PaperMC/patches/server/1021-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 8680f351795eb50b8eff231cde4a28dd2f8aa509..48b0bce01a9ae1ce869203a685be308d49a8c880 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1676,6 +1676,7 @@ 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 be36e4307636a02c806ed8eb9d217e84d837fef2..4fdc55b78c4212603bd57a292c72d89c73d28871 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -712,7 +712,11 @@ 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 dd4cf9011bf48623e95d5d0f3ff27ee962c88200..a039217f9293ad3b0cc74c49450472eb44c6a139 100644
--- a/src/main/java/net/minecraft/world/entity/EntityType.java
+++ b/src/main/java/net/minecraft/world/entity/EntityType.java
@@ -588,9 +588,15 @@ 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 4785c1029f6c68406d6405ed5e950a75230dfdc0..68e1ef67e58ef348d35dfc3b3e890336d4cb2108 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -1134,6 +1134,11 @@ 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));
@@ -1153,10 +1158,13 @@ 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) {
@@ -1164,7 +1172,7 @@ 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 ff004d5c0dee027acea51aa4886065636335e2a9..0c68ed759421d6bce4435399f1b4980510081cac 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 a650411e3fa7e2a045ac55502c77028be348acf1..86a20c91beff6b27e6ec886e49ba902b216106f2 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) {