From a8ec7876a68cb4abbf2d517526822f17d7ac0efc Mon Sep 17 00:00:00 2001
From: kwolekr <kwolekr@minetest.net>
Date: Tue, 27 Jan 2015 22:36:53 -0500
Subject: [PATCH] Prevent null concatenation when /deleteblocks is provided an
 incorrect format

---
 builtin/game/chatcommands.lua | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/builtin/game/chatcommands.lua b/builtin/game/chatcommands.lua
index 8ce1cfef5..2d94817e8 100644
--- a/builtin/game/chatcommands.lua
+++ b/builtin/game/chatcommands.lua
@@ -420,6 +420,10 @@ core.register_chatcommand("deleteblocks", {
 			p2 = p1
 		else
 			local pos1, pos2 = unpack(param:split(") ("))
+			if pos1 == nil or pos2 == nil then
+				return false, "Incorrect area format. Expected: (x1,y1,z1) (x2,y2,z2)"
+			end
+
 			p1 = core.string_to_pos(pos1 .. ")")
 			p2 = core.string_to_pos("(" .. pos2)