Any Planet Start: Prevent crashes

lignumis/prototypes/compatibility/any-planet-start-final.lua

@@ -4,29 +4,31 @@ if not mods["any-planet-start"] then return end
 
 local target_planet = settings.startup["aps-planet"].value
 
-if target_planet == "none" or target_planet == "nauvis" then return end
+if not target_planet or target_planet == "none" or target_planet == "nauvis" then return end
 
 Technology:new("tree-seeding"):setPrerequisites({ "wood-science-pack" })
 
 
 -- Switch planet discovery technology to the new planet
 local planet_discovery = data.raw.technology["planet-discovery-" .. target_planet] or data.raw.technology["moon-discovery-" .. target_planet]
-Technology:new(planet_discovery)
-    :assign({
-        enabled = true,
-        hidden = false,
-        unit = {
-            count = 100,
-            ingredients = {
-                { "wood-science-pack",  1 },
-                { "steam-science-pack", 1 }
-            },
-            time = 30
-        }
-    })
-    :setPrerequisites({ "provisional-rocketry" })
-Technology:new("iron-processing"):replacePrerequisite("planet-discovery-nauvis", planet_discovery.name)
-Technology:new("copper-processing"):replacePrerequisite("planet-discovery-nauvis", planet_discovery.name)
+if planet_discovery then
+    Technology:new(planet_discovery)
+        :assign({
+            enabled = true,
+            hidden = false,
+            unit = {
+                count = 100,
+                ingredients = {
+                    { "wood-science-pack",  1 },
+                    { "steam-science-pack", 1 }
+                },
+                time = 30
+            }
+        })
+        :setPrerequisites({ "provisional-rocketry" })
+    Technology:new("iron-processing"):replacePrerequisite("planet-discovery-nauvis", planet_discovery.name)
+    Technology:new("copper-processing"):replacePrerequisite("planet-discovery-nauvis", planet_discovery.name)
+end
 
 
 -- Vulcanus