From d7561ddb82cfa48d8eb856c97b63bc978ebc3856 Mon Sep 17 00:00:00 2001
From: Ellpeck <megamaximal@gmail.com>
Date: Fri, 10 Mar 2017 23:15:50 +0100
Subject: [PATCH] fix an exception in the booklet with broken furnace recipes

---
 .../actuallyadditions/mod/booklet/page/PageFurnace.java   | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/main/java/de/ellpeck/actuallyadditions/mod/booklet/page/PageFurnace.java b/src/main/java/de/ellpeck/actuallyadditions/mod/booklet/page/PageFurnace.java
index ce37f479d..3f9e887c4 100644
--- a/src/main/java/de/ellpeck/actuallyadditions/mod/booklet/page/PageFurnace.java
+++ b/src/main/java/de/ellpeck/actuallyadditions/mod/booklet/page/PageFurnace.java
@@ -12,6 +12,7 @@ package de.ellpeck.actuallyadditions.mod.booklet.page;
 
 import de.ellpeck.actuallyadditions.api.booklet.internal.GuiBookletBase;
 import de.ellpeck.actuallyadditions.mod.booklet.gui.GuiBooklet;
+import de.ellpeck.actuallyadditions.mod.util.StackUtil;
 import net.minecraft.item.ItemStack;
 import net.minecraft.item.crafting.FurnaceRecipes;
 import net.minecraftforge.fml.client.config.GuiUtils;
@@ -32,8 +33,11 @@ public class PageFurnace extends BookletPage{
 
     private static ItemStack getInputForOutput(ItemStack output){
         for(Map.Entry<ItemStack, ItemStack> entry : FurnaceRecipes.instance().getSmeltingList().entrySet()){
-            if(entry.getValue().isItemEqual(output)){
-                return entry.getKey();
+            ItemStack stack = entry.getValue();
+            if(StackUtil.isValid(stack)){
+                if(stack.isItemEqual(output)){
+                    return entry.getKey();
+                }
             }
         }
         return null;