TODO: pin to specific (working) nixpkgs revision about nixpkgs-mozilla HOT 5 OPEN

Finally got it working. I don't know if there is something wrong with my nix installation or there were simply some braces missing from your blog post, but the following works for me:

{ nixpkgs ? (import ( _nixpkgs.fetchFromGitHub { 
owner = "NixOS"; 
repo = "nixpkgs"; 
rev = "..."; 
sha256 = "..."; }){})}:

Whereas the original solution does not:

{ nixpkgs ? (import _nixpkgs.fetchFromGitHub { 
owner = "NixOS"; 
repo = "nixpkgs"; 
rev = ...; 
sha256 = ...; })}:

I don't know enough nix, but wouldn't something like the following be great to have? Can't we add such behaviour to import itself?

{nixpkgs ? import <nixpkgs> { rev = "..."; sha256 = "..."; }  }:
...

from nixpkgs-mozilla.

Hm. The part where we set the nix path still does not work with this solution:

nix-shell --arg nixpkgs /absolute/path/to/nixpkgs.

from nixpkgs-mozilla.

Ok. Finally got something working:

{nixpkgs ? null}:
let
  sysPkg = import <nixpkgs> { };
  pinnedPkg = sysPkg.fetchFromGitHub {
    owner = "NixOS";
    repo = "nixpkgs";
    rev = "cf62a27a326a9cdbb01d627b1faaea3a0d5e886c";
    sha256 = "1q74ciqq5r17vidw2025x8idsncz9k7w60warrij4q7piaffgvd7";
  };
  pkgs = if nixpkgs==null then
           import pinnedPkg {}
         else
           import nixpkgs {};
in with pkgs; stdenv.mkDerivation rec {
  name = "ProjectA-1.0.0";
  src = ./.;
  buildInputs = [ pkgs.python ];
  installPhase= ''
    sed -i -e "s|python|`which python`" bin/serve
    mkdir -p $out/bin
    cp bin/* $out/bin
  '';
}

from nixpkgs-mozilla.

Looks right to me. I don't know if we can reduce this further.

My only suggestion would be to name it mozpkgs or anything else than nixpkgs since that term is already referencing the nixos/nixpkgs repo.

from nixpkgs-mozilla.

You guys may also be interested in my technique for fully deterministic bootstrapping of a nixpkgs pin. It makes no assumptions other than that your Nix interpreter implements a superset of the semantics implemented by Nix 1.11.8 (which seems likely to be true into the forseeable future). In the future, when Nix 1.12 comes out, fetchTarball will support a sha256 argument, and this hack can be replaced with fetchTarball (if you try to use fetchTarball now, it will redownload every time the cache expires, which can be very annoying).

from nixpkgs-mozilla.