Gap between rolling-release branch and static commit hash

[ryuheechul]

Moving a conversation over to this issue for better tracking.

@ryuheechul
(commenting at specific line)
rolling release, but old commit? I'm new to niv today and I was expecting a latest commit but discovered that it's actually not after looking up the commit. (since it's nixos-unstable, expectations might be set to the latest commit instead of an fixed old commit)

this can be mitigated by manually running niv update nixpkgs but it would be nice that the latest commit is being used by default.

@nmattia
I think we used to do that, but that means checking out nixpkgs (slow) and computing its hash. Maybe there's a list of nixpkgs commits & hashes somewhere?

@ryuheechul
I see, I can see that there is a virtue of simplicity when working with static data.
In that case, maybe informing about it (the commit hash is static therefore user might want to update themselves) would be nice on top of the current existing message when niv init

$ niv init
Initializing
  Creating nix/sources.nix
  Creating nix/sources.json
  Using known 'nixpkgs' ...
  Adding package nixpkgs
    Writing new sources file
  Done: Adding package nixpkgs
Done: Initializing

# my one suggested example here
A heads up! `niv init` didn't fetch the latest commit for nixpkgs.
Run `niv update nixpkgs` if you wish to follow the latest.

@nmattia
good point. Do you want to create a ticket? It'll be easier to track