[MC-9211] Client crash when sending two objective-creation packets with the same name

I fully realize this may be a silly bug report; a crash like this is likely fully normal for a development snapshot (and this one in particular even useful while debugging the scoreboard). Making sure it doesn't slip through to final release regardless.

If you send two scoreboard objective-creation packets to the client with the same objective names, the game will crash with an IllegalArgumentException referencing the duplicate objective

Quick edit here: The game also crashes if an objective-deletion packet with a name unknown to the client is received, however the game does not crash if you send a scoreboard display packet with a name unknown to the client.

Linked issues

is duplicated by 6

MC-12930 Crash Report Resolved

MC-14900 Scoreboard causes client crash due to duplicate objectives with the same name. Resolved

MC-22842 Crash because of 'exception of world tick' Resolved

MC-27820 Ticking screen Resolved

MC-34049 minecraft server crash Resolved

1 more links

relates to 1

MC-18738 IllegalStateException: Player is either on another team or not on any team. Resolved

Attachments

crash-2013-02-04_22.24.42-client.txt

Comments 11

kumasasa 2013-02-05T07:30:40Z

Note:

Description: Exception in world tick
java.lang.IllegalArgumentException: An objective with the name 'Test' already exists!
	at aqs.a(SourceFile:30)
	at bcj.a(SourceFile:1063)
	at fa.a(SourceFile:43)

Tails 2013-02-05T14:37:59Z

Please do not mark issues as private, unless your bug report is a security issue containing information that may compromise your server/client.

Connor James 2013-02-10T05:39:40Z

Affects 13w06a as well.

Nathan Adams 2013-02-28T13:02:47Z

Unless you can replicate this in vanilla, there is no issue. It is your duty, if you're sending custom packets, to remember what the client knows about already.

James Waterhouse 2013-04-29T17:00:34Z

These are valid packets used by the Bukkit API, do you suggest this bug is taken to them instead?

1 more comments

Nathan Adams 2013-04-29T17:14:04Z

This is 100% absolutely a bug with Bukkit. They should be tracking which players know about which objectives, and not send two different objectives with the same name - doing so can either cause huge screwups, or I can make it catch this early and tell you about it (this is what it does now). I think the catching it earlier is the best solution.

Connor James 2013-04-29T17:18:53Z

(to be clear, if you're using the supported Bukkit Scoreboard API you won't get this crash)

James Waterhouse 2013-04-29T17:21:38Z

I will report this to bukkit, but to be clear I am using the supported Bukkit scoreboard API, and I still get this crash. This may be paritally due to the fact we are using a proxy as well, so I'm sure this may neither be a bukkit bug.

Nathan Adams 2013-04-29T17:25:42Z

If it's not Bukkit then it could very well be your proxy. At the end of the day, something is telling the client "I have a whole new thing called xxxx" and this is not allowed and would cause big bugs if we had not caught it first, so it's working as intended on our end.

James Waterhouse 2013-04-29T17:33:18Z

Ok, thanks you for the quick response time, much appreciated.