This library attempts to decouple Spottedleafs DataConverter from Minecraft in order to allow non-vanilla services to read and update legacy worlds. Many of the fixes and data conversions have been completely untested and the library may break at any time
CafeStube utilizes this to upgrade replay files from older versions of Minecraft to the latest version.
When you use this library, you completely accept the risk that dataconverters WILL NOT RUN CORRECTLY on your data. Your data data WILL BECOME CORRUPT as a result, and it is entirely YOUR FAULT.
DFU uses Schema's to define data layouts for types. They don't define all fields in the type, just the parts that need to be looked at for conversion. For example, here is the schema specification for Enderman (V100, 15w32a):
schema.register(map, "Enderman", (string) -> {
return DSL.optionalFields("carried", References.BLOCK_NAME.in(schema), equipment(schema));
});This specifies that the root CompoundTag for Enderman contains a BLOCK_NAME at path "carried."
It should be obvious that Schemas tell DFU's type system where to look if a datafixer wants to convert
BLOCK_NAME in this case.
More complicated schemas exist, for example (V100 again):
schema.registerType(false, References.STRUCTURE, () -> {
return DSL.optionalFields(
"entities", DSL.list(
DSL.optionalFields("nbt", References.ENTITY_TREE.in(schema))
),
"blocks", DSL.list(
DSL.optionalFields("nbt", References.BLOCK_ENTITY.in(schema))
),
"palette", DSL.list(References.BLOCK_STATE.in(schema))
);
});This schema specifies that the root tag of STRUCTURE contains 3 paths: entities, blocks, and palette.
In the entities path, it specifies that it's a List and that the list contains fields, so it is typically
a CompoundTag. This CompoundTag contains a field called "nbt", and the value represents an ENTITY_TREE.
The blocks path is similar to the entities path, except its "nbt" field represents a BLOCK_ENTITY, not
an ENTITY_TREE.
Finally, the palette field represents a list of BLOCK_STATE.
This aspect of DFU is the cleanest, and allows Mojang to define types easily and reliably - datafixers just need to define what type they want to modify, and the type system of DFU will navigate to the types and run them through the datafixer.
Like the DFU Schema, the DataWalker is designed to specify the data layout of types for dataconverters. However, the DataWalker's responsibly isn't to lay out the data - it's to actually run the converters. For example, take the schemas above, here are the DataWalker implementations:
MCTypeRegistry.ENTITY.addWalker(VERSION, "Enderman", (data, fromVersion, toVersion) -> {
WalkerUtils.convert(MCTypeRegistry.BLOCK_NAME, data, "carried", fromVersion, toVersion);
// only return something if we want the root tag to change, but we don't - so ret null. Don't worry about this,
// no DataWalker is actually recommended to do this.
return null;
});As you can see, the DataWalker is simply a piece of code that calls converters.
For the more complicated Schema:
MCTypeRegistry.STRUCTURE.addStructureWalker(VERSION, (data, fromVersion, toVersion) -> {
final ListType entities = data.getList("entities", ObjectType.MAP);
if (entities != null) {
for (int i = 0, len = entities.size(); i < len; ++i) {
WalkerUtils.convert(MCTypeRegistry.ENTITY, entities.getMap(i), "nbt", fromVersion, toVersion);
}
}
final ListType blocks = data.getList("blocks", ObjectType.MAP);
if (blocks != null) {
for (int i = 0, len = blocks.size(); i < len; ++i) {
WalkerUtils.convert(MCTypeRegistry.TILE_ENTITY, blocks.getMap(i), "nbt", fromVersion, toVersion);
}
}
WalkerUtils.convertList(MCTypeRegistry.BLOCK_STATE, data, "palette", fromVersion, toVersion);
// only return something if we want the root tag to change, but we don't - so ret null. Don't worry about this,
// no DataWalker is actually recommended to do this.
return null;
});There are no helper functions for converting a single field inside a list, so the list must be iterated over
manually. However, as you can see for the palette converter, there is a helper function for converting
lists of just one data type.
While DFU Schema and DataWalker are fundamentally different ways of performing data conversion for subtypes, they will both effectively end up doing the same thing. They are both designed to simply run converters on types contained within another type. However, DataWalker is much faster because it does not depend on an extremely large type system backend to the traversing for it - it does the traversing itself. Without the DFU type system, the vast majority of performance overhead and complexity has been eliminated already.
DataFix is the overall class responsible for making modifications to data. This is where the actual conversion process takes place. Because the DataFix classes can get extremely complicated, I'm only going to show a simple DataFix class (for V109, 15w33a):
public class EntityHealthFix extends DataFix {
private static final Set<String> ENTITIES = ...; // unused set of entities with Health
public EntityHealthFix(Schema schema, boolean changesType) {
// schema specifies the version
super(schema, changesType);
}
public Dynamic<?> fixTag(Dynamic<?> entityRoot) {
// while the variable names say float and int, really the type is `Number` - it can be
// any Number. But I've named them according to what we _expect_ them to be, as that's
// very important to the datafix here.
