Merge pull request #15338 from tkdrg/whoa

[s]Fixes server crash by abusing containment fields

code/modules/power/singularity/containment_field.dm

@@ -67,25 +67,19 @@
 /obj/machinery/field
 	var/hasShocked = 0 //Used to add a delay between shocks. In some cases this used to crash servers by spawning hundreds of sparks every second.
 
-/obj/machinery/field/CanPass(mob/mover, turf/target, height=0)
+/obj/machinery/field/CanPass(atom/movable/mover, turf/target, height=0)
+	if(hasShocked)
+		return 0
 	if(isliving(mover)) // Don't let mobs through
 		shock(mover)
 		return 0
-	return ..()
-
-/obj/machinery/field/CanPass(obj/mover, turf/target, height=0)
-	if((istype(mover, /obj/machinery) && !istype(mover, /obj/singularity)) || \
-		istype(mover, /obj/structure) || \
-		istype(mover, /obj/mecha))
+	if(istype(mover, /obj/machinery) || istype(mover, /obj/structure) || istype(mover, /obj/mecha))
 		bump_field(mover)
 		return 0
 	return ..()
 
 /obj/machinery/field/proc/shock(mob/living/user)
-	if(hasShocked)
-		return 0
 	if(isliving(user))
-		hasShocked = 1
 		var/shock_damage = min(rand(30,40),rand(30,40))
 
 		if(iscarbon(user))
@@ -104,14 +98,18 @@
 
 		user.updatehealth()
 		bump_field(user)
-
-		spawn(5)
-			hasShocked = 0
 	return
 
+/obj/machinery/field/proc/clear_shock()
+	hasShocked = 0
+
 /obj/machinery/field/proc/bump_field(atom/movable/AM as mob|obj)
+	if(hasShocked)
+		return 0
+	hasShocked = 1
 	var/datum/effect_system/spark_spread/s = new /datum/effect_system/spark_spread
 	s.set_up(5, 1, AM.loc)
 	s.start()
 	var/atom/target = get_edge_target_turf(AM, get_dir(src, get_step_away(AM, src)))
 	AM.throw_at(target, 200, 4)
+	addtimer(src, "clear_shock", 5)