction1.getStepX(), 0, direction1.getStepZ());
                        if (p_226028_.isAir(blockpos)) {
                            p_226028_.setBlock(blockpos, ModBlocks.AVOCADO_BUNDLE.get().defaultBlockState());
                        }
                    }
                }
            });
        }
    }
}

Here is the Github page if needed.

Props for showing all the code, so I can see what your problem is.

But you could have saved some time if you just posted the error instead making me build and run your project to see it.

Quote

Caused by: java.lang.ClassCastException: class com.ncpbails.culturaldelights.world.feature.tree.treedecorator.AvocadoBundleTreeDecorator cannot be cast to class net.minecraft.world.level.levelgen.feature.treedecorators.LeaveVineDecorator (com.ncpbails.culturaldelights.world.feature.tree.treedecorator.AvocadoBundleTreeDecorator is in module [email protected] of loader 'TRANSFORMER' @6f70a21b; net.minecraft.world.level.levelgen.feature.treedecorators.LeaveVineDecorator is in module [email protected] of loader 'TRANSFORMER' @6f70a21b)
        at com.mojang.serialization.MapEncoder$1.encode(MapEncoder.java:26) ~[datafixerupper-5.0.28.jar%23147!/:?] {}
 

You have;

Quote

protected TreeDecoratorType<?> type() { return TreeDecoratorType.LEAVE_VINE; }

 

Which uses a LeaveVineDecorator according to its CODEC.

You need to create and register your own TreeDecoratorType that uses your codec so it knows how to (de)serialize your decorator to and from json

The relevant registry is 

https://github.com/MinecraftForge/MinecraftForge/blob/b5073c10efb3154720a8039b2d7e131fd9fabe24/src/main/java/net/minecraftforge/registries/ForgeRegistries.java#L95

 

By the way, modifying the builtin registries to create Configured/PlacedFeatures hasn't been the correct way to do it since 1.18.1 (if it was even correct then)

and won't work at all with Mojang's new way of doing things in 1.19.3