Paper/patches/server/1027-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 01c7b3623314bb0e6fa0a135de3db7c42ca5e373..e0dae41eb94da08649cba607975798dc2ac328ad 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1681,6 +1681,7 @@ 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
         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 47857a43753e86d1c7c535e69ed07b31d753ad99..b240dc6a1e45b534a017806b41ddb76423691ee7 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -713,7 +713,11 @@ 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 82695b6f25011a315027bd7a5cb305af31663d4a..d362a06d0600003d40f632eac602ff552cafb9da 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 03ca9ae4a195a6caacf2424e069a9644357e7e06..a42023793805b294dc167ec2cd5445f32b0c51eb 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 5a9f4a022c8e7a0804543335bfe91e1328d040e6..8094c133f9e934c98eee09738220bacd87a0a364 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 52c389472e013e658344496218689465350bf8a3..8c4d434bffa640a17d6870080f79cd0e492c7537 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) {