The bug
Worlds that have an unknown version now show the latest version (currently 20w18a).
Opening such a world causes lots of errors to be logged and corrupts the world:
20w18a
Couldn't load chunk [-9, 23]
java.lang.NullPointerException
at cgo.a(SourceFile:122)
at cgo$$Lambda$3404/1324669015.accept(Unknown Source)
at cgu.a(SourceFile:249)
at cgu$$Lambda$3406/19164340.accept(Unknown Source)
at it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap$MapEntrySet.forEach(Int2IntOpenHashMap.java:927)
at cgu.a(SourceFile:249)
at cgo.h(SourceFile:121)
at cgz.a(SourceFile:101)
at yf.l(SourceFile:525)
at yf$$Lambda$3328/1853807856.get(Unknown Source)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1582)
at alu.c(SourceFile:144)
at yr$a.c(SourceFile:540)
at alu.w(SourceFile:118)
at yr$a.w(SourceFile:549)
at yr.d(SourceFile:280)
at net.minecraft.server.MinecraftServer.bc(SourceFile:777)
at net.minecraft.server.MinecraftServer.w(SourceFile:765)
at alu.c(SourceFile:127)
at net.minecraft.server.MinecraftServer.v(SourceFile:750)
at net.minecraft.server.MinecraftServer.b(SourceFile:532)
at net.minecraft.server.MinecraftServer.i_(SourceFile:372)
at enx.d(SourceFile:65)
at net.minecraft.server.MinecraftServer.run(SourceFile:673)
at java.lang.Thread.run(Thread.java:745)
Note: It appears this does not affect worlds in the "Region file format" (before release 1.2.1).
Reproduction steps
Start a world in any version before 1.9, or download the attached
Copy the world to the
saves
folder of the current versionOpen the world selection in the current version
Related issues
Attachments
Comments

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