BaseSpawner.java.patch

--- a/net/minecraft/world/level/BaseSpawner.java
+++ b/net/minecraft/world/level/BaseSpawner.java
@@ -149,13 +_,15 @@
 
                         entity.moveTo(entity.getX(), entity.getY(), entity.getZ(), randomsource.nextFloat() * 360.0F, 0.0F);
                         if (entity instanceof Mob mob) {
-                            if (spawndata.getCustomSpawnRules().isEmpty() && !mob.checkSpawnRules(p_151312_, MobSpawnType.SPAWNER) || !mob.checkSpawnObstruction(p_151312_)) {
+                            if (!net.minecraftforge.event.ForgeEventFactory.checkSpawnPositionSpawner(mob, p_151312_, MobSpawnType.SPAWNER, spawndata, this)) {
                                 continue;
                             }
 
                             boolean flag1 = spawndata.getEntityToSpawn().size() == 1 && spawndata.getEntityToSpawn().contains("id", 8);
-                            if (flag1) {
-                                ((Mob)entity).finalizeSpawn(p_151312_, p_151312_.getCurrentDifficultyAt(entity.blockPosition()), MobSpawnType.SPAWNER, null);
+                            // Forge: Patch in FinalizeSpawn for spawners so it may be fired unconditionally, instead of only when vanilla normally would trigger it.
+                            var event = net.minecraftforge.event.ForgeEventFactory.onFinalizeSpawnSpawner(mob, p_151312_, p_151312_.getCurrentDifficultyAt(entity.blockPosition()), null, compoundtag, this);
+                            if (!event.isCanceled() && flag1) {
+                                ((Mob)entity).finalizeSpawn(p_151312_, event.getDifficulty(), MobSpawnType.SPAWNER, null);
                             }
 
                             spawndata.getEquipment().ifPresent(mob::equip);
@@ -305,5 +_,15 @@
 
     public double getoSpin() {
         return this.oSpin;
+    }
+
+    @Nullable
+    public Entity getSpawnerEntity() {
+       return null;
+    }
+
+    @Nullable
+    public net.minecraft.world.level.block.entity.BlockEntity getSpawnerBlockEntity() {
+        return null;
     }
 }