Allow the potion effect caused by WitherSkulls to be cancelled along with damage cancellation (e.g. via events).

CraftBukkit-Patches/0117-Cancellable-WitherSkull-potion-effect.patch

@@ -0,0 +1,36 @@
+From 300acb214df362bccede10b67b02fd974f353ea4 Mon Sep 17 00:00:00 2001
+From: drXor <mcyoungsota@gmail.com>
+Date: Tue, 25 Feb 2014 15:15:26 -0400
+Subject: [PATCH] Cancellable WitherSkull potion effect
+
+
+diff --git a/src/main/java/net/minecraft/server/EntityWitherSkull.java b/src/main/java/net/minecraft/server/EntityWitherSkull.java
+index 2d428f9..de0f2bb 100644
+--- a/src/main/java/net/minecraft/server/EntityWitherSkull.java
++++ b/src/main/java/net/minecraft/server/EntityWitherSkull.java
+@@ -35,15 +35,19 @@ public class EntityWitherSkull extends EntityFireball {
+     protected void a(MovingObjectPosition movingobjectposition) {
+         if (!this.world.isStatic) {
+             if (movingobjectposition.entity != null) {
++                // Spigot start
++                boolean didDamage = false;         	
+                 if (this.shooter != null) {
+-                    if (movingobjectposition.entity.damageEntity(DamageSource.mobAttack(this.shooter), 8.0F) && !movingobjectposition.entity.isAlive()) {
++                    didDamage = movingobjectposition.entity.damageEntity(DamageSource.mobAttack(this.shooter), 8.0F);
++                    if (didDamage && !movingobjectposition.entity.isAlive()) {
+                         this.shooter.heal(5.0F, org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason.WITHER); // CraftBukkit
+                     }
+                 } else {
+-                    movingobjectposition.entity.damageEntity(DamageSource.MAGIC, 5.0F);
++                    didDamage = movingobjectposition.entity.damageEntity(DamageSource.MAGIC, 5.0F);
+                 }
+ 
+-                if (movingobjectposition.entity instanceof EntityLiving) {
++                if (didDamage && movingobjectposition.entity instanceof EntityLiving) {
++                // Spigot end
+                     byte b0 = 0;
+ 
+                     if (this.world.difficulty == EnumDifficulty.NORMAL) {
+-- 
+1.8.3.2
+