From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 24 Mar 2019 00:24:52 -0400
Subject: [PATCH] Entity#getEntitySpawnReason

Allows you to return the SpawnReason for why an Entity Spawned

Pre existing entities will return NATURAL if it was a non
persistenting Living Entity, SPAWNER for spawners,
or DEFAULT since data was not stored.

diff --git a/src/main/java/net/minecraft/server/commands/SummonCommand.java b/src/main/java/net/minecraft/server/commands/SummonCommand.java
index bf72cf288ade52ee8cc41ca978f368b3ad575951..798999be50d26be357ef3c6d5b9383ce4d1048c1 100644
--- a/src/main/java/net/minecraft/server/commands/SummonCommand.java
+++ b/src/main/java/net/minecraft/server/commands/SummonCommand.java
@@ -57,6 +57,7 @@ public class SummonCommand {
             ServerLevel worldserver = source.getLevel();
             Entity entity = EntityType.loadEntityRecursive(nbttagcompound1, worldserver, (entity1) -> {
                 entity1.moveTo(pos.x, pos.y, pos.z, entity1.getYRot(), entity1.getXRot());
+                entity1.spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.COMMAND; // Paper - Entity#getEntitySpawnReason
                 return entity1;
             });
 
diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index b151506b96a51c74ba408cb555a4d38507b2f8c1..bbcee9d8dbf17085b11bb5e38eb37271c51219ba 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -1207,6 +1207,7 @@ public class ServerLevel extends Level implements WorldGenLevel {
             return true;
         }
         // Paper end - extra debug info
+        if (entity.spawnReason == null) entity.spawnReason = spawnReason; // Paper - Entity#getEntitySpawnReason
         if (entity.isRemoved()) {
             // WorldServer.LOGGER.warn("Tried to add entity {} but it was marked as removed already", EntityTypes.getKey(entity.getType())); // CraftBukkit
             return false;
diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
index 00c43d7b846e97e2cc2105c93be5ce918fafd775..8f90e8cd36348089799097807ead774e186c2604 100644
--- a/src/main/java/net/minecraft/server/players/PlayerList.java
+++ b/src/main/java/net/minecraft/server/players/PlayerList.java
@@ -223,6 +223,11 @@ public abstract class PlayerList {
             worldserver1 = worldserver;
         }
 
+        // Paper start - Entity#getEntitySpawnReason
+        if (optional.isEmpty()) {
+            player.spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT; // set Player SpawnReason to DEFAULT on first login
+        }
+        // Paper end - Entity#getEntitySpawnReason
         player.setServerLevel(worldserver1);
         String s1 = connection.getLoggableAddress(this.server.logIPs());
 
@@ -348,7 +353,7 @@ public abstract class PlayerList {
             CompoundTag nbttagcompound = ((CompoundTag) optional.get()).getCompound("RootVehicle");
             ServerLevel finalWorldServer = worldserver1; // CraftBukkit - decompile error
             Entity entity = EntityType.loadEntityRecursive(nbttagcompound.getCompound("Entity"), worldserver1, (entity1) -> {
-                return !finalWorldServer.addWithUUID(entity1) ? null : entity1; // CraftBukkit - decompile error
+                return !finalWorldServer.addWithUUID(entity1, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.MOUNT) ? null : entity1; // CraftBukkit - decompile error // Paper - Entity#getEntitySpawnReason
             });
 
             if (entity != null) {
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 5b3de422b07f680e6639ee84f076bffb3c901d0e..631f2d70b5fd6dabc06062e3c77802d2b61398ae 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -247,6 +247,7 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
         }
     }
     // Paper end - Share random for entities to make them more random
+    public org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason spawnReason; // Paper - Entity#getEntitySpawnReason
 
     private CraftEntity bukkitEntity;
 
