Stack trace I got (a few of them):
java.util.ConcurrentModificationException: null java.util.ConcurrentModificationException: null at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1388) ~[?:1.8.0_202] at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580) ~[?:1.8.0_202] at net.minecraft.server.world.ServerLightingProvider.method_17312(ServerLightingProvider.java:135) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?] at net.minecraft.server.world.ServerLightingProvider.runTasks(ServerLightingProvider.java:170) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?] at net.minecraft.server.world.ServerLightingProvider.method_17313(ServerLightingProvider.java:108) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?] at net.minecraft.server.world.ChunkTaskPrioritySystem.method_17634(ChunkTaskPrioritySystem.java:58) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?] at net.minecraft.util.thread.TaskExecutor.runNext(TaskExecutor.java:94) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?] at net.minecraft.util.thread.TaskExecutor.runWhile(TaskExecutor.java:137) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?] at net.minecraft.util.thread.TaskExecutor.run(TaskExecutor.java:105) ~[minecraft-1.16.4-projectmapped-net.fabricmc.yarn-1.16.4+build.7-v2.jar:?]Using fabric here, but its better that then nothing. Its all from vanilla classes
Comments 4
Well, just happened randomly when I was testing some datapack driven world generation. The inspecting of the stack trace revealed that it has nothing to do with modding in this case, and I thought if might be helpful to post a stack in here - should be fairly easy to find that spot in the original code and inspect for potential concurrency issues.
As most issues with concurrent stuff - they are sparse and far in between and hard to catch.
The only thing, as I said, that might be relevant is I was running a heavy worldgen datapack in that world. (Starmute terralith) that may have exposed some issues with lighting chunks
Hey there!
This report is invalid as fabric has been used when this issue occurred. Just to let you know, the bug tracker only handles issues relating with unmodified game versions.