[SOLVED] [1.12] Server Crash when removing dimension (NullPointerException)

[Rurido]

I try to remove dimensions (custom, not -1/0/1). After it was successfully removed, the server crashes. I think I forgot one thing but I can't figure out what.
 

This is the remove-code:

/*some imports*/
import net.minecraftforge.common.DimensionManager;
import /*my package*/.util.LogHelper;

public class Dimensions {

/*some stuff*/

public static boolean removeDimension(int id) { if(!DimensionManager.isDimensionRegistered(id)) return false;
    try { LogHelper.info("Unloading dimension " + id);
        DimensionManager.unloadWorld(id);
    }catch (Exception ex){ LogHelper.warn(ex.getMessage());
    } try { LogHelper.info("Unregistering dimension " + id);
        DimensionManager.unregisterDimension(id);
    }catch (Exception ex){ LogHelper.error(ex.getMessage());
        return false;
    } LogHelper.info("Removing dimension " + id + " from data storage");
    if( !DimensionDataStorage.removeDimension(id) ){ //<---DimensionDataStorage extends WorldSavedData LogHelper.warn("Could not delete data from DimensionDataStorage. This occurs if no data was found.");
        return false;
    } LogHelper.info("Dimension " + id + " successfully removed");
    return true;
}

 

Crash Log after calling removeDimension(id[=3]):

Spoiler

...nothing special above...
[22:47:43] [Server thread/INFO] [RR55's Server+]: Unloading dimension 3
[22:47:43] [Server thread/INFO] [RR55's Server+]: Unregistering dimension 3
[22:47:43] [Server thread/INFO] [RR55's Server+]: Removing dimension 3 from data storage
[22:47:43] [Server thread/INFO] [RR55's Server+]: Dimension 3 successfully removed
[22:47:43] [Server thread/ERROR]: Encountered an unexpected exception
java.lang.NullPointerException: null
	at net.minecraftforge.common.DimensionManager$Dimension.access$200(DimensionManager.java:60) ~[DimensionManager$Dimension.class:?]
	at net.minecraftforge.common.DimensionManager.unloadWorlds(DimensionManager.java:332) ~[DimensionManager.class:?]
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:857) ~[MinecraftServer.class:?]
	at net.minecraft.server.dedicated.DedicatedServer.updateTimeLightAndEntities(DedicatedServer.java:409) ~[DedicatedServer.class:?]
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:740) ~[MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:589) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_121]
[22:47:43] [Server thread/ERROR]: This crash report has been saved to: [I don't think you need this ^^]
[22:47:43] [Server thread/INFO]: Stopping server
[22:47:43] [Server thread/INFO]: Saving players
[22:47:43] [Server thread/INFO]: Saving worlds
[22:47:43] [Server thread/INFO]: Saving chunks for level 'world'/overworld
[22:47:43] [Server thread/INFO]: Saving chunks for level 'world'/the_nether
[22:47:44] [Server thread/INFO]: Saving chunks for level 'world'/the_end
[22:47:44] [Server thread/INFO]: Saving chunks for level 'NewWorld'/custom
[22:47:45] [Server thread/INFO] [FML]: Unloading dimension 0
[22:47:45] [Server thread/INFO] [FML]: Unloading dimension -1
[22:47:45] [Server thread/INFO] [FML]: Unloading dimension 1
[22:47:45] [Server thread/INFO] [FML]: Unloading dimension 3
[22:47:45] [Server thread/INFO] [FML]: Applying holder lookups
[22:47:45] [Server thread/INFO] [FML]: Holder lookups applied
[22:47:45] [Server thread/INFO] [FML]: The state engine was in incorrect state SERVER_STOPPING and forced into state SERVER_STOPPED. Errors may have been discarded.

 

It looks like the dimension still exists after removing it; but when I restart the server it is gone exept that if I create a new dimension it's id is the id of the removed dimension +1, that's why the id is 3 and not 2 . Also the DIM[ID] folder is not beeing deleted.

 

Any Idea what I forgot to add [or rather remove ^^]?

Edited November 13, 2017 by Rurido

[Rurido]

Adding them works just fine, no errors, nothing.

