I have a few village buildings I have put in the “world/generated” folder, when updating to Minecraft 1.21.5, a massive error is thrown in console regarding a structure and casting:
”class com.mojang.datafixers.util.Either$Left cannot be cast to class com.mojang.datafixers.util.Pair” (short version)
Latest log and “generated” folder (zipped) have been provided!
Steps to reproduce:
start up server then stop server
unzip/add generated folder to world folder
start up server again
if the error is not throw right away, join server, run command
/locate structure minecraft:village_plainsand teleport to said village
Environment
OS = macOS 15.3.2
Java = OpenJDK 64-Bit Server VM Temurin-22.0.2+9 (build 22.0.2+9, mixed mode)
Minecraft = 1.21.5 (server)
Update:
I did lots of testing and ran some files in an NBT reader and came to the conclusion that the structures that cause the error are ones with signs, more so its signs that have outdated NBT before “front_text” and “back_text” were used.
These signs had the old NBT fields “Line1”, “Line2” and so on.
Exhibit A:
[media]Going back on 1.21.4 I attempted to run “forceUpgrade”, that unfortunately does not appear to upgrade files in the “generated” folder.
Good news: I can go back onto 1.21.4 into my world I have specifically for those structures, and re-save each structure that has those signs, therefore forcing the NBT to update in the files. I can then load these structures in 1.21.5 no problem.
Bad news: Obviously that error shouldn't be happening.