server - match crashed

[xenohedron]

Reported in match chat, right after a spectator stopped watching from lost connection, although player (tiera3) had priority on declare blockers step, could not select a blocker.

Attempted rollback did not have any visual effect.

Interesting game log message before we gave up

Starting a new client did not help obtain a playable game state.

Server logs excerpt:

INFO  2024-10-17 20:50:19,818 LOST CONNECTION - YamiKuriboh [Watch: 1 ] at 81.170.109.140, sessionId: 5c4o11l-53q00u-m2drqvy7-1-m2drqw5q-4 =>[Timer-0] Main$MageServerConnectionListener.handleConnectionException 
WARN  2024-10-17 20:50:19,820 SESSION CALLBACK EXCEPTION - java.io.IOException: Connection is closed, userId b7841e30-d89a-4f10-893d-0c6395be5cb1, messageId: 259 =>[GAME adafb548-125f-4cba-8df2-97a233f23f05] Session.fireCallback 
FATAL 2024-10-17 20:50:19,840 GameWorker system error [adafb548-125f-4cba-8df2-97a233f23f05 - Two Player Duel; T10.DB; active: xenohedron; stack: 0]: java.util.ConcurrentModificationException =>[GAME adafb548-125f-4cba-8df2-97a233f23f05] GameWorker.call 
java.util.ConcurrentModificationException
	at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:911)
	at java.util.ArrayList$Itr.remove(ArrayList.java:875)
	at mage.server.User.onLostConnection(User.java:201)
	at mage.server.SessionManagerImpl.lambda$disconnect$1(SessionManagerImpl.java:130)
	at java.util.Optional.ifPresent(Optional.java:159)
	at mage.server.SessionManagerImpl.disconnect(SessionManagerImpl.java:129)
	at mage.server.Session.fireCallback(Session.java:457)
	at mage.server.User.lambda$fireCallback$0(User.java:261)
	at java.util.Optional.ifPresent(Optional.java:159)
	at mage.server.User.fireCallback(User.java:260)
	at mage.server.game.GameSessionWatcher.lambda$inform$1(GameSessionWatcher.java:61)
	at java.util.Optional.ifPresent(Optional.java:159)
	at mage.server.game.GameSessionWatcher.inform(GameSessionWatcher.java:61)
	at mage.server.game.GameController.informOthers(GameController.java:921)
	at mage.server.game.GameController.perform(GameController.java:1033)
	at mage.server.game.GameController.perform(GameController.java:1012)
	at mage.server.game.GameController.select(GameController.java:888)
	at mage.server.game.GameController.lambda$init$3aa0d15c$2(GameController.java:197)
	at mage.game.events.EventDispatcher.fireEvent(EventDispatcher.java:28)
	at mage.game.events.PlayerQueryEventSource.select(PlayerQueryEventSource.java:50)
	at mage.game.GameImpl.fireSelectEvent(GameImpl.java:3006)
	at mage.player.human.HumanPlayer.selectBlockers(HumanPlayer.java:2077)
	at mage.game.combat.Combat.selectBlockers(Combat.java:667)
	at mage.game.combat.Combat.selectBlockers(Combat.java:632)
	at mage.game.turn.DeclareBlockersStep.beginStep(DeclareBlockersStep.java:37)
	at mage.game.turn.Phase.prePriority(Phase.java:189)
	at mage.game.turn.Phase.playStep(Phase.java:203)
	at mage.game.turn.Phase.play(Phase.java:91)
	at mage.game.turn.Turn.play(Turn.java:137)
	at mage.game.GameImpl.playTurn(GameImpl.java:1152)
	at mage.game.GameImpl.play(GameImpl.java:1059)
	at mage.game.GameImpl.start(GameImpl.java:1035)
	at mage.server.game.GameWorker.call(GameWorker.java:35)
	at mage.server.game.GameWorker.call(GameWorker.java:16)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:750)
WARN  2024-10-17 20:51:24,425 FIX command was called for game adafb548-125f-4cba-8df2-97a233f23f05 by tiera3; players: tiera3 (play), xenohedron (play); !!!NOT GAME THREAD!!! Two Player Duel; T10.DB; active: xenohedron; stack: 0 =>[CALL - 1190] GameController.attemptToFixGame 

Probably unrelated, but we had multiple misfires when trying to launch this tournament in the first place.