[MC-129383] Loading 18w16a worlds in 18w19b: [WorldGen-Worker-1/ERROR]: Couldn't load chunk

This

[11:04:26] [WorldGen-Worker-1/ERROR]: Couldn't load chunk
java.lang.NullPointerException: null

Millions of times.

When loading a world from 18w16a

Examining the log further...

[11:03:24] [Server thread/ERROR]: Couldn't load chunk
java.lang.NullPointerException: null
	at bqt.<init>(SourceFile:70) ~[minecraft_server.18w19b.jar:?]
	at bpl.c(SourceFile:627) ~[minecraft_server.18w19b.jar:?]
	at java.util.HashMap.computeIfAbsent(Unknown Source) ~[?:1.8.0_171]
	at bpl.a(SourceFile:627) ~[minecraft_server.18w19b.jar:?]
	at bpx.a(SourceFile:455) ~[minecraft_server.18w19b.jar:?]
	at bpx.a(SourceFile:150) ~[minecraft_server.18w19b.jar:?]
	at bpx.a(SourceFile:98) ~[minecraft_server.18w19b.jar:?]
	at si.g(SourceFile:94) [minecraft_server.18w19b.jar:?]
	at si.b(SourceFile:118) [minecraft_server.18w19b.jar:?]
	at si.a(SourceFile:160) [minecraft_server.18w19b.jar:?]
	at net.minecraft.server.MinecraftServer.g_(SourceFile:384) [minecraft_server.18w19b.jar:?]
	at net.minecraft.server.MinecraftServer.a(SourceFile:336) [minecraft_server.18w19b.jar:?]
	at ru.d(SourceFile:247) [minecraft_server.18w19b.jar:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:497) [minecraft_server.18w19b.jar:?]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_171]

Linked issues

is duplicated by 11

MC-129366 Missing water in chunks on new 18w19b worlds Resolved

MC-129368 World save only converts some chunks in world spawn from 18w16a to 18w19b Resolved

MC-129369 Loading world from 18w16a only recreates world without buildings Resolved

MC-129381 World loading from 18w16a creates a clear world without anything that i built. Resolved

MC-129389 Server Crashes When Loading 18w16a World Resolved

6 more links

Attachments

latest.log

Comments 16

Alawnely 2018-05-09T15:13:41Z

Attached log file

Jonathan Widén 2018-05-09T16:14:31Z

Confirmed for singleplayer aswell as on servers

Andy (Romaq) Smith 2018-05-09T18:12:03Z

Confirmed on Vanilla Java, I can provide a screenshot if appropriate.

Luke Synnestvedt 2018-05-09T18:15:03Z

Crashed as soon as I attempted to load our previous 18w16a world onto the updated server. Any progress on causes or fixes?

kumasasa 2018-05-09T18:16:42Z

See here https://twitter.com/ProfMobius/status/994186578611273728

After investigating the problem, snapshot worlds pre 16a will load properly. 16a worlds are still broken. A fix is in the pipeline.

6 more comments

Brock Lievsay 2018-05-11T01:47:32Z

another possible fix I'm about to test out of curiosity just in case they don't fix it to load 18w16a worlds: load your 18w16a world in 18w15a. I did so on a copy of my map, and thus far, I do not see anything missing or broken ( at least for the blocks that are in my map anyways) . I will check the whole map, travel the entire map, to resave all chunks and attempt to load the world in 18w19b. I'll update when I've tested this out.

Edit: Pretty promising results! only one area that must not have gotten saved in 18w15a or for whatever reason didn't load in 18w19b. Way way way better than what I got when I originally loaded the 18w16a world in 18w19b

This is the only area of missing chunks that I've found with a brief search.

[media]

I remember flying very fast over this area, faster than minecraft could load the chunks at times.
Its probable that minecraft didn't load these chunks in time. But honestly, If this is all I'm missing, It would be pretty easy to /fill it back in since it was water anyways. I should try manually updating those chunks in 18w15a again and see if it changes anything with those chunks.

Linda A. Wingfield 2018-05-11T02:41:58Z

Brock Lievsay! Thank you! 👍 I tried all sorts of stuff last night for my single-player 18w16a world...except that workaround that you just mentioned! I should have thought of that! I was definitely able to load an 18w15a world into 18w19b, so I will give this a try later tonight. 😃

Linda A. Wingfield 2018-05-11T02:42:59Z

Also, Thank you, [Mod] Kumasasa! So glad a fix is in the pipeline.

