Fixes lavaboat buckling (#34450)

* Buckle order

* lavaboats

code/game/objects/buckling.dm

@@ -45,11 +45,13 @@
 
 	if((!can_buckle && !force) || M.buckled || (buckled_mobs.len >= max_buckled_mobs) || (buckle_requires_restraints && !M.restrained()) || M == src)
 		return FALSE
+	M.buckling = src
 	if(!M.can_buckle() && !force)
 		if(M == usr)
 			to_chat(M, "<span class='warning'>You are unable to buckle yourself to [src]!</span>")
 		else
 			to_chat(usr, "<span class='warning'>You are unable to buckle [M] to [src]!</span>")
+		M.buckling = null
 		return FALSE
 
 	if(M.pulledby && buckle_prevents_pull)
@@ -58,6 +60,7 @@
 	if(!check_loc && M.loc != loc)
 		M.forceMove(loc)
 
+	M.buckling = null
 	M.buckled = src
 	M.setDir(dir)
 	buckled_mobs |= M

code/game/turfs/simulated/lava.dm

@@ -111,15 +111,17 @@
 				continue	//YOU'RE FLYING OVER IT
 			if("lava" in L.weather_immunities)
 				continue
-			if(L.buckled)
-				if(isobj(L.buckled))
-					var/obj/O = L.buckled
-					if(O.resistance_flags & LAVA_PROOF)
-						continue
-				if(isliving(L.buckled)) //Goliath riding
-					var/mob/living/live = L.buckled
-					if("lava" in live.weather_immunities)
-						continue
+			var/buckle_check = L.buckling
+			if(!buckle_check)
+				buckle_check = L.buckled
+			if(isobj(buckle_check))
+				var/obj/O = buckle_check
+				if(O.resistance_flags & LAVA_PROOF)
+					continue
+			else if(isliving(buckle_check))
+				var/mob/living/live = buckle_check
+				if("lava" in live.weather_immunities)
+					continue
 
 			L.adjustFireLoss(20)
 			if(L) //mobs turning into object corpses could get deleted here.