From 0724796e51ed655b37c4a80f60c66087c7d16efc Mon Sep 17 00:00:00 2001
From: cheapie <no-email-for-you@example.com>
Date: Sun, 5 Feb 2017 19:28:57 -0600
Subject: Make sure the message is a string before trying to lowercase it

---
 infrastructure/advanced_lane_control_lights.lua | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/infrastructure/advanced_lane_control_lights.lua b/infrastructure/advanced_lane_control_lights.lua
index 195f809..94d7ce1 100644
--- a/infrastructure/advanced_lane_control_lights.lua
+++ b/infrastructure/advanced_lane_control_lights.lua
@@ -63,10 +63,10 @@ for i = 1, 6 do
 			effector = {
 				action = function(pos, node, channel, msg)
 					local setchan = minetest.get_meta(pos):get_string("channel")
-					if setchan ~= channel then
+					if setchan ~= channel or type(msg) ~= "string" then
 						return
 					end
-					msg = msg:lower()
+					msg = string.lower(msg)
 					if (msg=="off") then
 						node.name = "infrastructure:lane_control_lights_1"
 					elseif (msg=="green") then
-- 
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