Linda A. Wingfield 2018-05-11T04:05:27Z

In Vanilla, I did open the 18w16a world I wanted to be getting on with, in 18w15a, and it opened fine and everything seemed to be the way I left it as far as having played it, at least. I made sure I was in the spawn area before saving in 18w15a. Then I went into 18w19b and brought it up. NOPE! It opened, but went into the routine of "preparing spawn," and once that was over, it "loaded terrain," but...every trace of world development was completely gone.

I tried again, using 18w14a. Again, it was all fine, as to played areas and development. Saved in 18w14a, quit, opened 18w19b, and opened the world again. Repeat of the performance with the 18w15a save.

SIGH...

Now waiting for the pipelined fix for the problem.

Brock Lievsay 2018-05-11T19:47:02Z

@Linda A. Wingfield Hmm.. that's strange. I just tried again with my world, and I cannot see any missing chunks at all in my map. Is your world type default or something? My world type is a superflat ocean world with custom terrain that I painted in world painter back in 1.11.2, in which the world size is 266 MB (It's a huge land mass). Keep in mind that minecraft only rewrites chunks of the world that have been loaded in game. Basically when I loaded my world in 18w15a, I set my render distance to 16 chunks and flew across the map back and forth working my way north with an elytra with the goal to have minecraft load every chunk in my world, which did the trick for me. On my second attempt, I manually placed a few blocks in the chunks that didn't load on my first attempt of conversion just in case. They are there now. Don't know if the world type has anything to do with this though. I think I might generate a new 18w16a default type world, blow some craters, and see if I can get it to load in 18w19b

Matthijs Eijgenraam 2018-05-12T14:41:14Z

Can confirm in 18w19b vanilla server.

Windows 10 Pro 16299.431 x64

Java 1.8.0_171-b11

Glad I ran a world backup. I hope the team can come up with a fix.

Grigory Evropeytsev 2018-05-14T18:35:23Z

I have a similar problem to one commented by @Linda A. Wingfield. When I open the world from 18w16a in 18w19b the world regenerates. Player inventory is fine, but every progress is gone. The world is as it looked when created.

Using the workaround, world opens fine in 18w15a, but when opened in 18w19b, some chunks are converted fine, and others are regenerated.

Tried several times with the same result. By placing a block in 18w15a, ensures that the chunk got converted fine to 18w19b.

The world is a default world created in 18w11a.

Brock Lievsay 2018-05-15T00:27:45Z

Yeah, It looks like my work around still works in default world types, but just not as well..(Unless I just got lucky with my superflat map) It took me a few tries to get all of the built chunks in a default world type to convert. Basically I hovered/ flew over everything once in 18w15a, and then made a copy of that save. Loaded the copy in 18w19b and made note of what chunks have been reset. I then went back into the original reverted save and revisited the noted chunks with special emphasis. Upon loading a new copy of that in 19b, The revisited chunks have always been there. Repeat as many times as necessary. Or, to guarantee your chunk to convert, place a block and break it or use a command block or function to do this for you faster.

Braxton Spence 2018-05-16T18:58:45Z

I have also been having problems with this, including in 18w20b. World save from 18w16a gives the same NullPointerException thousands of times.

[Mod] Neko 2018-06-24T01:21:39Z

The "Couldn't load chunk" error no longer appears when upgrading an 18w16a world to 1.13-pre3. I'm getting "Failed to save chunk" now but that seems to be MC-131088.

Meri Diana 2018-11-08T10:00:43Z

I'm getting a "Couldn't load chunk java.lang.NullPointerException" error (78 times) in one of my resource pack test worlds (Custom Flat Void with barrier blocks as floor), I currently don't know why.
The last version I've been in in this world was 18w44a, and I can't remember those errors to show up in the game output in 44a.

I tested 6 different worldsaves, of those 6 so far 3 have been affected; in two worldsaves (regular Minecraft worlds) I've been the last time in version 18w43b, and it returns 113 errors for one, and 195 of the same errors for the second worldsave. Upon re-entering those affected worldsaves in 18w45a, the errors don't show up anymore in the game output.

Sadly I haven't backed up the first affected worldsave before I entered it (the one I've been last time in 18w44a), but I did with the two others (entered last time in 18w43b, ~4MB + ~18MB backup size).

The errors are reproducable with those backups/show up again when entered directly from 18w43b to 18w45a, as well as if you load them at first in 18w44a (no errors show up), then move on to 18w45a (errors in output).

I also just freshly created a random, regular Minecraft world in 1.13.2, went into it in 18w45a, and get 100 of those errors. I've made a backup of that new 1.13.2 world before I entered it in the current snapshot.

If screenshots of either the error messages or a copy of the worldsaves (also of the one I don't have an earlier backup of) is needed, let me know.