Optional<Number> healthFloat = entityRoot.get("HealF").asNumber().result();
Optional<Number> healthInt = entityRoot.get("Health").asNumber().result();
float newHealth;
if (healthFloat.isPresent()) {
newHealth = ((Number)healthFloat.get()).floatValue();
entityRoot = entityRoot.remove("HealF");
} else {
if (!healthInt.isPresent()) {
return entityRoot;
}
newHealth = ((Number)healthInt.get()).floatValue();
}
return entityRoot.set("Health", entityRoot.createFloat(newHealth));
}
public TypeRewriteRule makeRule() {
return this.fixTypeEverywhereTyped("EntityHealthFix", this.getInputSchema().getType(References.ENTITY), (typed) -> {
return typed.update(DSL.remainderFinder(), this::fixTag);
});
}
}The converter is fairly straightforward - update the Health tag to be a float. If HealF exists, then use
that - else, try to use the Health tag. If none exist, do nothing.
The makeRule() method is there to tell DFU it wants to modify all ENTITY types.
Something you need to note is that Dynamics are Copy-On-Write (they do SHALLOW copies, not DEEP). This is why you will see lines like this:
entityRoot = entityRoot.remove("HealF");You will see in a moment that DataConverter is not Copy-On-Write. This is something very important that you need to keep in mind if you want to look at both DataConverter's converters and DFU's.
DataConverters are going to the same job of DataFix. Take an input data, do converting, and return an output data. Here's the converter for the health fix:
// version must be specified to the DataConverter
MCTypeRegistry.ENTITY.addStructureConverter(new DataConverter<>(VERSION) {
// versions are provided in the convert method. Not used much, but there just in case.
@Override
public MapType<String> convert(final MapType<String> data, final long sourceVersion, final long toVersion) {
final Number healF = data.getNumber("HealF");
final Number heal = data.getNumber("Health");
final float newHealth;
if (healF != null) {
data.remove("HealF");
newHealth = healF.floatValue();
} else {
if (heal == null) {
return null;
}
newHealth = heal.floatValue();
}
data.setFloat("Health", newHealth);
// null once again indicates we have no need to change the root tag. Rarely is this ever needed,
// but sometimes it is. See V135's passenger fix - it needs to change root tag because the Riding
// entities are swapped with passengers.
return null;
}
});You will notice that no Optionals have been used. Null is to indicate when values do not exist (or when the type is not as requested).
The code does basically the same thing. However, it uses MapType instead of Dynamic for reading and writing to
the underlying CompoundTag. Why not just write to CompoundTag directly? Technically I also need to support
read/write operations to JSON data (see ADVANCEMENTS type). So the MapType is an abstraction.
Performance impact is low since operations are not Copy-On-Write and do not go through a type system. DataConverters are simple enough that no optimising is really needed, because the performance problem of DFU simply doesn't exist: its type system. In fact, the only DataConverter I ever optimised was the chunk flatten converter (DataConverterFlattenChunk).
DataConverters tend to stay simple because there is no type system to deal with at all, so all the complexity comes from the logical data changes occurring. This makes debugging them easy. For example, take a look at the MinecartSpawner Schema/DataWalker (V99, pre-converters):
DataWalker:
// Yes, two walkers are allowed: but only for the same version. Later versions need to redefine
// them all, if they're needed.
MCTypeRegistry.ENTITY.addWalker(VERSION, "MinecartSpawner", new DataWalkerBlockNames("DisplayTile"));
MCTypeRegistry.ENTITY.addWalker(VERSION, "MinecartSpawner", MCTypeRegistry.UNTAGGED_SPAWNER::convert);Schema:
schema.register(map, "MinecartSpawner", () -> {
return DSL.optionalFields("DisplayTile", References.BLOCK_NAME.in(schema), References.UNTAGGED_SPAWNER.in(schema));
});They look the same right? Well they are. It turns out, the root tag of MinecartSpawner is also an UNTAGGED_SPAWNER.
While this is completely acceptable in DataConverter, because it's just going to run convert(), DFU chokes a bit.
Well what happens if you shove a MinecartSpawner through DFU?
This.
Complete mess
class_3602 -> EntityHorseSplitFix
class_1167 -> EntityTransformFix
Yup that's right, this stacktrace doesn't even point to any DataFix that even touches Minecarts or Spawners. It doesn't even point anywhere near one. So good luck figuring that one out from the stacktrace. I figured this out only by curious inspection, and only wanted to see if DFU could even handle it.
