[Nix-dev] [haskell] [travis] building takes more than 50 minutes

[Peter Simons]

Hi Dmitry,

 > After all that I have a strong feeling that most of these Haskell packages
 > could have been used from some binary sources (or from channels) and there
 > were no need to compile them.

the situation will improve once the nixos-unstable channel updates [1]. At the
moment, cache.nixos.org doesn't contain any Haskell libraries, but commit
c5d132c2ea has changed that (or so I hope). It just hasn't reached the channel
yet.

Also, it's my understanding that "matrix builds" on Travis-CI actually run on
separate virtual machines. Is that correct? If that is so, then building with
3 versions of GHC that way means installing and downloading the Nix environment
3 times for every commit, too, which seems rather wasteful.

Best regards,
Peter


[1] https://github.com/NixOS/nixpkgs/issues/8057