Private packages cannot be fetched using `pkgs.fetchgit`

I've some private packages in my packages.dhall with the following repo:

{
  # ...
  , repo = "ssh://git@github.com/my-org/my-repo.git"
  , version = "<rev>";
}

spago2nix generate gives me derivations with srcs looking like:

src = pkgs.fetchgit {
  url = "https://github.com/my-org/my-repo.git";
  rev = "<rev>";
  sha256 = "<hash>";
}

But pkgs.fetchgit cannot download private repos. My solution was to create a wrapped-spago-packages.nix that wraps the automatically generated spago-pacakges.nix using builtins.fetchGit instead of pkgs.fetchgit for predefined list of repos i.e. the private repos.

# wrapped-spago-packages.nix
{ pkgs }:
let
  patchedPkgs = pkgs // {
    fetchgit = args:
      let
        regex = ".*/(.*)/([^.]*).*";
        matches = builtins.match regex args.url;
        owner = builtins.elemAt matches 0;
        repo = builtins.elemAt matches 1;
        condition = owner == "my-org" && builtins.elem repo [
          "my-repo"
        ];
      in
      if condition then
        builtins.fetchGit
          {
            inherit (args) rev;
            url = "ssh://git@github.com/${owner}/${repo}.git";
          }
      else pkgs.fetchgit args;
  };
in
import ./spago-packages.nix { pkgs = patchedPkgs; }

And then, wherever I was using ./spago-packages.nix I use ./wrapped-spago-packages.nix instead.

Said this, one obvious solution would be directly generating ./spago-packages.nix using builtins.fetchGit instead of pkgs.fetchgit but I'm not sure about consequences. As far as I know builtins.fetchGit doesn't return a derivation but directly a path, that means that the fetching is done at eval time and fetching all of this stuff at eval time could be a not good thing. Perhaps there should be an spago2nix's argument to let people choose what they want to do?

@justinwoo If you agree about this and you want to give me clear directives i would be happy to open a PR.

justinwoo / spago2nix

Private packages cannot be fetched using `pkgs.fetchgit` #54