#873 Balm of Return Home fails in magic denied areas.
Magic Denied areas in the game exist to add an additional puzzle challenge, preventing you from using your magic (natural spellcasting, rods, wands, staves, scrolls) in specific areas and forcing you to rely on your own cunning and physical strength. You are also allowed to freely use Potions, Balms, Figurines, and Dusts, all of which function as special spellcasting items which can be used in a Magic Denied area. That way, you're not forced to go through a Magic Denied area without any healing capabilities whatsoever, and instead just have to rely on this special (and limited) class of consumables.
Balms of Return Home function as a balm version of Word of Recall. However, unlike other balms, it fails to work in a Magic Denied area correctly. What happens is the initial Word of Recall effect functions properly, with the spell charging up inside, however, once the charging is complete and Word of Recall triggers, it fizzles out and fails to teleport you due to the Magic Denied area blocking the teleport. The same thing happens if you cast Word of Recall normally in a magic allowed area, then move so you're standing on a Magic Denied tile when the teleport triggers. This is a problem, because it means that if a map's design has a puzzle that can trap you completely in a Magic Denied area, there is literally no means of escape aside from suicide by starvation, which is what the balm would prevent if it functioned correctly. If bad map design forces a player to starve themselves, that's obviously a problem with the map too, but there's no real reason the Balm of Return Home shouldn't work like every other balm and function as a specialized way to use Word of Recall in an environment where spellcasting is otherwise denied. By making it so Balms of Return Home function correctly in a Magic Denied environment, it'd make them consistent with all other balms/potions/dusts/figurines and also remove the possibility of a player being totally trapped due to the map design with no practical means of escape aside from slow starvation.
The fix would require either a) making all Word of Recall teleport effects ignore Magic Denied areas (probably the easiest fix; you can't cast the initial spell in a Magic Denied area but casting it and then running into a Magic Denied area would teleport you, shouldn't create any major exploits as a result of this) or b) have the Balm of Return Home trigger a special teleport effect that ignores Magic Denied areas specifically, which would be the better way to implement it but probably be more complex.
Thanks for the report and analysis. I think implementing the former would be a quick way to fix the problem.
Committed in r21246.