CatServer/patches/net/minecraft/tileentity/MobSpawnerBaseLogic.java.patch

--- ../src-base/minecraft/net/minecraft/tileentity/MobSpawnerBaseLogic.java
+++ ../src-work/minecraft/net/minecraft/tileentity/MobSpawnerBaseLogic.java
@@ -22,21 +22,21 @@
 
 public abstract class MobSpawnerBaseLogic
 {
-    private int spawnDelay = 20;
+    public int spawnDelay = 20;
     private final List<WeightedSpawnerEntity> potentialSpawns = Lists.<WeightedSpawnerEntity>newArrayList();
     private WeightedSpawnerEntity spawnData = new WeightedSpawnerEntity();
     private double mobRotation;
     private double prevMobRotation;
-    private int minSpawnDelay = 200;
-    private int maxSpawnDelay = 800;
-    private int spawnCount = 4;
+    public int minSpawnDelay = 200;
+    public int maxSpawnDelay = 800;
+    public int spawnCount = 4;
     private Entity cachedEntity;
-    private int maxNearbyEntities = 6;
-    private int activatingRangeFromPlayer = 16;
-    private int spawnRange = 4;
+    public int maxNearbyEntities = 6;
+    public int activatingRangeFromPlayer = 16;
+    public int spawnRange = 4;
 
     @Nullable
-    private ResourceLocation getEntityId()
+    public ResourceLocation getEntityId()
     {
         String s = this.spawnData.getNbt().getString("id");
         return StringUtils.isNullOrEmpty(s) ? null : new ResourceLocation(s);
@@ -47,6 +47,7 @@
         if (id != null)
         {
             this.spawnData.getNbt().setString("id", id.toString());
+            this.potentialSpawns.clear(); // CraftBukkit - SPIGOT-3496, MC-92282
         }
     }
 
@@ -124,14 +125,18 @@
                     EntityLiving entityliving = entity instanceof EntityLiving ? (EntityLiving)entity : null;
                     entity.setLocationAndAngles(entity.posX, entity.posY, entity.posZ, world.rand.nextFloat() * 360.0F, 0.0F);
 
-                    if (entityliving == null || entityliving.getCanSpawnHere() && entityliving.isNotColliding())
+                    if (entityliving == null || net.minecraftforge.event.ForgeEventFactory.canEntitySpawnSpawner(entityliving, getSpawnerWorld(), (float)entity.posX, (float)entity.posY, (float)entity.posZ, this))
                     {
                         if (this.spawnData.getNbt().getSize() == 1 && this.spawnData.getNbt().hasKey("id", 8) && entity instanceof EntityLiving)
                         {
+                            if (!net.minecraftforge.event.ForgeEventFactory.doSpecialSpawn(entityliving, this.getSpawnerWorld(), (float)entity.posX, (float)entity.posY, (float)entity.posZ, this))
                             ((EntityLiving)entity).onInitialSpawn(world.getDifficultyForLocation(new BlockPos(entity)), (IEntityLivingData)null);
                         }
-
-                        AnvilChunkLoader.spawnEntity(entity, world);
+                        if (entity.world.spigotConfig.nerfSpawnerMobs) entity.fromMobSpawner = true; // Spigot Start
+                        if (org.bukkit.craftbukkit.event.CraftEventFactory.callSpawnerSpawnEvent(entity, blockpos).isCancelled()) {
+                            continue;
+                        }
+                        AnvilChunkLoader.spawnEntity(entity, world, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER);
                         world.playEvent(2004, blockpos, 0);
 
                         if (entityliving != null)
@@ -307,4 +312,7 @@
     {
         return this.prevMobRotation;
     }
+
+    /* ======================================== FORGE START =====================================*/
+    @Nullable public Entity getSpawnerEntity() { return null; }
 }