leaky abstraction

RU: протекающая абстракция

An abstraction that fails to fully hide the layer below it, so implementation detail becomes visible to the user — most often when the layer below fails, runs slow, or hits a limit. Joel Spolsky's Law of Leaky Abstractions states that all non-trivial abstractions are leaky to some degree: they save time working but not time learning, because a user still has to understand the layer below when it shows through.