bugfixing and ready for 0.4.16 release

-fixing #173
-making migration for 0.4.12 consume less RAM
- minor readme update for 0.4.16 release

Author: kyranf

README.md

@@ -1,7 +1,7 @@
 # Robot Army mod for Factorio V1.1+
 
 ## Version
-0.4.15,
+0.4.16,
 Known to be compatible with Factorio v1.1.42. Requires at least v1.1.38 due to mod script API features used.
 
 

migrations/robotarmy_0.4.12.lua

@@ -26,7 +26,7 @@ for i, force_ in pairs(game.forces) do
 
         -- get the list of units
         -- for each unit in the list, check the type and name is what we want, add to the list.
-        local units = surface_.find_units({area = {{-1000, -1000}, {1000, 1000}}, force = force_.name, condition = "same"})
+        local units = surface_.find_units({area = {{-500, -500}, {500, 500}}, force = force_.name, condition = "same"})
         for _, unitFound in pairs(units) do
             if names[unitFound.name] then
                 if unitFound.valid then
@@ -41,4 +41,5 @@ for i, force_ in pairs(game.forces) do
     end
 end
 
-Game.print_all(string.format("units added in robot army migration script: %d", numUnitsAdded))
+Game.print_all(string.format("units added in robot army migration script: %d", numUnitsAdded))
+Game.print_all("Note that any units away from starting area (+-500 tiles) should be re-deployed for improved AI behaviours.")

robolib/retreat.lua

@@ -14,6 +14,10 @@ function orderSquadToRetreat(squad)
 		global.DroidAssemblers[squad.force.name], squad.unitGroup.position)
     local currentPos = squad.unitGroup.position
 
+
+    if not  squad.unitGroup then return end;
+    if not  squad.unitGroup.valid then return end;
+    
 	if assembler then
         local retreatPos = getDroidSpawnLocation(assembler)
         if not retreatPos then