Paper/patches/server/0899-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 7cecbac43f1cd2d9516034ea9d2633c0c76e61f4..7a985c30a973efacf3e8b70e7163c550d86b0870 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1189,6 +1189,7 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
     // 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 4cd07d9a90885b59ef1b2be7562386d5e8c7b2ae..7657888bab53428fda9d3d10ac35bfddc5c16266 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -632,7 +632,11 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         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 64dc0bd1900575e40ac72a98c6df371223bd244c..c2693d530be00af16b2aa4ca4afd1d136db68183 100644
--- a/src/main/java/net/minecraft/world/entity/EntityType.java
+++ b/src/main/java/net/minecraft/world/entity/EntityType.java
@@ -649,9 +649,15 @@ public class EntityType<T extends Entity> implements FeatureElement, EntityTypeT
     }
 
     public static Optional<Entity> create(CompoundTag nbt, Level world, EntitySpawnReason reason) {
+    // Paper start - Don't fire sync event during generation
+        return create(nbt, world, reason, false);
+    }
+    public static Optional<Entity> create(CompoundTag nbt, Level world, EntitySpawnReason reason, boolean generation) {
+    // Paper end - Don't fire sync event during generation
         return Util.ifElse(EntityType.by(nbt).map((entitytypes) -> {
             return entitytypes.create(world, reason);
         }), (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 2bff94cef4fef66b81508a2ef4b5613e76044832..22c565fd6b14ae018f4526b174388ed5247600f6 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -1159,6 +1159,11 @@ 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));
@@ -1178,10 +1183,13 @@ 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) {
@@ -1190,7 +1198,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
                 flag = true;
                 mobeffect.onEffectAdded(this);
                 // 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 6c2d4c2163cf299c0943af21d4dc367b5677c089..72e42605c278028480c368762da18f61806d766a 100644
--- a/src/main/java/net/minecraft/world/entity/monster/Spider.java
+++ b/src/main/java/net/minecraft/world/entity/monster/Spider.java
@@ -172,7 +172,7 @@ public class Spider extends Monster {
             Holder<MobEffect> holder = entityspider_groupdataspider.effect;
 
             if (holder != null) {
-                this.addEffect(new MobEffectInstance(holder, -1), org.bukkit.event.entity.EntityPotionEffectEvent.Cause.SPIDER_SPAWN); // CraftBukkit
+                this.addEffect(new MobEffectInstance(holder, -1), null, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.SPIDER_SPAWN, world instanceof net.minecraft.server.level.ServerLevel); // CraftBukkit
             }
         }
 
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 734f511d197bc6bf2b02588069eb02c0224781f5..d35b731751e851bee531aa5e7996557658ba6fae 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
@@ -549,7 +549,7 @@ public class StructureTemplate {
     private static Optional<Entity> createEntityIgnoreException(ServerLevelAccessor world, CompoundTag nbt) {
         // CraftBukkit start
         // try {
-            return EntityType.create(nbt, world.getLevel(), EntitySpawnReason.STRUCTURE);
+            return EntityType.create(nbt, world.getLevel(), EntitySpawnReason.STRUCTURE, 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 e444662ee4d9405eeea7caa41b9cd6b36586d840..54c4434662d057a08800918641b95708cda61207 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/DelegatedGeneratorAccess.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/DelegatedGeneratorAccess.java
@@ -90,15 +90,17 @@ public abstract class DelegatedGeneratorAccess implements WorldGenLevel {
         return this.handle.getLevel();
     }
 
-    @Override
-    public void addFreshEntityWithPassengers(Entity entity) {
-        this.handle.addFreshEntityWithPassengers(entity);
-    }
-
-    @Override
-    public void addFreshEntityWithPassengers(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
-        this.handle.addFreshEntityWithPassengers(entity, reason);
-    }
+    // 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) {
+    //     this.handle.addFreshEntityWithPassengers(entity);
+    // }
+    //
+    // @Override
+    // public void addFreshEntityWithPassengers(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
+    //     this.handle.addFreshEntityWithPassengers(entity, reason);
+    // }
+    // Paper end - Don't fire sync event during generation; don't override these methods so all entities are run through addFreshEntity
 
     @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 35ecf6f824aca56a20280dd683123df1d0c7d66e..1d1fdcf10498c421f106158254e052da6d68d8a5 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) {