 

My approach:

Spoiler

public class Dimensions {
	public static DimensionType dimensionType;

	public static void init() {
		dimensionType = DimensionType.register("custom", "_custom", 5, CustomWorldProvider.class, false);
		for (Integer id : DimensionDataStorage.instance().getDimensions()) {
			LogHelper.info("Loading Dimension " + id);
			if (!DimensionManager.isDimensionRegistered(id)) {
				DimensionManager.registerDimension(id, dimensionType);
			}
		}
	}
	
	public static void createDimension(String name, long randomSeed, boolean mapFeaturesEnabled, WorldType terrainType, String generatorOptions){
		int id = DimensionManager.getNextFreeDimId();
		CustomWorldInfo info = new CustomWorldInfo(DimensionManager.getWorld(0).getWorldInfo(), name, randomSeed, mapFeaturesEnabled, terrainType, generatorOptions);
		DimensionDataStorage.instance().setDimensionData(id, info.cloneNBTCompound(null));
		DimensionManager.registerDimension(id, dimensionType);
		DimensionManager.initDimension(id);
		WorldServer world = DimensionManager.getWorld(id);
		world.initialize(new WorldSettings(info));
	}

	public static boolean removeDimension(int id) {
		/*see above*/
	}
}

@Mod(modid = Main.MODID, version = Main.VERSION)
public class Main {
	/*some stuff*/	
	@EventHandler
	private void serverStarting(FMLServerStartingEvent event) {
		CommandManager.instance().initCommands(event);
		DimensionDataStorage.init(event.getServer().worlds[0]);
		Dimensions.init();

		/*some other stuff*/
	}
}

public class CommandWorld extends CommandBase{
	/*some stuff*/
	@Override
	public void execute(...) throws CommandException {
		/*some argument stuff*/
		Dimensions.createDimension(args[1], seed, mapFeaturesEnabled, WorldType.DEFAULT, generatorSettings);
	}
}

 

 

So i thought removing them would be also that easy.

Well if it CAN NOT be done, the server crash is "not a bug" but "a feature"...

[Rurido]

If you call this a terrible hack, okay...
And there is not "another terrible hack" to remove them?

[Rurido]

20 minutes ago, diesieben07 said:

28 minutes ago, Rurido said:

If you call this a terrible hack, okay...

Please clarify what you mean by "this". I am talking about EnumHelper. And you?

You said:

1 hour ago, diesieben07 said:

Since dimensions are an enum now (DimensionType) you cannot reasonably remove them. Even adding them requires a giant, terrible hack.

 

Well, i never use the EnumHelper directly. It is used by DimensionType.register(...) but I don't want to remove (or add) DimensionTypes - I only do this once for all my custom dimensions which use all the same type:

My code:

public static DimensionType dimensionType; //<--- I could make it final, because it is only initialized once at FMLServerStartingEvent
/*...*/
dimensionType = DimensionType.register("custom", "_custom", 5, CustomWorldProvider.class, false);

Minecraft's source: net.minecraft.world.DimensionType:

public static DimensionType register(String name, String suffix, int id, Class<? extends WorldProvider> provider, boolean keepLoaded){
	String enum_name = name.replace(" ", "_").toLowerCase();
	DimensionType ret = net.minecraftforge.common.util.EnumHelper.addEnum(DimensionType.class, enum_name, ENUM_ARGS, id, name, suffix, provider);
	return ret.setLoadSpawn(keepLoaded);
}

 

So as I said, i don't want to remove the entire type, I just want to remove some dimensions (all of my custom type tho).

