Teleporting while buckled to something will take you with it (#87725)

## About The Pull Request

closes #35872 (this bug is 6+ years old)

`/proc/do_teleport(...)` now has extra checks for atoms with buckled
mobs attempting to pass through it, assuring that they also pass through
with the vehicle

`/atom/movable/proc/is_buckle_possible(...)` will skip density checks if
the bucklable and the target share the same tile, because at that point
it doesn't really matter (it also interfered with density checks when
teleporting)
## Gleeble


![fucked-up-dog-geeble](https://github.com/user-attachments/assets/6ef814c2-d8f2-48fc-82a3-98517bf6a492)

## Changelog

🆑
fix: Teleporting while buckled to something now works as expected
fix: You can buckle to anything if you share the same tile (cause at
that point it doesn't matter if there's a wall, right?)
/🆑

code/datums/helper_datums/teleport.dm

@@ -23,7 +23,7 @@
 
 	// argument handling
 	// if the precision is not specified, default to 0, but apply BoH penalties
-	if (isnull(precision))
+	if(isnull(precision))
 		precision = 0
 
 	switch(channel)
@@ -40,7 +40,7 @@
 					to_chat(MM, span_warning("The bluespace interface on your bag of holding interferes with the teleport!"))
 
 			// if effects are not specified and not explicitly disabled, sparks
-			if ((!effectin || !effectout) && !no_effects)
+			if((!effectin || !effectout) && !no_effects)
 				var/datum/effect_system/spark_spread/sparks = new
 				sparks.set_up(5, 1, teleatom)
 				if (!effectin)
@@ -78,10 +78,16 @@
 		return TRUE
 
 	tele_play_specials(teleatom, curturf, effectin, asoundin)
+
 	var/success = teleatom.forceMove(destturf)
-	if(success)
-		log_game("[key_name(teleatom)] has teleported from [loc_name(curturf)] to [loc_name(destturf)]")
-		tele_play_specials(teleatom, destturf, effectout, asoundout)
+	if(!success)
+		return FALSE
+
+	. = TRUE
+	/* Past this point, the teleport is successful and you can assume that they're already there */
+
+	log_game("[key_name(teleatom)] has teleported from [loc_name(curturf)] to [loc_name(destturf)]")
+	tele_play_specials(teleatom, destturf, effectout, asoundout)
 
 	if(ismob(teleatom))
 		var/mob/M = teleatom
@@ -90,7 +96,22 @@
 
 	SEND_SIGNAL(teleatom, COMSIG_MOVABLE_POST_TELEPORT, destination, channel)
 
-	return TRUE
+	//We need to be sure that the buckled mobs can teleport too
+	if(teleatom.has_buckled_mobs())
+		for(var/mob/living/rider in teleatom.buckled_mobs)
+			//just in case it fails, but the mob gets unbuckled anyways even if it passes
+			teleatom.unbuckle_mob(rider, TRUE, FALSE)
+
+			var/rider_success = do_teleport(rider, destturf, precision, channel=channel, no_effects=TRUE)
+			if(!rider_success)
+				continue
+
+			if(get_turf(rider) != destturf) //precision made them teleport somewhere else
+				to_chat(rider, span_warning("As you reorient your senses, you realize you aren't riding [teleatom] anymore!"))
+				continue
+
+			// [mob/living].forceMove() forces mobs to unbuckle, so we need to buckle them again
+			teleatom.buckle_mob(rider, force=TRUE)
 
 /proc/tele_play_specials(atom/movable/teleatom, atom/location, datum/effect_system/effect, sound)
 	if(!location)

code/game/objects/buckling.dm

@@ -215,23 +215,25 @@
 	if(target == src)
 		return FALSE
 
-	// Check if the target to buckle isn't INSIDE OF A WALL
-	if(!isopenturf(loc) || !isopenturf(target.loc))
-		return FALSE
-
-	// Check if the target to buckle isn't A SOLID OBJECT (not including vehicles)
 	var/turf/ground = get_turf(src)
-	if(ground.is_blocked_turf(exclude_mobs = TRUE, source_atom = src))
-		return FALSE
+	// If we're not already on the same turf as our target...
+	if(get_turf(target) != ground)
+		// Check if the target to buckle isn't INSIDE OF A WALL
+		if(!isopenturf(loc) || !isopenturf(target.loc))
+			return FALSE
+
+		// Check if the target to buckle isn't INSIDE A SOLID OBJECT (not including vehicles)
+		if(ground.is_blocked_turf(exclude_mobs = TRUE, source_atom = src))
+			return FALSE
+
+		// If we're checking the loc, make sure the target is on the thing we're bucking them to.
+		if(check_loc && !target.Adjacent(src))
+			return FALSE
 
 	// Check if this atom can have things buckled to it.
 	if(!can_buckle && !force)
 		return FALSE
 
-	// If we're checking the loc, make sure the target is on the thing we're bucking them to.
-	if(check_loc && !target.Adjacent(src))
-		return FALSE
-
 	// Make sure the target isn't already buckled to something.
 	if(target.buckled)
 		return FALSE