PaperMC/nms-patches/EntityLargeFireball.patch

--- a/net/minecraft/server/EntityLargeFireball.java
+++ b/net/minecraft/server/EntityLargeFireball.java
@@ -1,15 +1,19 @@
 package net.minecraft.server;
 
+import org.bukkit.event.entity.ExplosionPrimeEvent; // CraftBukkit
+
 public class EntityLargeFireball extends EntityFireball {
 
     public int yield = 1;
 
     public EntityLargeFireball(World world) {
         super(EntityTypes.FIREBALL, world, 1.0F, 1.0F);
+        isIncendiary = this.world.getGameRules().getBoolean("mobGriefing"); // CraftBukkit
     }
 
     public EntityLargeFireball(World world, EntityLiving entityliving, double d0, double d1, double d2) {
         super(EntityTypes.FIREBALL, entityliving, d0, d1, d2, world, 1.0F, 1.0F);
+        isIncendiary = this.world.getGameRules().getBoolean("mobGriefing"); // CraftBukkit
     }
 
     protected void a(MovingObjectPosition movingobjectposition) {
@@ -21,7 +25,15 @@
 
             boolean flag = this.world.getGameRules().getBoolean("mobGriefing");
 
-            this.world.createExplosion((Entity) null, this.locX, this.locY, this.locZ, (float) this.yield, flag, flag);
+            // CraftBukkit start - fire ExplosionPrimeEvent
+            ExplosionPrimeEvent event = new ExplosionPrimeEvent((org.bukkit.entity.Explosive) org.bukkit.craftbukkit.entity.CraftEntity.getEntity(this.world.getServer(), this));
+            this.world.getServer().getPluginManager().callEvent(event);
+
+            if (!event.isCancelled()) {
+                // give 'this' instead of (Entity) null so we know what causes the damage
+                this.world.createExplosion(this, this.locX, this.locY, this.locZ, event.getRadius(), event.getFire(), isIncendiary);
+            }
+            // CraftBukkit end
             this.die();
         }
 
@@ -35,7 +47,8 @@
     public void a(NBTTagCompound nbttagcompound) {
         super.a(nbttagcompound);
         if (nbttagcompound.hasKeyOfType("ExplosionPower", 99)) {
-            this.yield = nbttagcompound.getInt("ExplosionPower");
+            // CraftBukkit - set bukkitYield when setting explosionpower
+            bukkitYield = this.yield = nbttagcompound.getInt("ExplosionPower");
         }
 
     }