Bug#1092164: apt: SRV query not performed without netbase installed

[Chris Hofstaedtler <zeha@debian.org>]

Package: apt
Version: 2.6.1

For a while I've been seeing odd behaviour where apt ignored the SRV
DNS records we inject to redirect deb.debian.org elsewhere (to a local
cache, so the entire network benefits without any local setup).

Debugging shows that only a single deb.debian.org A DNS query is
performed, and no SRV queries are performed. Googling this yielded
https://gist.github.com/tsangwpx/fd3c5c2b9aac53d9d0964cf3dc91b2ed .
Apparently this is known behaviour to some people on the internet,
but was news to me.

Here is a minimal reproducer:

  $ podman run -it --rm debian:bookworm-slim bash
  # apt update

This will use an A lookup, and thus ignore SRV.

This however works:

  $ podman run -it --rm debian:bookworm-slim bash
  # echo http 80/tcp > /etc/services
  # apt update

Could this please be made work by default in the common container
scenario? So probably without having netbase (provides
/etc/services) installed?

Thanks,
Chris