From 1a918be6588bbdd17bbe7793d9acad334ccbb5a1 Mon Sep 17 00:00:00 2001
From: Florian Scandella <flo@chilicode.com>
Date: Tue, 29 Aug 2017 22:52:59 +0200
Subject: [PATCH] only calculate difference when it's the same item

---
 .../tile/inventory/AppEngInternalInventory.java   | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/main/java/appeng/tile/inventory/AppEngInternalInventory.java b/src/main/java/appeng/tile/inventory/AppEngInternalInventory.java
index 35b823223..a711e1af9 100644
--- a/src/main/java/appeng/tile/inventory/AppEngInternalInventory.java
+++ b/src/main/java/appeng/tile/inventory/AppEngInternalInventory.java
@@ -119,13 +119,16 @@ public class AppEngInternalInventory extends ItemStackHandler implements IIntern
 			ItemStack added = this.getStackInSlot( slot ).copy();
 			ItemStack removed = this.previousStack.copy();
 
-			if( this.currentOp == InvOperation.INSERT )
+			if( !added.isEmpty() && !removed.isEmpty() && Platform.itemComparisons().isEqualItem( added, removed ) )
 			{
-				added.grow( -removed.getCount() );
-			}
-			else if( this.currentOp == InvOperation.EXTRACT )
-			{
-				removed.grow( -added.getCount() );
+				if( this.currentOp == InvOperation.INSERT )
+				{
+					added.grow( -removed.getCount() );
+				}
+				else if( this.currentOp == InvOperation.EXTRACT )
+				{
+					removed.grow( -added.getCount() );
+				}
 			}
 			this.getTileEntity().onChangeInventory( this, slot, this.currentOp, removed, added );
 			this.getTileEntity().saveChanges();