SPIGOT-3417: Event for shearing snowman

nms-patches/EntitySnowman.patch

@@ -1,18 +1,17 @@
 --- a/net/minecraft/server/EntitySnowman.java
 +++ b/net/minecraft/server/EntitySnowman.java
-@@ -1,6 +1,11 @@
+@@ -1,6 +1,10 @@
  package net.minecraft.server;
  
  import javax.annotation.Nullable;
 +// CraftBukkit start
 +import org.bukkit.craftbukkit.event.CraftEventFactory;
-+import org.bukkit.craftbukkit.util.CraftMagicNumbers;
++import org.bukkit.event.player.PlayerShearEntityEvent;
-+import org.bukkit.event.block.EntityBlockFormEvent;
 +// CraftBukkit end
  
  public class EntitySnowman extends EntityGolem implements IRangedEntity {
  
-@@ -59,7 +64,7 @@
+@@ -59,7 +63,7 @@
              }
  
              if (this.world.getBiome(new BlockPosition(i, 0, k)).a(new BlockPosition(i, j, k)) > 1.0F) {
@@ -21,7 +20,7 @@
              }
  
              if (!this.world.getGameRules().getBoolean("mobGriefing")) {
-@@ -73,7 +78,7 @@
+@@ -73,7 +77,7 @@
                  BlockPosition blockposition = new BlockPosition(i, j, k);
  
                  if (this.world.getType(blockposition).getMaterial() == Material.AIR && this.world.getBiome(blockposition).a(blockposition) < 0.8F && Blocks.SNOW_LAYER.canPlace(this.world, blockposition)) {
@@ -30,3 +29,19 @@
                  }
              }
          }
+@@ -106,6 +110,15 @@
+         ItemStack itemstack = entityhuman.b(enumhand);
+ 
+         if (itemstack.getItem() == Items.SHEARS && this.hasPumpkin() && !this.world.isClientSide) {
++            // CraftBukkit start
++            PlayerShearEntityEvent event = new PlayerShearEntityEvent((org.bukkit.entity.Player) entityhuman.getBukkitEntity(), this.getBukkitEntity());
++            this.world.getServer().getPluginManager().callEvent(event);
++
++            if (event.isCancelled()) {
++                return false;
++            }
++            // CraftBukkit end
++
+             this.setHasPumpkin(false);
+             itemstack.damage(1, entityhuman);
+         }

src/main/java/org/bukkit/craftbukkit/entity/CraftSnowman.java

@@ -12,12 +12,12 @@ public class CraftSnowman extends CraftGolem implements Snowman {
 
     @Override
     public boolean isDerp() {
-        return getHandle().hasPumpkin();
+        return !getHandle().hasPumpkin();
     }
 
     @Override
     public void setDerp(boolean derpMode) {
-        getHandle().setHasPumpkin(derpMode);
+        getHandle().setHasPumpkin(!derpMode);
     }
 
     @Override