until you've kept vs unitl you keep

Question

is there any difference in nuance in meaning between the two sentences?(present tense version and present perfect tense version)

A) 'You won't leave here until you 've kept your promise to marry Linton'

B) 'You won't leave here until you keep your promise to marry Linton'

Answer 1

The difference is that A is notionally looking backward from the time after leaving, whereas B is looking forward from now.

In this case I can't see any practical consequence of this difference.