From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: mezz <tehgeek@gmail.com>
Date: Wed, 9 Aug 2017 17:51:22 -0500
Subject: [PATCH] Fix MC-117075: TE Unload Lag Spike


diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index c6e56303ec8ee466a6de7e6bd76c4f6814e8db30..2dad35f00a98be534db1da1a38a6865e41a1a94d 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -816,6 +816,8 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
         boolean flag = this.tickRateManager().runsNormally();
 
         int tilesThisCycle = 0;
+        var toRemove = new it.unimi.dsi.fastutil.objects.ReferenceOpenHashSet<TickingBlockEntity>(); // Paper - use removeAll
+        toRemove.add(null);
         for (tileTickPosition = 0; tileTickPosition < this.blockEntityTickers.size(); tileTickPosition++) { // Paper - Disable tick limiters
             this.tileTickPosition = (this.tileTickPosition < this.blockEntityTickers.size()) ? this.tileTickPosition : 0;
             TickingBlockEntity tickingblockentity = (TickingBlockEntity) this.blockEntityTickers.get(this.tileTickPosition);
@@ -823,7 +825,6 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
             if (tickingblockentity == null) {
                 this.getCraftServer().getLogger().severe("Spigot has detected a null entity and has removed it, preventing a crash");
                 tilesThisCycle--;
-                this.blockEntityTickers.remove(this.tileTickPosition--);
                 continue;
             }
             // Spigot end
@@ -831,12 +832,13 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
             if (tickingblockentity.isRemoved()) {
                 // Spigot start
                 tilesThisCycle--;
-                this.blockEntityTickers.remove(this.tileTickPosition--);
+                toRemove.add(tickingblockentity); // Paper - use removeAll
                 // Spigot end
             } else if (flag && this.shouldTickBlocksAt(tickingblockentity.getPos())) {
                 tickingblockentity.tick();
             }
         }
+        this.blockEntityTickers.removeAll(toRemove);
 
         this.timings.tileEntityTick.stopTiming(); // Spigot
         this.tickingBlockEntities = false;