fix crash when adding mods in vanilla

changelog.txt

@@ -1,4 +1,9 @@
 ---------------------------------------------------------------------------------------------------
+Version: 2.1.7
+Date: 2025-02-22
+  Fixes:
+    - Vanilla: Fix runtime crash when adding certain mods to existing game.
+---------------------------------------------------------------------------------------------------
 Version: 2.1.6
 Date: 2025-02-10
   Changes:

control.lua

@@ -21,6 +21,8 @@ end
 script.on_event(defines.events.on_technology_effects_reset, update_recycling_on_reset)
 
 function update_recycling(force)
+  if not force.technologies["alloy-separation"] then return end  -- Tech acts as marker for whether separation recipes exist
+
   if not force.technologies["alloy-separation"].researched then
     -- In this case the player is probably trying to unresearch the tech, and we should fix
     -- recipes as would be expected in this case

info.json

@@ -1,6 +1,6 @@
 {
     "name": "bztin",
-    "version": "2.1.6",
+    "version": "2.1.7",
     "factorio_version": "2.0",
     "title": "Tin",
     "author": "Brevven",