Error: attribute 'stdenvNoCC' missing inside of flake, but not in repl

Hello dear nix community, I’m trying to package dotnet project into flake and I’m hitting the wall with nix code giving me error in the flake, but not in repl.

Here is my code:
loadfromlock.nix

{
  # tried to use pkgs and resolve dependices in this file but it had the same error
  # pkgs ? import <nixpkgs> {}, 
  stdenvNoCC, lib, fetchurl, unzip,
  filepath
}:
let
  lock = import ./readlock.nix {inherit  lib; filepath = filepath; };
  fetchNuget = import ./fetchnuget.nix { inherit stdenvNoCC lib fetchurl unzip; };
in
  map(package: fetchNuget { pname = package.name; version = package.version; hash = package.contentHash; }) lock

in the flake I have

{
  description = "My dotnet flake";
  outputs = inputs@{
    self,
    nixpkgs,
    ... }:
  let
       ...
      nugets = import ./loadfromlock.nix { inherit (nixpkgs) stdenvNoCC lib fetchurl unzip; filepath = filepath;};
  in {
   ...
     }

which results in

error: attribute 'stdenvNoCC' missing

       at /nix/store/yy9yjds5cwzc8hglsxrclrpa33jgs4xg-source/flake.nix:54:43:

           53|       filepath = ./packages.nixlock.json;
           54|       nugets = import ./loadfromlock.nix { inherit (nixpkgs) stdenvNoCC lib fetchurl unzip; filepath = filepath;};
             |                                           ^
           55|   in {

       … while evaluating anonymous lambda

       at /nix/store/yy9yjds5cwzc8hglsxrclrpa33jgs4xg-source/fetchnuget.nix:3:1:

            2| {stdenvNoCC, lib, fetchurl, unzip}:
            3| attrs@{
             | ^
            4|     pname,

       … from call site

       at /nix/store/yy9yjds5cwzc8hglsxrclrpa33jgs4xg-source/loadfromlock.nix:10:16:

            9| in
           10|   map(package: fetchNuget { pname = package.name; version = package.version; hash = package.contentHash; }) lock
             |                ^

       … while evaluating anonymous lambda

       at /nix/store/yy9yjds5cwzc8hglsxrclrpa33jgs4xg-source/loadfromlock.nix:10:7:

            9| in
           10|   map(package: fetchNuget { pname = package.name; version = package.version; hash = package.contentHash; }) lock
             |       ^

       … from call site

       … while evaluating 'isDerivation'

       at /nix/store/kc7nh9sdr4z8c7xc9j9891v212k2zj8k-source/lib/attrsets.nix:427:18:

          426|   */
          427|   isDerivation = x: x.type or null == "derivation";
             |                  ^
          428|

       … from call site

       at /nix/store/kc7nh9sdr4z8c7xc9j9891v212k2zj8k-source/pkgs/stdenv/generic/make-derivation.nix:193:8:

          192|   checkDependencyList' = positions: name: deps: lib.flip lib.imap1 deps (index: dep:
          193|     if lib.isDerivation dep || isNull dep || builtins.typeOf dep == "string" || builtins.typeOf dep == "path" then dep
             |        ^
          194|     else if lib.isList dep then checkDependencyList' ([index] ++ positions) name dep

       … while evaluating anonymous lambda

       at /nix/store/kc7nh9sdr4z8c7xc9j9891v212k2zj8k-source/pkgs/stdenv/generic/make-derivation.nix:192:81:

          191|   checkDependencyList = checkDependencyList' [];
          192|   checkDependencyList' = positions: name: deps: lib.flip lib.imap1 deps (index: dep:
             |                                                                                 ^
          193|     if lib.isDerivation dep || isNull dep || builtins.typeOf dep == "string" || builtins.typeOf dep == "path" then dep

       … from call site

       at /nix/store/kc7nh9sdr4z8c7xc9j9891v212k2zj8k-source/lib/lists.nix:117:32:

          116|   */
          117|   imap1 = f: list: genList (n: f (n + 1) (elemAt list n)) (length list);
             |                                ^
          118|

       … while evaluating anonymous lambda

       at /nix/store/kc7nh9sdr4z8c7xc9j9891v212k2zj8k-source/lib/lists.nix:117:29:

          116|   */
          117|   imap1 = f: list: genList (n: f (n + 1) (elemAt list n)) (length list);
             |                             ^
          118|

       … from call site

       … while evaluating the attribute 'buildInputs' of the derivation 'altair-20220815-dirty'

       at /nix/store/kc7nh9sdr4z8c7xc9j9891v212k2zj8k-source/pkgs/stdenv/generic/make-derivation.nix:270:7:

          269|     // (lib.optionalAttrs (attrs ? name || (attrs ? pname && attrs ? version)) {
          270|       name =
             |       ^
          271|         let

but in if run the same loadfromlock.nix in repl I would get desired result as such

Welcome to Nix 2.10.3. Type :? for help.
nix-repl> nixpkgs = import <nixpkgs> {}
nix-repl> filepath = ./packages.nixlock.json
nix-repl> nugets = import ./loadfromlock.nix { inherit (nixpkgs) stdenvNoCC lib fetchurl unzip; file
path = filepath;}
nix-repl> nugets
[ «derivation /nix/store/h7p37plmcg9hczk2h5jc0s7m0lg92kmy-nuget-GitVersion.MsBuild-5.7.0.nupkg.drv» «derivation /nix/store/4xswdi1famd03zrgj7wfa0dqcg15zyh5-nuget-StyleCop.Analyzers-1.1.118.nupkg.drv» ]

What am I missing here?

nixpkgs here is not the same thing as import <nixpkgs> {}. It’s the flake outputs of the nixpkgs flake. If you want stdenvNoCC, you need to look for it in nixpkgs.legacyPackages.${system}.stdenvNoCC. Or you could do import nixpkgs { system = ...; }, which will ignore the flake outputs and import the default.nix as normal. You have to provide system though, as it’s not allowed to use builtins.currentSystem when evaluating in pure mode.

2 Likes

That was my guess since I couldn’t use it with :lf nixpkgs in repl. Thank you that is very helpful.

My flake actually already had a second version of your answer, but it was in the form a loop function (not sure what is the appropriate language here) for multiple system inputs borrowed from rust template, so I followed along and embraced it as such


     nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system ; overlays = [ self.overlay.${system} ];});
     filepath = ./packages.nixlock.json;
     nugets = system: import ./loadfromlock.nix { inherit (nixpkgsFor.${system}) stdenvNoCC fetchurl unzip lib;  filepath = filepath;};
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