kjiang

Related: MC-132776.

I can confirm that this bug exists. Attached is my crash report when trying to duplicate it.

You need to make sure your game language is set to "Chinese (Simplified)" first (简体中文 中国). And then just delete any one of the single play saved world in game, the game crashed.

Tested on:

1.13-pre6

System Ubuntu 16.04.4 LTS (with locale zh_CN.UTF-8 properly installed)

Launcher 1.6.89-j

After 3 days of testing, although my server still throw this warning to me occasionally:

[21:19:09] [Netty Server IO #3/WARN]: Selector.select() returned prematurely 512 times in a row; rebuilding Selector io.netty.channel.nio.SelectedSelectionKeySetSelector@b338db7.
[21:19:09] [Netty Server IO #3/INFO]: Migrated 3 channel(s) to the new Selector.

Good news is no more player is kicked or prevented. The newer version of netty seems working again.

For the warning it self, I did some dig in about this. Founds out that it looks like that there might be something to do with incompatibility with certain version of kernel and netty. However my kernel is 4.4.0 running Ubuntu 16.04LTS which should be pretty main-stream at this moment, so more people must be affected by this (even though 4.1.11 don't kick player anymore). But what really bugs me is that this issue was first reported way before 4.0.22. Remember, we didn't have such a problem before 1.12 when Minecraft was using netty 4.0.23 by then. My guess is there should be more bugs in netty which should be fixed before it breaks things again.

I highly suggest that people who working at Mojang should not only upgrade netty to a newer version, but report the warning to the netty project team as well. Only you guys can do it because we don't have access to the minecraft code and we can not debug with it.

Thank all of you for the consideration and effort!

It takes several days on testing since the issue occurs randomly (depending on how and how many player join). So I will report our results on Monday or if it breaks.

For those who need to run cb/spigot, here is the command you need:

java -server -Xmx2G -cp netty-all-4.1.11.Final.jar:spigot-1.12.jar org.bukkit.craftbukkit.Main

It has NO guarantee. I'm not working for Mojang or Spigotmc, so good luck to you! (and me lol)

(https://bugs.mojang.com/browse/MC-118733)
The same issue here, it keeps happening to me for days and several times! It is totally unacceptable for any servers like us which are supposed to provide stable and meaningful service to the public. Just take a simple look at https://bstats.org/global/bukkit you will find that over 80% of server are running on an Unix-like system. It means that those server, including some big networks, will never have a chance to upgrade to 1.12 if it is not fixed!

I believe it is very simple to fix this issue: just upgrade netty to 4.1.10 version (see https://github.com/netty/netty/issues/6607 ).
If this issue could not be fix, or at least provide some temporary solutions for people, I have no choice but to downgrade my whole network back to 1.11.2.

https://hub.spigotmc.org/jira/browse/SPIGOT-3346
Spigot has nothing to do with netty because they did not touch it at all. And, as I said, the netty package is provided directly by the official libraries.

Just by simply google the exception you might find this interesting issue:
https://github.com/netty/netty/issues/6607

As far as I know 1.12 using netty 4.1.9. So you might need to upgrade the netty library to 4.1.10 with the official server software.