Ensure modified assembling_machine_list is returned to caller

Resolves pyanodon/pybugreports#732
Thanks <@66281942261182464> for the report

changelog.txt

@@ -4,6 +4,7 @@ Date: ?
   Changes:
     - Fixed digosaurs pywiki page missing [item=dried-meat] → 1 ore info. Resolves https://github.com/pyanodon/pybugreports/issues/725
     - Fixed a crash when clicking on the "Unavaliable" button in the fish TURD while dousing pumps is selected.
+    - Fixed a crash migrating TURDs
 ---------------------------------------------------------------------------------------------------
 Version: 3.0.23
 Date: 2024-11-17

scripts/turd/turd.lua

@@ -386,7 +386,7 @@ end
 local function apply_turd_bonus(force, master_tech_name, tech_upgrade, assembling_machine_list)
 	local turd_bonuses = storage.turd_bonuses[force.index] or {}
 	local selection = turd_bonuses[master_tech_name] or NOT_SELECTED
-	if selection == NOT_SELECTED then return end
+	if selection == NOT_SELECTED then return assembling_machine_list end
 	local sub_tech = tech_upgrade.sub_techs[selection]
 
 	local recipes = force.recipes
@@ -406,14 +406,15 @@ local function apply_turd_bonus(force, master_tech_name, tech_upgrade, assemblin
 			storage.turd_machine_replacements[force.index][effect.old] = effect.new
 		end
 	end
+	return assembling_machine_list
 end
 
 local function reapply_turd_bonuses(force)
 	storage.turd_unlocked_modules[force.index] = {}
 	local assembling_machine_list = find_all_assembling_machines(force)
 
 	for master_tech_name, tech_upgrade in pairs(tech_upgrades) do
-		apply_turd_bonus(force, master_tech_name, tech_upgrade, assembling_machine_list)
+		assembling_machine_list = apply_turd_bonus(force, master_tech_name, tech_upgrade, assembling_machine_list)
 	end
 end