Paper/nms-patches/EntityItem.patch

--- a/net/minecraft/server/EntityItem.java
+++ b/net/minecraft/server/EntityItem.java
@@ -4,6 +4,7 @@
 import javax.annotation.Nullable;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.bukkit.event.player.PlayerPickupItemEvent; // CraftBukkit
 
 public class EntityItem extends Entity {
 
@@ -15,6 +16,7 @@
     private String g;
     private String h;
     public float a;
+    private int lastTick = MinecraftServer.currentTick; // CraftBukkit
 
     public EntityItem(World world, double d0, double d1, double d2) {
         super(world);
@@ -30,6 +32,11 @@
 
     public EntityItem(World world, double d0, double d1, double d2, ItemStack itemstack) {
         this(world, d0, d1, d2);
+        // CraftBukkit start - Can't set null items in the datawatcher
+        if (itemstack == null || itemstack.getItem() == null) {
+            return;
+        }
+        // CraftBukkit end
         this.setItemStack(itemstack);
     }
 
@@ -54,9 +61,12 @@
             this.die();
         } else {
             super.A_();
-            if (this.pickupDelay > 0 && this.pickupDelay != 32767) {
-                --this.pickupDelay;
-            }
+            // CraftBukkit start - Use wall time for pickup and despawn timers
+            int elapsedTicks = MinecraftServer.currentTick - this.lastTick;
+            if (this.pickupDelay != 32767) this.pickupDelay -= elapsedTicks;
+            if (this.age != -32768) this.age += elapsedTicks;
+            this.lastTick = MinecraftServer.currentTick;
+            // CraftBukkit end
 
             this.lastX = this.locX;
             this.lastY = this.locY;
@@ -104,9 +114,11 @@
                 this.motY *= -0.5D;
             }
 
+            /* Craftbukkit start - moved up
             if (this.age != -32768) {
                 ++this.age;
             }
+            // Craftbukkit end */
 
             this.ak();
             if (!this.world.isClientSide) {
@@ -121,6 +133,12 @@
             }
 
             if (!this.world.isClientSide && this.age >= 6000) {
+                // CraftBukkit start - fire ItemDespawnEvent
+                if (org.bukkit.craftbukkit.event.CraftEventFactory.callItemDespawnEvent(this).isCancelled()) {
+                    this.age = 0;
+                    return;
+                }
+                // CraftBukkit end
                 this.die();
             }
 
@@ -162,6 +180,7 @@
                     } else if (itemstack1.getCount() + itemstack.getCount() > itemstack1.getMaxStackSize()) {
                         return false;
                     } else {
+                        if (org.bukkit.craftbukkit.event.CraftEventFactory.callItemMergeEvent(this, entityitem).isCancelled()) return false; // CraftBukkit
                         itemstack1.add(itemstack.getCount());
                         entityitem.pickupDelay = Math.max(entityitem.pickupDelay, this.pickupDelay);
                         entityitem.age = Math.min(entityitem.age, this.age);
@@ -208,6 +227,11 @@
         } else if (!this.getItemStack().isEmpty() && this.getItemStack().getItem() == Items.NETHER_STAR && damagesource.isExplosion()) {
             return false;
         } else {
+            // CraftBukkit start
+            if (org.bukkit.craftbukkit.event.CraftEventFactory.handleNonLivingEntityDamageEvent(this, damagesource, f)) {
+                return false;
+            }
+            // CraftBukkit end
             this.ap();
             this.f = (int) ((float) this.f - f);
             if (this.f <= 0) {
@@ -257,6 +281,12 @@
 
         NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("Item");
 
+        // CraftBukkit start - Handle missing "Item" compounds
+        if (nbttagcompound1 == null) {
+            this.die();
+            return;
+        }
+        // CraftBukkit end
         this.setItemStack(new ItemStack(nbttagcompound1));
         if (this.getItemStack().isEmpty()) {
             this.die();
@@ -270,6 +300,26 @@
             Item item = itemstack.getItem();
             int i = itemstack.getCount();
 
+            // CraftBukkit start - fire PlayerPickupItemEvent
+            int canHold = entityhuman.inventory.canHold(itemstack);
+            int remaining = i - canHold;
+
+            if (this.pickupDelay <= 0 && canHold > 0) {
+                itemstack.setCount(canHold);
+                PlayerPickupItemEvent event = new PlayerPickupItemEvent((org.bukkit.entity.Player) entityhuman.getBukkitEntity(), (org.bukkit.entity.Item) this.getBukkitEntity(), remaining);
+                // event.setCancelled(!entityhuman.canPickUpLoot); TODO
+                this.world.getServer().getPluginManager().callEvent(event);
+                itemstack.setCount(canHold + remaining);
+
+                if (event.isCancelled()) {
+                    return;
+                }
+
+                // Possibly < 0; fix here so we do not have to modify code below
+                this.pickupDelay = 0;
+            }
+            // CraftBukkit end
+
             if (this.pickupDelay == 0 && (this.h == null || 6000 - this.age <= 200 || this.h.equals(entityhuman.getName())) && entityhuman.inventory.pickup(itemstack)) {
                 if (item == Item.getItemOf(Blocks.LOG)) {
                     entityhuman.b((Statistic) AchievementList.g);