Fix unintended case allowing multiple AI spawns shiftstart (tgstation…

…#59160)

code/controllers/subsystem/job.dm

@@ -259,23 +259,20 @@ SUBSYSTEM_DEF(job)
 		var/mob/dead/new_player/candidate = pick(candidates)
 		AssignRole(candidate, command_position)
 
-/datum/controller/subsystem/job/proc/FillAIPosition()
-	var/ai_selected = FALSE
-	var/datum/job/job = GetJob("AI")
-	if(!job)
-		return FALSE
-	for(var/i = job.total_positions, i > 0, i--)
+/// Attempts to fill out all available AI positions.
+/datum/controller/subsystem/job/proc/fill_ai_positions()
+	var/datum/job/ai_job = GetJob("AI")
+	if(!ai_job)
+		return
+	// In byond for(in to) loops, the iteration is inclusive so we need to stop at ai_job.total_positions - 1
+	for(var/i in ai_job.current_positions to ai_job.total_positions - 1)
 		for(var/level in level_order)
 			var/list/candidates = list()
-			candidates = FindOccupationCandidates(job, level)
+			candidates = FindOccupationCandidates(ai_job, level)
 			if(candidates.len)
 				var/mob/dead/new_player/candidate = pick(candidates)
 				if(AssignRole(candidate, "AI"))
-					ai_selected++
 					break
-	if(ai_selected)
-		return TRUE
-	return FALSE
 
 
 /** Proc DivideOccupations
@@ -341,9 +338,9 @@ SUBSYSTEM_DEF(job)
 	FillHeadPosition()
 	JobDebug("DO, Head Check end")
 
-	//Check for an AI
+	// Fill out any remaining AI positions.
 	JobDebug("DO, Running AI Check")
-	FillAIPosition()
+	fill_ai_positions()
 	JobDebug("DO, AI Check end")
 
 	//Other jobs are now checked