turns the baseturf var into a part time list (#33705)

code/modules/admin/verbs/randomverbs.dm

@@ -523,7 +523,7 @@ Traitors and the like can also be revived with the previous role mostly intact.
 		SSblackbox.record_feedback("tally", "admin_verb", 1, "Delete") //If you are copy-pasting this, ensure the 2nd parameter is unique to the new proc!
 		if(isturf(D))
 			var/turf/T = D
-			T.ChangeTurf(T.baseturf)
+			T.ScrapeAway()
 		else
 			qdel(D)
 

code/modules/atmospherics/environmental/LINDA_fire.dm

@@ -168,7 +168,7 @@
 			else
 				chance_of_deletion = 100
 			if(prob(chance_of_deletion))
-				T.ChangeTurf(T.baseturf)
+				T.ScrapeAway()
 			else
 				T.to_be_destroyed = FALSE
 				T.max_fire_temperature_sustained = 0

code/modules/mapping/mapping_helpers.dm

@@ -13,11 +13,15 @@
 	. = ..()
 	var/area/thearea = get_area(src)
 	for(var/turf/T in get_area_turfs(thearea, z))
-		if(T.baseturf != T.type) //Don't break indestructible walls and the like
-			T.baseturf = baseturf
+		if(T.baseturfs != T.type) //Don't break indestructible walls and the like
+			T.baseturfs = baseturf
 	return INITIALIZE_HINT_QDEL
 
 
+/obj/effect/baseturf_helper/space
+	name = "space baseturf editor"
+	baseturf = /turf/open/space
+
 /obj/effect/baseturf_helper/asteroid
 	name = "asteroid baseturf editor"
 	baseturf = /turf/open/floor/plating/asteroid

code/modules/mapping/reader.dm

@@ -339,7 +339,7 @@ GLOBAL_DATUM_INIT(_preloader, /dmm_suite/preloader, new)
 
 	if(crds)
 		if(!no_changeturf && ispath(path, /turf))
-			. = crds.ChangeTurf(path, FALSE, TRUE)
+			. = crds.ChangeTurf(path, null, CHANGETURF_DEFER_CHANGE)
 		else
 			. = create_atom(path, crds)//first preloader pass
 

code/modules/mob/living/simple_animal/bot/floorbot.dm

@@ -321,9 +321,9 @@
 		sleep(50)
 		if(mode == BOT_REPAIRING && src.loc == target_turf)
 			if(autotile) //Build the floor and include a tile.
-				target_turf.ChangeTurf(/turf/open/floor/plasteel)
+				target_turf.PlaceOnTop(/turf/open/floor/plasteel)
 			else //Build a hull plating without a floor tile.
-				target_turf.ChangeTurf(/turf/open/floor/plating)
+				target_turf.PlaceOnTop(/turf/open/floor/plating)
 
 	else
 		var/turf/open/floor/F = target_turf

code/modules/mob/living/simple_animal/hostile/mining_mobs/necropolis_tendril.dm

@@ -39,7 +39,7 @@
 	for(var/F in RANGE_TURFS(1, src))
 		if(ismineralturf(F))
 			var/turf/closed/mineral/M = F
-			M.ChangeTurf(M.turf_type,FALSE,FALSE,TRUE)
+			M.ChangeTurf(M.turf_type, null, CHANGETURF_IGNORE_AIR)
 	gps = new /obj/item/device/gps/internal(src)
 
 /mob/living/simple_animal/hostile/spawner/lavaland/Destroy()

code/modules/reagents/chemistry/reagents/pyrotechnic_reagents.dm

@@ -51,7 +51,7 @@
 	if(isplatingturf(T))
 		var/turf/open/floor/plating/F = T
 		if(prob(10 + F.burnt + 5*F.broken)) //broken or burnt plating is more susceptible to being destroyed
-			F.ChangeTurf(F.baseturf)
+			F.ScrapeAway()
 	if(isfloorturf(T))
 		var/turf/open/floor/F = T
 		if(prob(reac_volume))
@@ -65,7 +65,7 @@
 	if(iswallturf(T))
 		var/turf/closed/wall/W = T
 		if(prob(reac_volume))
-			W.ChangeTurf(/turf/open/floor/plating)
+			W.ScrapeAway()
 
 /datum/reagent/clf3/reaction_mob(mob/living/M, method=TOUCH, reac_volume)
 	if(istype(M))

code/modules/shuttle/on_move.dm

@@ -7,8 +7,15 @@ All ShuttleMove procs go here
 // Called on every turf in the shuttle region, returns a bitflag for allowed movements of that turf
 // returns the new move_mode (based on the old)
 /turf/proc/fromShuttleMove(turf/newT, turf_type, list/baseturf_cache, move_mode)
-	if(!(move_mode & MOVE_AREA) || (istype(src, turf_type) && baseturf_cache[baseturf]))
+	if(!(move_mode & MOVE_AREA))
 		return move_mode
+	if(istype(src, turf_type))
+		if(length(baseturfs))
+			if(baseturf_cache[baseturfs[1]])
+				return move_mode
+		else if(baseturf_cache[baseturfs])
+			return move_mode
+
 	return move_mode | MOVE_TURF | MOVE_CONTENTS
 
 // Called from the new turf before anything has been moved
@@ -45,9 +52,7 @@ All ShuttleMove procs go here
 	if(newT == src) // In case of in place shuttle rotation shenanigans.
 		return
 	//Destination turf changes
-	var/destination_turf_type = newT.type
-	newT = copyTurf(newT)
-	newT.baseturf = destination_turf_type
+	newT.CopyOnTop(src, 1, 0) // We only want a surface copy
 	//Air stuff
 	newT.blocks_air = TRUE
 	newT.air_update_turf(TRUE)
@@ -63,9 +68,8 @@ All ShuttleMove procs go here
 /turf/proc/afterShuttleMove(turf/oldT, turf_type, baseturf_type, rotation)
 	//Dealing with the turf we left behind
 	oldT.TransferComponents(src)
-	oldT.ChangeTurf(turf_type, baseturf_type, FALSE, TRUE)
+	oldT.ChangeTurf(turf_type, baseturf_type, CHANGETURF_IGNORE_AIR) // TODO: make this oldT.ScrapeAway() which requires templating all shuttles
 
-	// Rotate and let the air move again
 	if(rotation)
 		shuttleRotate(rotation) //see shuttle_rotate.dm
 

code/modules/shuttle/shuttle.dm

@@ -465,7 +465,7 @@
 		var/turf/T1 = L1[i]
 		if(!T1)
 			continue
-		if(T0.type != T0.baseturf)
+		if(T0.type != T0.baseturfs)
 			ripple_turfs += T1
 
 	return ripple_turfs