 

I really think we talk past each other

Edited November 11, 2017 by Rurido

[Rurido]

I don't know if my way creating dimensions is right, but I do use one DimensionType for multiple dimensions  and all of them work fine:
Screenshot: https://rurido.de/temp/mc_dim_list.png (Post was too long)

[19:39:12] [Server thread/INFO] [RR55's Server+]: WorldInfo set on dimension 2
[19:39:12] [Server thread/INFO] [FML]: Loading dimension 2 (Test1) (net.minecraft.server.dedicated.DedicatedServer@2f011051)
[19:39:15] [Server thread/INFO] [RR55's Server+]: WorldInfo set on dimension 3
[19:39:15] [Server thread/INFO] [FML]: Loading dimension 3 (Test2) (net.minecraft.server.dedicated.DedicatedServer@2f011051)
[19:39:18] [Server thread/INFO] [RR55's Server+]: WorldInfo set on dimension 4
[19:39:18] [Server thread/INFO] [FML]: Loading dimension 4 (Test3) (net.minecraft.server.dedicated.DedicatedServer@2f011051)
[19:39:20] [Server thread/INFO] [RR55's Server+]: WorldInfo set on dimension 5
[19:39:20] [Server thread/INFO] [FML]: Loading dimension 5 (Test4) (net.minecraft.server.dedicated.DedicatedServer@2f011051)

 

So I would say that a DimensionType can be used for ore than one Dimension, because as I understand it, DimensionTypes don't say "what dimension are you?" but "what kind of dimension are you?". But I can also be wrong

 

[Rurido]

17 minutes ago, diesieben07 said:

But I might be wrong here, and type IDs and dimension IDs are separate.

If the comment above the function is right, then you are wrong, idk...

I give a DimensionType (which can also be identified by its id), and get a list of dimension ids...

package net.minecraftforge.common;

public class DimensionManager{
  	/*...*/
  
	/**
	 * Returns a list of dimensions associated with this DimensionType.
	 */
	public static int[] getDimensions(DimensionType type){
		int[] ret = new int[dimensions.size()];
		int x = 0;
		for (Map.Entry<Integer, Dimension> ent : dimensions.entrySet()){
			if (ent.getValue().type == type){
				ret[x++] = ent.getKey();
			}
		}

		return Arrays.copyOf(ret, x);
	}
  	/*...*/
}

 

 

Edited November 12, 2017 by Rurido

[Rurido]

I never wanted to remove a DimensionType. I want to remove a Dimension (by its id)!

21 hours ago, Rurido said:

So as I said, i don't want to remove the entire type, I just want to remove some dimensions (all of my custom type tho).

 

23 hours ago, Rurido said:

I try to remove dimensions (custom, not -1/0/1).

 

[Rurido]

Do I have to use the event (I found WorldEvent.Unload) or can i force te dimension to unload immediately?

[Rurido]

I see...

if(w == null || !ForgeChunkManager.getPersistentChunksFor(w).isEmpty() || !w.playerEntities.isEmpty() || dimension.type.shouldLoadSpawn()){
	FMLLog.log.debug("Aborting unload for dimension {} as status changed", id);
	continue;	
}

Well, i can teleport all players out of this dimension so that this list would be empty.

I also found ForgeChunkManager.unloadWorld(World world) which removes its  persistent chunks (forcedChunks.remove(world);) so that

public static ImmutableSetMultimap<ChunkPos, Ticket> getPersistentChunksFor(World world){
	return forcedChunks.containsKey(world) ? forcedChunks.get(world) : ImmutableSetMultimap.<ChunkPos,Ticket>of();
}

would  return an empty set.

The spawn is not marked as "keep loaded" by my DimensionType.

 

At last i would steal some code from DimensionManager.unloadWorlds(...); to get

WorldServer w = worlds.get(id);
MinecraftForge.EVENT_BUS.post(new WorldEvent.Unload(w));
w.flush();
setWorld(id, null, w.getMinecraftServer());

which should unload it immediately  if i got things right.

But isn't there a more elegant way or do I have to to all steps by myself?

 

[Rurido]

Is there a way to check if a dimension is already unloaded? (if the dimension should be deleted before it was loaded e.g. when no player joined the world yet)

 

EDIT:

nvm, I found a way:
 

for(Integer i : DimensionManager.getIDs()){
	if(id == i){ //Dimension is loaded.
		return false;  //queued
	}
}
//Dimension is not loaded
//continue

 

Edited November 13, 2017 by Rurido

[Rurido]

Thx.

Quote

can't see the wood for the trees....

Edited November 13, 2017 by Rurido