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
@@ -49,15 +49,17 @@
     public int maxNearbyEntities = 6;
     public int requiredPlayerRange = 16;
     public int spawnRange = 4;
+    private int tickDelay = 0; // Paper - Configurable mob spawner tick rate
 
     public BaseSpawner() {}
 
     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) {
-        return world.hasNearbyAlivePlayer((double) pos.getX() + 0.5D, (double) pos.getY() + 0.5D, (double) pos.getZ() + 0.5D, (double) this.requiredPlayerRange);
+        return world.hasNearbyAlivePlayerThatAffectsSpawning((double) pos.getX() + 0.5D, (double) pos.getY() + 0.5D, (double) pos.getZ() + 0.5D, (double) this.requiredPlayerRange); // Paper - Affects Spawning API
     }
 
     public void clientTick(Level world, BlockPos pos) {
@@ -82,13 +84,18 @@
     }
 
     public void serverTick(ServerLevel world, BlockPos pos) {
+        // Paper start - Configurable mob spawner tick rate
+        if (spawnDelay > 0 && --tickDelay > 0) return;
+        tickDelay = world.paperConfig().tickRates.mobSpawner;
+        if (tickDelay == -1) { return; } // If disabled
+        // Paper end - Configurable mob spawner tick rate
         if (this.isNearPlayer(world, pos)) {
-            if (this.spawnDelay == -1) {
+            if (this.spawnDelay < -tickDelay) { // Paper - Configurable mob spawner tick rate
                 this.delay(world, pos);
             }
 
             if (this.spawnDelay > 0) {
-                --this.spawnDelay;
+                this.spawnDelay -= tickDelay; // Paper - Configurable mob spawner tick rate
             } else {
                 boolean flag = false;
                 RandomSource randomsource = world.getRandom();
@@ -157,13 +164,26 @@
                                 ((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)) {
+                        entity.spawnedViaMobSpawner = true; // Paper
+                        flag = true; // Paper
+                        // 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;
                         }
@@ -174,7 +194,7 @@
                             ((Mob) entity).spawnAnim();
                         }
 
-                        flag = true;
+                        //flag = true; // Paper - moved up above cancellable event
                     }
                 }