Paper/patches/server/0965-Don-t-fire-sync-events-during-worldgen.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jake Potrebic <jake.m.potrebic@gmail.com>
Date: Thu, 23 Nov 2023 10:33:25 -0800
Subject: [PATCH] Don't fire sync events during worldgen

Fixes EntityPotionEffectEvent
Fixes EntityPoseChangeEvent

Asynchronous chunk generation provides an opportunity for things
to happen async that previously fired synchronous-only events. This
patch is for mitigating those issues by various methods.

Also fixes correctly marking/clearing the entity generation flag.
This patch sets the generation flag anytime an entity is created
via StructureTemplate before loading from NBT to catch uses of
the flag during the loading logic. This patch clears the generation
flag from an entity when added to a ServerLevel for the situation
where generation happened directly to a ServerLevel and the
entity still has the flag set.

diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 8235dace0f4a1090dfbd403db34231ccafe5f30e..9816913ad729fd39c173364b92e5db06a733bc55 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1220,6 +1220,7 @@ public class ServerLevel extends Level implements WorldGenLevel {
     // CraftBukkit start
     private boolean addEntity(Entity entity, CreatureSpawnEvent.SpawnReason spawnReason) {
         org.spigotmc.AsyncCatcher.catchOp("entity add"); // Spigot
+        entity.generation = false; // Paper - Don't fire sync event during generation; Reset flag if it was added during a ServerLevel generation process
         // Paper start - extra debug info
         if (entity.valid) {
             MinecraftServer.LOGGER.error("Attempted Double World add on {}", entity, new Throwable());
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 919c9ff3dd97d4bd2d41631176f9671f1987ad91..1de77621f159608f572ab4935ceb78863bb82c59 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -637,7 +637,11 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, S
         if (pose == this.getPose()) {
             return;
         }
-        this.level.getCraftServer().getPluginManager().callEvent(new EntityPoseChangeEvent(this.getBukkitEntity(), Pose.values()[pose.ordinal()]));
+        // Paper start - Don't fire sync event during generation
+        if (!this.generation) {
+            this.level.getCraftServer().getPluginManager().callEvent(new EntityPoseChangeEvent(this.getBukkitEntity(), Pose.values()[pose.ordinal()]));
+        }
+        // Paper end - Don't fire sync event during generation
         // CraftBukkit end
         this.entityData.set(Entity.DATA_POSE, pose);
     }
diff --git a/src/main/java/net/minecraft/world/entity/EntityType.java b/src/main/java/net/minecraft/world/entity/EntityType.java
index 656c68b37bc25d6b77f295f9efe0a81dd20b69c1..8ba573bb4099ee5b27b61f333e72d794c48d5f29 100644
--- a/src/main/java/net/minecraft/world/entity/EntityType.java
+++ b/src/main/java/net/minecraft/world/entity/EntityType.java
@@ -584,9 +584,15 @@ public class EntityType<T extends Entity> implements FeatureElement, EntityTypeT
     }
 
     public static Optional<Entity> create(CompoundTag nbt, Level world) {
+        // Paper start - Don't fire sync event during generation
+        return create(nbt, world, false);
+    }
+    public static Optional<Entity> create(CompoundTag nbt, Level world, boolean generation) {
+        // Paper end - Don't fire sync event during generation
         return Util.ifElse(EntityType.by(nbt).map((entitytypes) -> {
             return entitytypes.create(world);
         }), (entity) -> {
+            if (generation) entity.generation = true; // Paper - Don't fire sync event during generation
             entity.load(nbt);
         }, () -> {
             EntityType.LOGGER.warn("Skipping Entity with id {}", nbt.getString("id"));
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index d4fb052996d05668f1749d19b91e27044166f819..bdae6ea5528164995d9a256be6a2f9d0cb15d8ff 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -1142,6 +1142,11 @@ public abstract class LivingEntity extends Entity implements Attackable {
     }
 
     public boolean addEffect(MobEffectInstance mobeffect, @Nullable Entity entity, EntityPotionEffectEvent.Cause cause) {
+        // Paper start - Don't fire sync event during generation
+        return this.addEffect(mobeffect, entity, cause, true);
+    }
+    public boolean addEffect(MobEffectInstance mobeffect, @Nullable Entity entity, EntityPotionEffectEvent.Cause cause, boolean fireEvent) {
+        // Paper end - Don't fire sync event during generation
         // org.spigotmc.AsyncCatcher.catchOp("effect add"); // Spigot // Paper - move to API
         if (this.isTickingEffects) {
             this.effectsToProcess.add(new ProcessableEffect(mobeffect, cause));
@@ -1161,10 +1166,13 @@ public abstract class LivingEntity extends Entity implements Attackable {
                 override = new MobEffectInstance(mobeffect1).update(mobeffect);
             }
 