Imagine this happening to some data you actually care about though. You cannot debug it. I remember during 1.16 when Paper was trying to fix massive lag problems caused by errors in DFU. It took basically 5 or so people to cobble together a solution, and that solution was total trash. No offense to anyone involved (I was involved), but that's just the best we could've done with DFU. An issue occurs, and you just have to pray that one of the few people who understand this system can do something about it.
java.lang.IllegalArgumentException: Couldn't upcast
at com.mojang.datafixers.TypedOptic.lambda$apply$0(TypedOptic.java:60) ~[datafixerupper-4.0.26.jar:?]
at java.util.Optional.orElseThrow(Optional.java:403) ~[?:?]
at com.mojang.datafixers.TypedOptic.apply(TypedOptic.java:59) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.Typed.get(Typed.java:48) ~[datafixerupper-4.0.26.jar:?]
at net.minecraft.class_3602.method_4982(class_3602.java:19) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_1167.method_4984(class_1167.java:30) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$first$1(FunctionType.java:81) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Fold.lambda$null$2(Fold.java:48) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$first$1(FunctionType.java:81) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$first$1(FunctionType.java:81) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Fold.lambda$null$2(Fold.java:48) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$null$3(FunctionType.java:93) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.optics.ListTraversal.lambda$wander$0(ListTraversal.java:19) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$wander$4(FunctionType.java:94) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.lambda$mapRight$1(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Right.map(Either.java:99) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either.mapRight(Either.java:166) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$right$6(FunctionType.java:104) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$first$1(FunctionType.java:81) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$first$1(FunctionType.java:81) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.FunctionType$Instance.lambda$first$1(FunctionType.java:81) ~[datafixerupper-4.0.26.jar:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at java.util.function.Function.lambda$compose$0(Function.java:68) ~[?:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.functions.Comp.lambda$null$5(Comp.java:69) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.types.Type.capWrite(Type.java:167) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.types.Type.lambda$readAndWrite$9(Type.java:159) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.serialization.DataResult.lambda$flatMap$10(DataResult.java:138) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.util.Either$Left.map(Either.java:38) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.serialization.DataResult.flatMap(DataResult.java:136) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.types.Type.readAndWrite(Type.java:158) ~[datafixerupper-4.0.26.jar:?]
at com.mojang.datafixers.DataFixerUpper.update(DataFixerUpper.java:84) ~[datafixerupper-4.0.26.jar:?]
at net.minecraft.class_2512.method_10693(class_2512.java:466) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_3977.method_17907(class_3977.java:37) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_3898.method_17979(class_3898.java:863) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_3898.method_17256(class_3898.java:520) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1764) ~[?:?]
at net.minecraft.class_1255.method_18859(class_1255.java:144) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_3215$class_4212.method_18859(class_3215.java:545) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_1255.method_16075(class_1255.java:118) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_3215$class_4212.method_16075(class_3215.java:554) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_3215.method_19492(class_3215.java:280) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_20415(MinecraftServer.java:749) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_16075(MinecraftServer.java:737) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_1255.method_18857(class_1255.java:127) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_16208(MinecraftServer.java:722) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_3774(MinecraftServer.java:505) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_3735(MinecraftServer.java:338) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.class_1132.method_3823(class_1132.java:67) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:645) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:257) ~[intermediary-fabric-loader-0.11.3-1.16.5.jar:?]
at java.lang.Thread.run(Thread.java:831) [?:?]
TL;DR big stacktrace gives only misleading information.
This concludes the general technical overview. If you want to contribute, you should first
take a look at a variety of DataFix's I have ported over. There you can see how I handled
complicated DataFix's and very basic ones (like simple item/block/entity renames) and how I
expect converters to be laid out. You can start at MCTypeRegistry - this is where all converters
and walkers are registered.
- Minecart Spawner's do not fail to convert for pre converter data.
- Flower pot items convert correctly (there were several problems...)
- Fix logs like
Unable to resolve BlockEntity for ItemStack- Mojang did not specify the full Item name -> Block Entity map. I have code that will ensure the map includes everything. - Fix incorrect potion conversion from ancient versions (pre converters). Not sure why DFU breaks here...
- Tamed wolf collar colours are not managled during the Flattening conversion
- Incorrect handling of modern entity items that have entity NBT contained within them (spawn eggs, item frames)
This data converter is new. Of course there are going to be bugs. Please take backups before using, and if you find problems you need to open a report with the relevant logs and world data. And then they will actually get fixed, because this system is actually debuggable.
As time goes on, this converter will become more reliable than DFU since this converter is more easily debugged. So fixing things is actually practically possible.
The new data converter is at minimum 30 times faster than DFU for converting freshly generated 1.7.10 worlds to 1.17 (this runs through all data converters, so it's a solid test). When chunks contain a lot of data (like shulkers with lots of items), the converter can be up to 200 times faster.
This is fast enough in my testing to completely obsolete the usage of Force Upgrading. I tested force upgrading this world: Realm of Midgard v30
My SSD is a Samsung 970 EVO 1TB (NVMe). So the Disk I/O should be minimized. Conversion process broke down like this:
- ~75% was spent on reading/writing the chunk data (this INCLUDES decompression/compression)
- ~25% was spent converting the data
So basically, the vast majority of time is spent on read/write. Why bother force upgrading? Literally a waste of your time with DataConverter.
New converter system makes force upgrading obsolete, that's how fast it is. New converter system is new, so please do backups before using - or else you put your world data at risk.