@@ -2276,6 +2277,9 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
                 }
                 nbttagcompound.put("Paper.Origin", this.newDoubleList(origin.getX(), origin.getY(), origin.getZ()));
             }
+            if (spawnReason != null) {
+                nbttagcompound.putString("Paper.SpawnReason", spawnReason.name());
+            }
             // Save entity's from mob spawner status
             if (spawnedViaMobSpawner) {
                 nbttagcompound.putBoolean("Paper.FromMobSpawner", true);
@@ -2422,6 +2426,26 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
             }
 
             spawnedViaMobSpawner = nbt.getBoolean("Paper.FromMobSpawner"); // Restore entity's from mob spawner status
+            if (nbt.contains("Paper.SpawnReason")) {
+                String spawnReasonName = nbt.getString("Paper.SpawnReason");
+                try {
+                    spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.valueOf(spawnReasonName);
+                } catch (Exception ignored) {
+                    LOGGER.error("Unknown SpawnReason " + spawnReasonName + " for " + this);
+                }
+            }
+            if (spawnReason == null) {
+                if (spawnedViaMobSpawner) {
+                    spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER;
+                } else if (this instanceof Mob && (this instanceof net.minecraft.world.entity.animal.Animal || this instanceof net.minecraft.world.entity.animal.AbstractFish) && !((Mob) this).removeWhenFarAway(0.0)) {
+                    if (!nbt.getBoolean("PersistenceRequired")) {
+                        spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.NATURAL;
+                    }
+                }
+            }
+            if (spawnReason == null) {
+                spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT;
+            }
             // Paper end
 
         } catch (Throwable throwable) {
diff --git a/src/main/java/net/minecraft/world/level/BaseSpawner.java b/src/main/java/net/minecraft/world/level/BaseSpawner.java
index ee897b8c9462dbb3d7be9a2994753155065ce205..1d0964a7f544735a0213d5c7832c71f53db139a9 100644
--- a/src/main/java/net/minecraft/world/level/BaseSpawner.java
+++ b/src/main/java/net/minecraft/world/level/BaseSpawner.java
@@ -191,6 +191,7 @@ public abstract class BaseSpawner {
                         }
 
                         entity.spawnedViaMobSpawner = true; // Paper
+                        entity.spawnReason = org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER; // Paper - Entity#getEntitySpawnReason
                         flag = true; // Paper
                         // CraftBukkit start
                         if (org.bukkit.craftbukkit.event.CraftEventFactory.callSpawnerSpawnEvent(entity, pos).isCancelled()) {
diff --git a/src/main/java/net/minecraft/world/level/block/entity/SculkShriekerBlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/SculkShriekerBlockEntity.java
index dbc0b69603dcffbf3d41d79719aa0f2b7da4a131..dd86f5ec5b2051aeea4e19ff97146362b1e8d019 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/SculkShriekerBlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/SculkShriekerBlockEntity.java
@@ -189,7 +189,7 @@ public class SculkShriekerBlockEntity extends BlockEntity implements GameEventLi
 
     private boolean trySummonWarden(ServerLevel world) {
         return this.warningLevel >= 4
-            && SpawnUtil.trySpawnMob(EntityType.WARDEN, MobSpawnType.TRIGGERED, world, this.getBlockPos(), 20, 5, 6, SpawnUtil.Strategy.ON_TOP_OF_COLLIDER)
+            && SpawnUtil.trySpawnMob(EntityType.WARDEN, MobSpawnType.TRIGGERED, world, this.getBlockPos(), 20, 5, 6, SpawnUtil.Strategy.ON_TOP_OF_COLLIDER, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.NATURAL, null) // Paper - Entity#getEntitySpawnReason
                 .isPresent();
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index bddf98bdf60473eb1d2e533cf533ed7eee797aaa..ce70c8fddbe63d0af2b1f988ce9a2b40c5d48066 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -1018,4 +1018,11 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         return this.getHandle().spawnedViaMobSpawner;
     }
     // Paper end - Entity#fromMobSpawner
+
+    // Paper start - entity spawn reason API
+    @Override
+    public org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason getEntitySpawnReason() {
+        return getHandle().spawnReason;
+    }
+    // Paper end - entity spawn reason API
 }
