PaperMC/paper-server/nms-patches/net/minecraft/world/entity/projectile/EntityLargeFireball.patch

--- a/net/minecraft/world/entity/projectile/EntityLargeFireball.java
+++ b/net/minecraft/world/entity/projectile/EntityLargeFireball.java
@@ -11,17 +11,21 @@
 import net.minecraft.world.phys.MovingObjectPosition;
 import net.minecraft.world.phys.MovingObjectPositionEntity;
 
+import org.bukkit.event.entity.ExplosionPrimeEvent; // CraftBukkit
+
 public class EntityLargeFireball extends EntityFireballFireball {
 
     public int explosionPower = 1;
 
     public EntityLargeFireball(EntityTypes<? extends EntityLargeFireball> entitytypes, World world) {
         super(entitytypes, world);
+        isIncendiary = this.level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING); // CraftBukkit
     }
 
     public EntityLargeFireball(World world, EntityLiving entityliving, double d0, double d1, double d2, int i) {
         super(EntityTypes.FIREBALL, entityliving, d0, d1, d2, world);
         this.explosionPower = i;
+        isIncendiary = this.level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING); // CraftBukkit
     }
 
     @Override
@@ -30,7 +34,15 @@
         if (!this.level.isClientSide) {
             boolean flag = this.level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING);
 
-            this.level.explode((Entity) null, this.getX(), this.getY(), this.getZ(), (float) this.explosionPower, flag, flag ? Explosion.Effect.DESTROY : Explosion.Effect.NONE);
+            // CraftBukkit start - fire ExplosionPrimeEvent
+            ExplosionPrimeEvent event = new ExplosionPrimeEvent((org.bukkit.entity.Explosive) this.getBukkitEntity());
+            this.level.getCraftServer().getPluginManager().callEvent(event);
+
+            if (!event.isCancelled()) {
+                // give 'this' instead of (Entity) null so we know what causes the damage
+                this.level.explode(this, this.getX(), this.getY(), this.getZ(), event.getRadius(), event.getFire(), flag ? Explosion.Effect.DESTROY : Explosion.Effect.NONE);
+            }
+            // CraftBukkit end
             this.discard();
         }
 
@@ -61,7 +73,8 @@
     public void readAdditionalSaveData(NBTTagCompound nbttagcompound) {
         super.readAdditionalSaveData(nbttagcompound);
         if (nbttagcompound.contains("ExplosionPower", 99)) {
-            this.explosionPower = nbttagcompound.getByte("ExplosionPower");
+            // CraftBukkit - set bukkitYield when setting explosionpower
+            bukkitYield = this.explosionPower = nbttagcompound.getByte("ExplosionPower");
         }
 
     }