From 998b42f3ef8386316ddfb86dc61b340d6e4aba07 Mon Sep 17 00:00:00 2001
From: PilzAdam <pilzadam@minetest.net>
Date: Sat, 6 Dec 2014 11:43:07 +0100
Subject: [PATCH] Fix possible stacking of books in bookshelf Original author:
 @MT-Modder

---
 nodes.lua | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/nodes.lua b/nodes.lua
index 84f5f94..3fe0fe8 100644
--- a/nodes.lua
+++ b/nodes.lua
@@ -407,8 +407,9 @@ minetest.register_node("default:bookshelf", {
 	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
 		local meta = minetest.get_meta(pos)
 		local inv = meta:get_inventory()
+		local to_stack = inv:get_stack(listname, index)
 		if listname == "books" then
-			if stack:get_name() == "default:book" then
+			if stack:get_name() == "default:book" and to_stack:is_empty() then
 				return 1
 			else
 				return 0