As a reminder, plumbing is not my strongpoint but I do it pretty much
without leaks pretty much first shot lately.

Anyway, Under a sink, black (ABS?) to white (PVC) seems to be a no-no. From
what I take, it's the gluing that is the issue. Actually I hear Oatey makes
an acceptable glue now. Local codes often don't accept this I also hear.

My Q is not about gluing though. It at the slip joints. Since there is no
glue involved, does general code allow this? And again, of course local
code prevails.