Bugfix & style

- added initialization of turret index
- removed unnecessary variable

changelog.txt

@@ -1,4 +1,9 @@
 ---------------------------------------------------------------------------------------------------
+Version: 0.18.3
+Date: 2020-03-21
+  Bugfixes:
+    - Added missing initialization of turret index
+---------------------------------------------------------------------------------------------------
 Version: 0.18.2
 Date: 2020-03-20
   Changes:

control.lua

@@ -4,9 +4,9 @@
 script.on_event({defines.events.on_tick}, function (event)
 	--Every minute the surface is rescanned for ammo-turret type entities. This is stored in the global table. 
 	if event.tick%3600 == 0 or global.turret_entities == nil then
-		local planet = game.surfaces
-		for index,_ in pairs(planet) do
-			global.turret_entities[index] = planet[index].find_entities_filtered{type = "ammo-turret"}
+		global.turret_entities = {}
+		for index,surface in pairs(game.surfaces) do
+			global.turret_entities[index] = surface.find_entities_filtered{type = "ammo-turret"}
 		end
 	end
 	if event.tick%600 == 0 then

info.json

@@ -1,6 +1,6 @@
 {
     "name": "Gun_Turret_Alerts",
-    "version": "0.18.2",
+    "version": "0.18.3",
     "title": "Gun_Turret_Alerts",
     "author": "Wyrrrd",
     "factorio_version": "0.18",