How to Fix Errors in Worldgen Data Packs

Written by WafflesAreBetter

Introduction

This tutorial will cover the process of examining the Minecraft output log and identifying the specific text related to the error you are experiencing. It will then explain how to resolve issues with your world generation data pack based on the information found. Discovering what you need to find there, depending on your data generation pack, and understanding how to fix it, whatever the error may be, is the main focus of this tutorial.

This tutorial is designed to help you find and fix error messages that you may encounter. If you need to find a solution, you will likely find it here. I have helped many people with similar issues, and this tutorial has proven to be the most helpful resource in resolving error messages.

Video Guide

How to catch errors with VSCode

To utilize the Data-pack Helper Plus extension for VSCode, a convenient method to identify errors that might prove challenging to detect independently.

Take a screenshot of this by clicking on the symbol extensions on the left side of the bar in a red arrow. Once you download Visual Studio Code Studio, it is quite simple and visually pleasing.

Type data-pack into the search bar at the top, and Data-pack Helper Plus should appear as the first thing in the list.

Click Install in the extension page to install the extension, and VSCode will now help you find errors in your data pack!

Once the extension is installed, you can navigate to your data file on your computer and open it on the top window of your VSCode by clicking on File Open or pressing Ctrl+O on your keyboard.

If an error is found, it will be displayed at the bottom left corner of your window, next to the symbol ⊗. To open your files and read them in VSCode, click on this to see what the problem is! According to the information provided, there are no errors (it would display 3 ⊗ if there were 3 errors).

How to open the output log

It is possible that your game might still encounter validation issues or crash if VSCode does not assist in error identification or if you prefer using a different program like Notepad++ to write your code, which lacks error detection capabilities.

To figure out the problem, you need to read the errors sent there, open the log output of the game, and find a solution as to why it’s not working properly.

When you start the game next time, make sure to open the launcher and click on “Settings” in the bottom left corner. Then, enable the log output in the launcher before you start your game. Additionally, it is advisable to take a screenshot of the Java Edition Minecraft when it starts.

If the validation of the datapack fails, the error log will provide you with the necessary information. Therefore, you should try to load your datapack again and check the error message in the log output.

If you need to use a different world because the game doesn’t bother to check if you’ve changed the pack data, you won’t need to re-try the validation of the pack data every time, as long as the pack data has already failed validation.

Here is a compilation of the most frequent mistakes I have observed!

The data package does not appear after placing it in the data pack directory of the world.

The contents of pack.Mcmeta should appear like this. Make sure you have a folder called “pack” placed inside the “data” folder in your world’s “data” folder. Also, ensure that you have a file named “mcmeta.Pack” in that folder. The game won’t recognize the pack’s data if this file is missing or if there is something wrong with it. If you are experiencing problems with the location or contents of the file “mcmeta.Pack,” it is likely the source of the issue.

{
	"pack": {
		"pack_format": 7,
		"description": "This is an example data pack!"
	}
}

There was an error loading registry data: No key found in Map

Example: Error loading registry data: No key Properties in MapLike[{“Name

The initial three lines at the top are beneficial to you but may appear challenging to comprehend and appear as an extensive amount of text.

Failed to validate datapack
java.untill.concurrent.CompletionException:com.google.gson.JsonParseException: Error loading registry data: No key Properties in MapLike[{“Name”:”minecraft:grass_block”}]

The Failed to validate datapack portion simply indicates the nature of the error – there is an issue with the data pack.

This is not very helpful because it does not describe exactly what the error is. The JsonParseException com.Google.Gson.CompletionException: concurrent.Untill.Java tells you the nature of the error.

It ought to have indicated the necessary attributes, but failed to instruct the game to produce a grass block within your files. Consequently, if your error message states “No key Properties in MapLike[{“Name”:”minecraft:grass_block”}]”, it precisely identifies the nature of the error. This aspect is particularly beneficial as it provides an approximate indication of the location within your files where the issue arises, since the error will vary depending on the specific error encountered.

