Merge pull request #10215 from Ghommie/Ghommie-cit473

Ports "Fixes ChangeTurf CHANGETURF_INHERIT_AIR flag and add it to all calls."

code/game/objects/effects/effect_system/effects_foam.dm

@@ -123,7 +123,7 @@
 	if(metal)
 		var/turf/T = get_turf(src)
 		if(isspaceturf(T)) //Block up any exposed space
-			T.PlaceOnTop(/turf/open/floor/plating/foam)
+			T.PlaceOnTop(/turf/open/floor/plating/foam, flags = CHANGETURF_INHERIT_AIR)
 		for(var/direction in GLOB.cardinals)
 			var/turf/cardinal_turf = get_step(T, direction)
 			if(get_area(cardinal_turf) != get_area(T)) //We're at an area boundary, so let's block off this turf!

code/game/objects/items/stacks/stack.dm

@@ -192,9 +192,14 @@
 		var/obj/O
 		if(R.max_res_amount > 1) //Is it a stack?
 			O = new R.result_type(usr.drop_location(), R.res_amount * multiplier)
-		else
+		else if(ispath(R.result_type, /turf))
+			var/turf/T = usr.drop_location()
+			if(!isturf(T))
+				return
+			T.PlaceOnTop(R.result_type, flags = CHANGETURF_INHERIT_AIR)
 			O = new R.result_type(usr.drop_location())
-		O.setDir(usr.dir)
+		if(O)
+			O.setDir(usr.dir)
 		use(R.req_amount * multiplier)
 
 		//START: oh fuck i'm so sorry

code/game/objects/items/twohanded.dm

@@ -872,7 +872,7 @@
 		user.visible_message("<span class='danger'>[user] blasts \the [target] with \the [src]!</span>")
 		playsound(target, 'sound/magic/disintegrate.ogg', 100, 1)
 		W.break_wall()
-		W.ScrapeAway()
+		W.ScrapeAway(flags = CHANGETURF_INHERIT_AIR)
 		return
 
 //HF blade

code/game/objects/structures/lattice.dm

@@ -60,7 +60,7 @@
 		to_chat(user, "<span class='notice'>You build a floor.</span>")
 		var/turf/T = src.loc
 		if(isspaceturf(T))
-			T.PlaceOnTop(/turf/open/floor/plating)
+			T.PlaceOnTop(/turf/open/floor/plating, flags = CHANGETURF_INHERIT_AIR)
 			qdel(src)
 			return TRUE
 	return FALSE

code/game/objects/structures/stairs.dm

@@ -102,13 +102,13 @@
 /obj/structure/stairs/proc/force_open_above()
 	var/turf/open/openspace/T = get_step_multiz(get_turf(src), UP)
 	if(T && !istype(T))
-		T.ChangeTurf(/turf/open/openspace)
+		T.ChangeTurf(/turf/open/openspace, flags = CHANGETURF_INHERIT_AIR)
 
 /obj/structure/stairs/proc/on_multiz_new(turf/source, dir)
 	if(dir == UP)
 		var/turf/open/openspace/T = get_step_multiz(get_turf(src), UP)
 		if(T && !istype(T))
-			T.ChangeTurf(/turf/open/openspace)
+			T.ChangeTurf(/turf/open/openspace, flags = CHANGETURF_INHERIT_AIR)
 
 /obj/structure/stairs/intercept_zImpact(atom/movable/AM, levels = 1)
 	. = ..()