1 files changed, 78 insertions, 0 deletions
diff --git a/patches/server/0816-Throw-exception-on-world-create-while-being-ticked.patch b/patches/server/0816-Throw-exception-on-world-create-while-being-ticked.patch
new file mode 100644
index 0000000000..cdc81374d4
--- /dev/null
+++ b/patches/server/0816-Throw-exception-on-world-create-while-being-ticked.patch
@@ -0,0 +1,78 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <[email protected]>
+Date: Tue, 22 Mar 2022 12:44:30 -0700
+Subject: [PATCH] Throw exception on world create while being ticked
+
+There are no plans to support creating worlds while worlds are
+being ticked themselvess.
+
+diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
+index 18041f137157ca95639c0511f225bbb58356fe2b..47c984495a66fdbb10dea6bab33da78f4ab70a38 100644
+--- a/src/main/java/net/minecraft/server/MinecraftServer.java
++++ b/src/main/java/net/minecraft/server/MinecraftServer.java
+@@ -304,6 +304,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+ 
+     public volatile Thread shutdownThread; // Paper
+     public volatile boolean abnormalExit = false; // Paper
++    public boolean isIteratingOverLevels = false; // Paper
+ 
+     public static <S extends MinecraftServer> S spin(Function<Thread, S> serverFactory) {
+         AtomicReference<S> atomicreference = new AtomicReference();
+@@ -1470,7 +1471,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+         this.getFunctions().tick();
+         MinecraftTimings.commandFunctionsTimer.stopTiming(); // Spigot // Paper
+         this.profiler.popPush("levels");
+-        Iterator iterator = this.getAllLevels().iterator();
++        //Iterator iterator = this.getAllLevels().iterator(); // Paper - moved down
+ 
+         // CraftBukkit start
+         // Run tasks that are waiting on processing
+@@ -1502,6 +1503,8 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+         // Paper end
+         MinecraftTimings.timeUpdateTimer.stopTiming(); // Spigot // Paper
+ 
++        this.isIteratingOverLevels = true; // Paper
++        Iterator iterator = this.getAllLevels().iterator(); // Paper - move down
+         while (iterator.hasNext()) {
+             ServerLevel worldserver = (ServerLevel) iterator.next();
+             worldserver.hasPhysicsEvent =  org.bukkit.event.block.BlockPhysicsEvent.getHandlerList().getRegisteredListeners().length > 0; // Paper
+@@ -1548,6 +1551,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+             this.profiler.pop();
+             worldserver.explosionDensityCache.clear(); // Paper - Optimize explosions
+         }
++        this.isIteratingOverLevels = false; // Paper
+ 
+         this.profiler.popPush("connection");
+         MinecraftTimings.connectionTimer.startTiming(); // Spigot
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+index 1665d99aa45f708939dfc21d17a7b02182c7aefb..c1229e3ce355fb324a0fe0c37b4d39fbdc60c7a3 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+@@ -876,6 +876,11 @@ public final class CraftServer implements Server {
+         return new ArrayList<World>(this.worlds.values());
+     }
+ 
++    @Override
++    public boolean isTickingWorlds() {
++        return console.isIteratingOverLevels;
++    }
++
+     public DedicatedPlayerList getHandle() {
+         return this.playerList;
+     }
+@@ -1135,6 +1140,7 @@ public final class CraftServer implements Server {
+     @Override
+     public World createWorld(WorldCreator creator) {
+         Preconditions.checkState(this.console.getAllLevels().iterator().hasNext(), "Cannot create additional worlds on STARTUP");
++        //Preconditions.checkState(!this.console.isIteratingOverLevels, "Cannot create a world while worlds are being ticked"); // Paper - Cat - Temp disable. We'll see how this goes.
+         Preconditions.checkArgument(creator != null, "WorldCreator cannot be null");
+ 
+         String name = creator.name();
+@@ -1275,6 +1281,7 @@ public final class CraftServer implements Server {
+ 
+     @Override
+     public boolean unloadWorld(World world, boolean save) {
++        //Preconditions.checkState(!this.console.isIteratingOverLevels, "Cannot unload a world while worlds are being ticked"); // Paper - Cat - Temp disable. We'll see how this goes.
+         if (world == null) {
+             return false;
+         }