Basically, I should mention that the most common instances of this error can be caught using the Plus Helper Data-pack extension for VSCode. However, it is possible that this error could occur in other files as well, but it is most commonly encountered in the builder surface of files. This error indicates that something is missing somewhere, which means that there is an error.

The initial picture represents the code that caused the error, whereas the subsequent image displays the rectified code, featuring the inclusion of the crucial Properties within the curly bracket encompassing “Name”:”minecraft:grass_block”. The curly bracket holding “Name”:”minecraft:grass_block” encapsulates the insertion of the key Properties, while the corrected code corresponds to the second image, and the code responsible for the error corresponds to the first image.

An error occurred while loading registry data: Parsing of …. Failed.

Example: Error loading registry data: Failed to parse frost:worldgen/configured_feature/feature.Json file: com.Google.Gson.Stream.MalformJsonException: Unterminated object at

Similar to the previous mistake, the useful code is the initial four lines at the uppermost part.

Failed to validate datapack
java.untill.concurrent.CompletionException: com.google.gson.JsonParseException: Error loading registry data: Failed to parse frost:worldgen/configured_feature/feature.json file: com.google.gson.stream.MalformJsonException: Unterminated object at line 24 column 55 path $.config.decorator.type

The Failed to validate datapack part simply indicates the nature of the error – there is an issue with the data pack.

This is not very helpful because it does not describe exactly what the error is. The JsonParseException com.Google.Gson.CompletionException: concurrent.Untill.Java tells you the nature of the error.

Error loading registry data: Failed to parse frost:worldgen/configured_feature/feature.Json file tells what file the error is in, in this case the file data/frost/worldgen/configured_feature/feature.Json.

Of various age groups.

The error in line 24, column 55 of the file informs that there is an unterminated object in the parameter type inside the decorator in the config parameter of the file.

What is nice about it is that it tells you exactly where the problem is, whether it’s something obvious or something pretty that you can catch with the Plus Helper Data-pack.

The error is present in data/frost/worldgen/configured_feature/feature, as indicated in the file, within the config within the decorator within the type, just as mentioned in the error message.

This mistake can be easily identified, which makes it precisely what the mistake indicated. Since there is no visual cue, the sole method to determine this is by manual counting. Even though the only method to count this is manually, it is the 55th character from the left side of the window. Additionally, it is the 55th character from the left side of the window, despite the fact that the only way to count this is manually since there is no visual cue. Furthermore, it is the 55th character from the left side of the window, and it is the 55th character from the left side of the window, albeit the only method to count this is manually, as there is no visual cue. Moreover, it is the 55th character from the left side of the window, and it is the 55th character from the left side of the window, even though the only way to count this is manually since there is no visual cue. The mistake, which is a number 1 that should not be present.

Registry data loading error: Value not found ….

Example: Error loading registry data: Missing value: ResourceKey[minecraft:world

Similar to the previous three mistakes, the useful code refers to the initial three lines at the top.

Failed to validate datapack
java.untill.concurrent.CompletionException: com.google.gson.JsonParseException: Error loading registry data: Missing value: ResourceKey[minecraft:worldgen/configured_surface_builder / frost:icy_wastes]

The Failed to validate datapack part simply indicates the nature of the error – there is an issue with the data pack.

This is not very helpful because it does not describe exactly what the error is. The JsonParseException com.Google.Gson.CompletionException: concurrent.Untill.Java tells you the nature of the error.

This file does not exist, but it indicates what error the files are looking for – [minecraft:worldgen/configured_surface_builder/frost:icy_wastes] ResourceKey[value/Missing: data registry loading Error.

When you make a typo in a file or incorrectly name a file, an error occurs in this case – looking for a file on the surface of a builder that references another file.

If you encounter an error in one of your biomes utilizing that particular characteristic, you can readily identify the issue if the name it assigns is a misspelled variant of another file, like a feature. In this scenario, it should be simple for you to determine which file is corrupted, as the only type of file employing a surface builder is a biome file.

You can see the actual file called “icy:frost wastess” that exists on an extra end with, but the builder is looking for the icy:frost wastess surface for the builder surface. You can see that in the above picture example on the right.

