Crosscompilation issue: package samba:armhf has unmet dependencies: python-dnspython

Hi,

I’m trying to crosscompile a snap for samba, but it fails with unmet dependencies to python-dnspython.

I am using a custom plugin based on nil to be able to use my sources.list that includes

deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial main restricted
deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted
deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial universe
deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial-updates universe
deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial multiverse
deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb [arch=amd64] http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
deb [arch=amd64] http://security.ubuntu.com/ubuntu/ xenial-security main restricted
deb [arch=amd64] http://security.ubuntu.com/ubuntu/ xenial-security universe
deb [arch=amd64] http://security.ubuntu.com/ubuntu/ xenial-security multiverse

deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial main restricted
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-updates main restricted
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial universe
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-updates universe
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial multiverse
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-updates multiverse
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-backports main restricted universe multiverse
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-security main restricted
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-security universe
deb [arch=armhf,arm64] http://ports.ubuntu.com/ubuntu-ports/ xenial-security multiverse

My snapcraft.yaml:

name: my-samba
version: git
summary: Add support for Samba
description: Samba support (Windows share)
grade: devel
confinement: devmode

apps:
  samba:
    command: bin/bash -c $SNAP/usr/local/bin/samba.sh
    plugs: [ network, network-bind ]
    daemon: simple
    restart-condition: always

parts:
  samba:
    plugin: nil_src
    stage-packages:
      - on amd64 to armhf: [ "bash:armhf", "samba:armhf" ]
      - else: [ bash, samba ]

  config:
    plugin: dump
    source: snap/local
    prime:
      - etc
      - usr

My issue is that the package python-dnspython is part of all architecture and is not found in armhf.

Any ideas on how would I go about to solve the dependency chain?

Regards,

Daniel