[Nix-dev] creating a channel as an extension of the nixos channel, not a replacement

[Mathijs Kwik]

Hi all,

I would like to create my own channel.
As the packages in my channel depend on packages from the nixos
channel, nix-push ends up creating a lot of narballs that are
available in nixos itself.
In a way, this is nice, because it gives me a fully self-contained
archive of everything I use.
But it takes up a lot of space and transferring it takes a lot of time too.

Is it possible to tell nix-push to ignore packages that are already
available in the nixos channel?
Changing the "ArchivesGetURL" to check nixos might be an option, but
of course then it won't be able to check availability of my own
packages. I couldn't find a way to say "check multiple sources".
Another way is to setup some smart cgi script on the GetUrl of my
channel that checks nixos in the background before replying.

But I would like to know if this is really meant to

Is there a way to do this? Or are channels just designed to be
monolithic and self-contained without inter-channel dependencies at
the moment?

Thanks and have a nice weekend,
Mathijs