Therefore, the document that the biome is searching for does not exist, which is what causes this error.

Java.Lang.NullPointerException.

Unlike the other errors listed here, there isn’t really any helpful code, but the first two lines tell you what went wrong.

Failed to validate datapack
java.untill.concurrent.CompletionException: java.lang.NullPointerException

The Failed to validate datapack part simply indicates the nature of the error – there is an issue with the data pack.

This is not very helpful because it doesn’t exactly describe the error. The NullPointerException in lang.Java: CompletionException.Concurrent.Untill.Java tells you the nature of the error.

Despite the fact that this error message does not assist you in locating the error, it still provides a clue as to what to search for. Based on my experience, this usually indicates that there is a typo somewhere and it may be quite difficult to identify. Simply review your files and check if there are any typos that VSCode has not detected. VSCode is not detecting those typos, so you need to examine your files thoroughly in order to identify them.

If you’re not sure whether you can go into a world and use cheats to locate all the official names of biomes, make sure to check here first. This error can occur, and it might only happen in this place. Instead of finding a savanna biome, you might come across a shattered savanna. Similarly, instead of encountering deltas, you might encounter basalt deltas. I have encountered these biomes multiple times.

Value … Beyond the specified range […].

Example: Error encountered while reading worldgen settings after loading data packs: Value 4.0 beyond the specified range of [

Unlike the other mistakes mentioned here, this one is not a validation error and occurs after the world is loaded.

Error reading worldgen settings after loading data packs: Value 4.0 outside of range [0.0:1.0]

The parameter offset, which shows the example image on the left, allows a range of 4 to be set. This error message is telling you that the number should only be between 1.0 and 0.0, and it should only be in one of your files somewhere.

In order to locate the potential error, please search for each occurrence of the numerical value that triggers the error (in this case, search for the numeral 4). I recommend using the Ctrl/Cmd + f function as the error does not provide any clues regarding the specific location of the error within your data pack.

This is the page dedicated to biomes, and this is the page dedicated to dimensions: the official Minecraft wiki is a valuable resource to discover the limits that the game permits if you are unaware of the accepted ranges.

Example:Unknown block type ‘minecraft:’ at position 0

Your game will indeed crash, and this particular issue will remain undetected during data pack verification, unlike all the other errors mentioned in this list.

Encountered an unexpected exception
Z: Feature placement
	...
Caused by: java.lang.RuntimeException: com.mojang.brigadier.exceptions.CommandSyntaxException: Unknown block type ‘minecraft:’ at position 0: <--[HERE]

The Unexpected Exception Encountered section simply indicates that something unexpected occurred.

Something went wrong during the placement of the prearranged attribute or structured pattern, as evidenced by the positioning of the feature.

The error is caused by a java.RuntimeException: com.Mojang.Brigadier.Exceptions.CommandSyntaxException, which tells you the nature of the error. However, it is not very helpful as it does not provide a description of the exact error. On the other hand, the message "Unknown block type 'minecraft:' at position 0" precisely indicates that the issue lies in the game's inability to recognize a block at a specific location. So, the problem is that the game cannot identify a block, and this is clearly stated in the error message. Although it does not provide the exact error description, it does convey the nature of the error - Caused: by java.RuntimeException: com.Mojang.Brigadier.Exceptions.CommandSyntaxException.

In this Minecraft example, 'minecraft:WafflesAreBetter' is recognized as a super cool block type called 'block Unknown' instead of the valid block type 'minecraft:'.

It is likely that the error is caused by a NullPointerException in the java.Lang pack. However, it is also possible that this error is caused by the files in the data pack, specifically the blocks inside the jigsaw structure of the nbt files. Usually, I have only experienced this error as a random typo.

Examine all the puzzle pieces that may contain this spelling error to locate the issue. For instance, if you mistakenly spelled netherrack with just one r (Unknown block type 'minecraft:netherack'), then you only need to verify the jigsaws that transform into netherrack, not those that transform into any other block.

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