PaperMC/paper-server/patches/sources/net/minecraft/world/level/BaseSpawner.java.patch

--- a/net/minecraft/world/level/BaseSpawner.java
+++ b/net/minecraft/world/level/BaseSpawner.java
@@ -54,6 +54,7 @@
 
     public void setEntityId(EntityType<?> type, @Nullable Level world, RandomSource random, BlockPos pos) {
         this.getOrCreateNextSpawnData(world, random, pos).getEntityToSpawn().putString("id", BuiltInRegistries.ENTITY_TYPE.getKey(type).toString());
+        this.spawnPotentials = SimpleWeightedRandomList.empty(); // CraftBukkit - SPIGOT-3496, MC-92282
     }
 
     public boolean isNearPlayer(Level world, BlockPos pos) {
@@ -157,13 +158,24 @@
                                 ((Mob) entity).finalizeSpawn(world, world.getCurrentDifficultyAt(entity.blockPosition()), EntitySpawnReason.SPAWNER, (SpawnGroupData) null);
                             }
 
-                            Optional optional1 = mobspawnerdata.getEquipment();
+                            Optional<net.minecraft.world.entity.EquipmentTable> optional1 = mobspawnerdata.getEquipment(); // CraftBukkit - decompile error
 
                             Objects.requireNonNull(entityinsentient);
                             optional1.ifPresent(entityinsentient::equip);
+                            // Spigot Start
+                            if ( entityinsentient.level().spigotConfig.nerfSpawnerMobs )
+                            {
+                                entityinsentient.aware = false;
+                            }
+                            // Spigot End
                         }
 
-                        if (!world.tryAddFreshEntityWithPassengers(entity)) {
+                        // CraftBukkit start
+                        if (org.bukkit.craftbukkit.event.CraftEventFactory.callSpawnerSpawnEvent(entity, pos).isCancelled()) {
+                            continue;
+                        }
+                        if (!world.tryAddFreshEntityWithPassengers(entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER)) {
+                            // CraftBukkit end
                             this.delay(world, pos);
                             return;
                         }