+            if (fireEvent) { // Paper - Don't fire sync event during generation
             EntityPotionEffectEvent event = CraftEventFactory.callEntityPotionEffectChangeEvent(this, mobeffect1, mobeffect, cause, override);
+            override = event.isOverride(); // Paper - Don't fire sync event during generation
             if (event.isCancelled()) {
                 return false;
             }
+            } // Paper - Don't fire sync event during generation
             // CraftBukkit end
 
             if (mobeffect1 == null) {
@@ -1172,7 +1180,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
                 this.onEffectAdded(mobeffect, entity);
                 flag = true;
                 // CraftBukkit start
-            } else if (event.isOverride()) {
+            } else if (override) { // Paper - Don't fire sync event during generation
                 mobeffect1.update(mobeffect);
                 this.onEffectUpdated(mobeffect1, true, entity);
                 // CraftBukkit end
diff --git a/src/main/java/net/minecraft/world/entity/monster/Spider.java b/src/main/java/net/minecraft/world/entity/monster/Spider.java
index d90da2f9e4d6214577bc81bd6c70ba8593788898..ffa4f34d964fbcc53e2dfe11677832db21a6eb93 100644
--- a/src/main/java/net/minecraft/world/entity/monster/Spider.java
+++ b/src/main/java/net/minecraft/world/entity/monster/Spider.java
@@ -182,7 +182,7 @@ public class Spider extends Monster {
             MobEffect mobeffectlist = entityspider_groupdataspider.effect;
 
             if (mobeffectlist != null) {
-                this.addEffect(new MobEffectInstance(mobeffectlist, -1), org.bukkit.event.entity.EntityPotionEffectEvent.Cause.SPIDER_SPAWN); // CraftBukkit
+                this.addEffect(new MobEffectInstance(mobeffectlist, -1), null, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.SPIDER_SPAWN, world instanceof net.minecraft.server.level.ServerLevel); // CraftBukkit // Paper - Don't fire sync event during generation; only if this is happening in a ServerLevel
             }
         }
 
diff --git a/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java b/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java
index ae8a42261337bf736d0cc1bbe18da2b773417ca4..471e8493622c89d44a82f42f135cb308c9e0fbfe 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/structure/templatesystem/StructureTemplate.java
@@ -518,7 +518,7 @@ public class StructureTemplate {
     private static Optional<Entity> createEntityIgnoreException(ServerLevelAccessor world, CompoundTag nbt) {
         // CraftBukkit start
         // try {
-            return EntityType.create(nbt, world.getLevel());
+            return EntityType.create(nbt, world.getLevel(), true); // Paper - Don't fire sync event during generation
         // } catch (Exception exception) {
             // return Optional.empty();
         // }
diff --git a/src/main/java/org/bukkit/craftbukkit/util/DelegatedGeneratorAccess.java b/src/main/java/org/bukkit/craftbukkit/util/DelegatedGeneratorAccess.java
index e37c2d82ed606cbfe00c152b08c3ab99ac751f69..7ed861cd67889e525ab4987c0afed245aca08833 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/DelegatedGeneratorAccess.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/DelegatedGeneratorAccess.java
@@ -93,15 +93,17 @@ public abstract class DelegatedGeneratorAccess implements WorldGenLevel {
         return this.handle.getLevel();
     }
 
-    @Override
-    public void addFreshEntityWithPassengers(Entity arg0, CreatureSpawnEvent.SpawnReason arg1) {
-        this.handle.addFreshEntityWithPassengers(arg0, arg1);
-    }
-
-    @Override
-    public void addFreshEntityWithPassengers(Entity entity) {
-        this.handle.addFreshEntityWithPassengers(entity);
-    }
+    // Paper start - Don't fire sync event during generation; don't override these methods so all entities are run through addFreshEntity
+    // @Override
+    // public void addFreshEntityWithPassengers(Entity arg0, CreatureSpawnEvent.SpawnReason arg1) {
+    //     this.handle.addFreshEntityWithPassengers(arg0, arg1);
+    // }
+    //
+    // @Override
+    // public void addFreshEntityWithPassengers(Entity entity) {
+    //     this.handle.addFreshEntityWithPassengers(entity);
+    // }
+    // Paper end - Don't fire sync event during generation; don't override these methods
 
     @Override
     public ServerLevel getMinecraftWorld() {
diff --git a/src/main/java/org/bukkit/craftbukkit/util/TransformerGeneratorAccess.java b/src/main/java/org/bukkit/craftbukkit/util/TransformerGeneratorAccess.java
index b4b297945fb601701aac845d09e88fb74b09c3fa..7482dfe64458320d44089c0778591694202e9f70 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/TransformerGeneratorAccess.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/TransformerGeneratorAccess.java
@@ -39,21 +39,23 @@ public class TransformerGeneratorAccess extends DelegatedGeneratorAccess {
         return super.addFreshEntity(arg0, arg1);
     }
 
-    @Override
-    public void addFreshEntityWithPassengers(Entity entity) {
-        if (this.structureTransformer != null && !this.structureTransformer.transformEntity(entity)) {
-            return;
-        }
-        super.addFreshEntityWithPassengers(entity);
-    }
-
-    @Override
-    public void addFreshEntityWithPassengers(Entity arg0, SpawnReason arg1) {
-        if (this.structureTransformer != null && !this.structureTransformer.transformEntity(arg0)) {
-            return;
-        }
-        super.addFreshEntityWithPassengers(arg0, arg1);
-    }
+    // Paper start - Don't fire sync event during generation; don't override these methods so all entities are run through addFreshEntity
+    // @Override
+    // public void addFreshEntityWithPassengers(Entity entity) {
+    //     if (this.structureTransformer != null && !this.structureTransformer.transformEntity(entity)) {
+    //         return;
+    //     }
+    //     super.addFreshEntityWithPassengers(entity);
+    // }
+    //
+    // @Override
+    // public void addFreshEntityWithPassengers(Entity arg0, SpawnReason arg1) {
+    //     if (this.structureTransformer != null && !this.structureTransformer.transformEntity(arg0)) {
+    //         return;
+    //     }
+    //     super.addFreshEntityWithPassengers(arg0, arg1);
+    // }
+    // Paper end - Don't fire sync event during generation; don't override these methods
 
     public boolean setCraftBlock(BlockPos position, CraftBlockState craftBlockState, int i, int j) {
         if (this.structureTransformer != null) {