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: Block entity 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 ec6640bc761b6232d6b48a32fae11e60d5cdcbdf..917ee31fedd92184d97f2c0a11fd61583361de92 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -721,6 +721,8 @@ 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 - Fix MC-117075; use removeAll
+        toRemove.add(null); // Paper - Fix MC-117075
         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);
@@ -729,12 +731,13 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
             if (tickingblockentity.isRemoved()) {
                 // Spigot start
                 tilesThisCycle--;
-                this.blockEntityTickers.remove(this.tileTickPosition--);
+                toRemove.add(tickingblockentity); // Paper - Fix MC-117075; use removeAll
                 // Spigot end
             } else if (flag && this.shouldTickBlocksAt(tickingblockentity.getPos())) {
                 tickingblockentity.tick();
             }
         }
+        this.blockEntityTickers.removeAll(toRemove); // Paper - Fix MC-117075
 
         this.timings.tileEntityTick.stopTiming(); // Spigot
         this.tickingBlockEntities = false;