Dead-lock in replaced package scripts

[Ondřej Surý <ondrej@sury.org>]

Hi,

I am searching for a solution for this scenario:

nsd3 (<= 4.0.0), e.g. from 3.2.x postrm script _remove_ "nsd" user
nsd3 (>= 4.0.0) is just a dummy package with hard depends on nsd (>=
4.0.0)
nsd (>= 4.0.0) creates "nsd" user in postinst and remove "nsd" user in
postrm

If nsd3 package is upgraded along nsd package then everything is good.

Now there's a rare situation where:

nsd3 3.2.x has been removed, but not purged (e.g. postrm hasn't been
run)
nsd 4.0.0 is installed
nsd3 3.2.x is purged

Now the "nsd" user has been removed in nsd3.postinst, but it is still
needed by nsd (>= 4.0.0) package. Any ideas how to fix that? Or should I
just cross the fingers and hope nobody would do such thing?

O.
-- 
Ondřej Surý <ondrej@sury.org>
Knot DNS (https://www.knot-dns.cz/) – a high-performance DNS server