From 0caecf68db6fc68462d1d62af09857c1a25e9495 Mon Sep 17 00:00:00 2001
From: Camotoy <20743703+DoctorMacc@users.noreply.github.com>
Date: Sun, 26 Apr 2020 00:54:42 -0400
Subject: [PATCH] Only add entity to entity cache if ID doesn't exist (#428)

---
 .../network/session/cache/EntityCache.java       | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/connector/src/main/java/org/geysermc/connector/network/session/cache/EntityCache.java b/connector/src/main/java/org/geysermc/connector/network/session/cache/EntityCache.java
index f0b394fd..80d10b1a 100644
--- a/connector/src/main/java/org/geysermc/connector/network/session/cache/EntityCache.java
+++ b/connector/src/main/java/org/geysermc/connector/network/session/cache/EntityCache.java
@@ -58,13 +58,19 @@ public class EntityCache {
     }
 
     public void spawnEntity(Entity entity) {
-        cacheEntity(entity);
-        entity.spawnEntity(session);
+        if (cacheEntity(entity)) {
+            entity.spawnEntity(session);
+        }
     }
 
-    public void cacheEntity(Entity entity) {
-        entityIdTranslations.put(entity.getEntityId(), entity.getGeyserId());
-        entities.put(entity.getGeyserId(), entity);
+    public boolean cacheEntity(Entity entity) {
+        // Check to see if the entity exists, otherwise we can end up with duplicated mobs
+        if (!entityIdTranslations.containsKey(entity.getEntityId())) {
+            entityIdTranslations.put(entity.getEntityId(), entity.getGeyserId());
+            entities.put(entity.getGeyserId(), entity);
+            return true;
+        }
+        return false;
     }
 
     public boolean removeEntity(Entity entity, boolean force) {