Get skull data before destroying block. Fixes BUKKIT-2723

Skull blocks store their type in a tile entity and use their block data
as rotation. When breaking a block the block data is used for determining
what item to drop. Simply changing this to use the skull method for getting
their drop data is not enough because their tile entity is already gone.
Therefore we have to special case skulls to get the correct data _and_ get
that data before breaking the block.

src/main/java/net/minecraft/server/Explosion.java

@@ -264,8 +264,14 @@ public class Explosion {
 
                 // CraftBukkit - stop explosions from putting out fire
                 if (l > 0 && l != Block.FIRE.id) {
-                    // CraftBukkit
+                    // CraftBukkit start - special case skulls, add yield
-                    Block.byId[l].dropNaturally(this.world, i, j, k, this.world.getData(i, j, k), event.getYield(), 0);
+                    int data = this.world.getData(i, j, k);
+                    if (l == Block.SKULL.id) {
+                        data = Block.SKULL.getDropData(this.world, i, j, k);
+                    }
+
+                    Block.byId[l].dropNaturally(this.world, i, j, k, data, event.getYield(), 0);
+                    // CraftBukkit end
                     if (this.world.setRawTypeIdAndData(i, j, k, 0, 0, this.world.isStatic)) {
                         this.world.applyPhysics(i, j, k, 0);
                     }

src/main/java/net/minecraft/server/ItemInWorldManager.java

@@ -291,6 +291,11 @@ public class ItemInWorldManager {
             int l = this.world.getTypeId(i, j, k);
             if (Block.byId[l] == null) return false; // CraftBukkit - a plugin set block to air without cancelling
             int i1 = this.world.getData(i, j, k);
+            // CraftBukkit start - special case skulls, their item data comes from a tile entity
+            if (l == Block.SKULL.id) {
+                i1 = Block.SKULL.getDropData(world, i, j, k);
+            }
+            // CraftBukkit end
 
             this.world.a(this.player, 2001, i, j, k, l + (this.world.getData(i, j, k) << 12));
             boolean flag = this.d(i, j, k);

src/main/java/org/bukkit/craftbukkit/CraftWorld.java

@@ -1083,7 +1083,11 @@ public class CraftWorld implements World {
         int blockY = block.getY();
         int blockZ = block.getZ();
         // following code is lifted from Explosion.a(boolean), and modified
-        net.minecraft.server.Block.byId[blockId].dropNaturally(this.world, blockX, blockY, blockZ, block.getData(), yield, 0);
+        int data = block.getData();
+        if (blockId == net.minecraft.server.Block.SKULL.id) {
+            data = net.minecraft.server.Block.SKULL.getDropData(this.world, blockX, blockY, blockZ);
+        }
+        net.minecraft.server.Block.byId[blockId].dropNaturally(this.world, blockX, blockY, blockZ, data, yield, 0);
         block.setType(org.bukkit.Material.AIR);
         // not sure what this does, seems to have something to do with the 'base' material of a block.
         // For example, WOODEN_STAIRS does something with WOOD in this method

src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java

@@ -342,15 +342,22 @@ public class CraftBlock implements Block {
     }
 
     public boolean breakNaturally() {
+        // Order matters here, need to drop before setting to air so skulls can get their data
         net.minecraft.server.Block block = net.minecraft.server.Block.byId[this.getTypeId()];
         byte data = getData();
+        boolean result = false;
+
+        if (block != null) {
+            if (block.id == net.minecraft.server.Block.SKULL.id) {
+                data = (byte) block.getDropData(chunk.getHandle().world, x, y, z);
+            }
+
+            block.dropNaturally(chunk.getHandle().world, x, y, z, data, 1.0F, 0);
+            result = true;
+        }
 
         setTypeId(Material.AIR.getId());
-        if (block != null) {
+        return result;
-            block.dropNaturally(chunk.getHandle().world, x, y, z, data, 1.0F, 0);
-            return true;
-        }
-        return false;
     }
 
     public boolean breakNaturally(ItemStack item) {