More harddel fixes + Tram sanity check (#57828)

* Fixes a harddel caused by the FUCKING MACHINE VAR WHAT THE FU-

* Fixes a tram related harddel, the proc that removed things from the riders list worked on stuff passed in by Uncrossed, but failed with the qdeleting signal. I've made a wrapper proc to better support these things, added signal handlers, and removed an if check that hid nulls (If it's breaking I need to know)

code/game/machinery/computer/camera_advanced.dm

@@ -101,11 +101,10 @@
 		user.unset_machine()
 
 /obj/machinery/computer/camera_advanced/Destroy()
-	if(current_user)
-		current_user.unset_machine()
 	if(eyeobj)
-		qdel(eyeobj)
+		QDEL_NULL(eyeobj)
 	QDEL_LIST(actions)
+	current_user = null
 	return ..()
 
 /obj/machinery/computer/camera_advanced/on_unset_machine(mob/M)

code/game/objects/objs.dm

@@ -190,18 +190,21 @@
 	ui_interact(user)
 
 /mob/proc/unset_machine()
-	if(machine)
-		machine.on_unset_machine(src)
-		machine = null
+	if(!machine)
+		return
+	UnregisterSignal(machine, COMSIG_PARENT_QDELETING)
+	machine.on_unset_machine(src)
+	machine = null
 
 //called when the user unsets the machine.
 /atom/movable/proc/on_unset_machine(mob/user)
 	return
 
 /mob/proc/set_machine(obj/O)
-	if(src.machine)
+	if(machine)
 		unset_machine()
-	src.machine = O
+	machine = O
+	RegisterSignal(O, COMSIG_PARENT_QDELETING, .proc/unset_machine)
 	if(istype(O))
 		O.obj_flags |= IN_USE
 

code/game/objects/structures/industrial_lift.dm

@@ -163,7 +163,7 @@ GLOBAL_LIST_EMPTY(lifts)
 	. = ..()
 	RegisterSignal(src, COMSIG_MOVABLE_CROSSED, .proc/AddItemOnLift)
 	RegisterSignal(loc, COMSIG_ATOM_CREATED, .proc/AddItemOnLift)//For atoms created on platform
-	RegisterSignal(src, COMSIG_MOVABLE_UNCROSSED, .proc/RemoveItemFromLift)
+	RegisterSignal(src, COMSIG_MOVABLE_UNCROSSED, .proc/UncrossedRemoveItemFromLift)
 	RegisterSignal(src, COMSIG_MOVABLE_BUMP, .proc/GracefullyBreak)
 
 	if(!lift_master_datum)
@@ -174,13 +174,19 @@ GLOBAL_LIST_EMPTY(lifts)
 	. = ..()
 	RegisterSignal(loc, COMSIG_ATOM_CREATED, .proc/AddItemOnLift)//For atoms created on platform
 
-/obj/structure/industrial_lift/proc/RemoveItemFromLift(datum/source, atom/movable/AM)
-	if(!(AM in lift_load))
+/obj/structure/industrial_lift/proc/UncrossedRemoveItemFromLift(datum/source, atom/movable/potential_rider)
+	SIGNAL_HANDLER
+	RemoveItemFromLift(potential_rider)
+
+/obj/structure/industrial_lift/proc/RemoveItemFromLift(atom/movable/potential_rider)
+	SIGNAL_HANDLER
+	if(!(potential_rider in lift_load))
 		return
-	LAZYREMOVE(lift_load, AM)
-	UnregisterSignal(AM, COMSIG_PARENT_QDELETING)
+	LAZYREMOVE(lift_load, potential_rider)
+	UnregisterSignal(potential_rider, COMSIG_PARENT_QDELETING)
 
 /obj/structure/industrial_lift/proc/AddItemOnLift(datum/source, atom/movable/AM)
+	SIGNAL_HANDLER
 	if(istype(AM, /obj/structure/fluff/tram_rail))
 		return
 	if(AM in lift_load)
@@ -254,11 +260,7 @@ GLOBAL_LIST_EMPTY(lifts)
 			var/atom/throw_target = get_edge_target_turf(collided, turn(going, pick(45, -45)))
 			collided.throw_at(throw_target, 200, 4)
 	forceMove(destination)
-	for(var/am in things2move)
-		if(isnull(am))
-			LAZYREMOVE(lift_load, am)//after enough use, one of these always ends up inside despite signals. when they show, we need to scrub them out.
-			continue
-		var/atom/movable/thing = am
+	for(var/atom/movable/thing as anything in things2move)
 		thing.forceMove(destination)
 
 /obj/structure/industrial_lift/proc/use(mob/living/user)

code/modules/clothing/spacesuits/chronosuit.dm

@@ -297,7 +297,6 @@
 
 /obj/effect/chronos_cam/check_eye(mob/user)
 	if(user != holder)
-		user.unset_machine()
 		qdel(src)
 
 /obj/effect/chronos_cam/on_unset_machine(mob/user)