Merge pull request #3583 from CHOMPStation2/upstream-merge-12091

[MIRROR] Fixes AI subsystem locking up on trying to process null entries

code/controllers/subsystems/ai.dm

@@ -10,7 +10,7 @@ SUBSYSTEM_DEF(ai)
 	var/list/currentrun = list()
 
 	var/slept_mobs = 0
-	var/list/process_z = list()	
+	var/list/process_z = list()
 
 /datum/controller/subsystem/ai/stat_entry(msg_prefix)
 	..("P: [processing.len] | S: [slept_mobs]")
@@ -32,10 +32,13 @@ SUBSYSTEM_DEF(ai)
 	while(currentrun.len)
 		var/datum/ai_holder/A = currentrun[currentrun.len]
 		--currentrun.len
-		var/mob/living/L = A.holder	//VOREStation Edit Start
-		if(!A || QDELETED(A) || !L?.loc || A.busy) // Doesn't exist or won't exist soon or not doing it this tick
+		if(!A || QDELETED(A) || A.busy) // Doesn't exist or won't exist soon or not doing it this tick
 			continue
-		
+
+		var/mob/living/L = A.holder	//VOREStation Edit Start
+		if(!L?.loc)
+			continue
+
 		if(process_z[get_z(L)] || !L.low_priority) //VOREStation Edit End
 			A.handle_strategicals()
 		else

code/modules/ai/ai_holder.dm

@@ -131,7 +131,7 @@
 	IF_VV_OPTION("mass_edit_finish")
 		if(!check_rights(R_ADMIN))
 			return
-		
+
 		var/list/before = snapshot //This PROBABLY works, right?
 		snapshot = null
 		var/list/after = vars.Copy() //'vars' appears to be special in that vars.Copy produces a flat list of keys with no values. It seems that 'vars[key]' is handled somewhere in the byond engine differently than normal lists.
@@ -183,7 +183,7 @@
 				found += M
 			choices["[typechoice] ([found.len])"] = found // Prettified name for the user input below)
 			searching = found // Now we only search the list we just made, because of the order of our types list, each subsequent list will be a subset of the one we just finished
-		
+
 		var/choice = tgui_input_list(usr,"Based on your AI holder's mob location, we'll edit mobs on Z [levels_working.Join(",")]. What types do you want to alter?", "Types", choices)
 		if(!choice)
 			href_list["datumrefresh"] = "\ref[src]"
@@ -201,7 +201,7 @@
 					L.ai_holder.vars[newvar] = after[newvar]
 				else
 					to_chat(usr,"<span class='warning'>Skipping unavailable var '[newvar]' on: [L] [ADMIN_COORDJMP(L)]</span>")
-		
+
 		to_chat(usr,"<span class='notice'>Mass AI edit done.</span>")
 		href_list["datumrefresh"] = "\ref[src]"
 
@@ -291,6 +291,9 @@
 
 // 'Tactical' processes such as moving a step, meleeing an enemy, firing a projectile, and other fairly cheap actions that need to happen quickly.
 /datum/ai_holder/proc/handle_tactics()
+	if(!istype(holder) || QDELETED(holder))
+		qdel(src)
+		return
 	if(holder.key && !autopilot)
 		return
 	handle_special_tactic()
@@ -298,6 +301,9 @@
 
 // 'Strategical' processes that are more expensive on the CPU and so don't get run as often as the above proc, such as A* pathfinding or robust targeting.
 /datum/ai_holder/proc/handle_strategicals()
+	if(!istype(holder) || QDELETED(holder))
+		qdel(src)
+		return
 	if(holder.key && !autopilot)
 		return
 	handle_special_strategical()