nixFlakes fails to build on aarch64-darwin

[purcell]

Describe the bug

nixFlakes doesn't build on this system type, which then blocks other dependent tools from building, e.g. the nix-direnv module integration.

To Reproduce

Steps to reproduce the behavior:

1. On an M1 machine using the nixpkgs-unstable channel, check out nixpkgs master (currently 976ee28 for me)
2. nix-build --argstr localSystem aarch64-darwin -A nixFlakes

Expected behavior

Successful build.

Screenshots

  CXX    src/resolve-system-dependencies/resolve-system-dependencies.o
  GEN    scripts/nix-http-export.cgi
  CXX    src/libcmd/markdown.o
  GEN    scripts/nix-profile.sh
  GEN    scripts/nix-reduce-build
  GEN    doc/manual/nix-env.1
lowdown: sandbox_init: Operation not permitted
make: *** [doc/manual/local.mk:28: doc/manual/nix-env.1] Error 1
make: *** Waiting for unfinished jobs....
builder for '/nix/store/pv51gkfqicxdib8c26plmjg7mphknnbz-nix-2.4pre20210503_6d2553a.drv' failed with exit code 2

Additional context
Add any other context about the problem here.

Notify maintainers

Metadata
Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
  - nixFlakes
# a list of nixos modules affected by the problem
module:

[purcell]

Maybe @thefloweringash has encountered this in all his amazing recent work? ❤️

[hlolli]

nixFlakes = nixUnstable;

nixpkgs/pkgs/top-level/aliases.nix

Line 498 in d3bc4f9

nixFlakes = nixUnstable; # added 2021-05-21

Maybe this ticket has a better home in https://github.com/NixOS/nix ?

the nixUnstable also seems to be targeting few months old revision (20th march 2021?)

nixpkgs/pkgs/tools/package-management/nix/default.nix

Lines 208 to 211 in 7a2a683

	nixUnstable = lib.lowPrio (callPackage common rec {
	pname = "nix";
	version = "2.4${suffix}";
	suffix = "pre20210503_6d2553a";

[hlolli]

4wiw I'm testing now

let nixUnstableSrc = pkgs.fetchFromGitHub {
      owner = "NixOS";
      repo = "nix";
      rev = "b10256af51dfa929e8f916414d6f021dd45f2e1e";
      sha256 = "sha256:1r6d5y17v5v8mmjva82vgybvhg0s8024qns8irwnbnrbb5nxszgd";
    };
in {
  nixpkgs.overlays = [
    (
    self: super: {
      nixUnstable = super.nixUnstable.overrideAttrs (o: {
        src = nixUnstableSrc;
        patchPhase = "true";
        buildInputs = o.buildInputs ++ [ super.nlohmann_json ];
      });
      nix = super.nixUnstable.overrideAttrs (o: {
        src = nixUnstableSrc;
        patchPhase = "true";
        buildInputs = o.buildInputs ++ [ super.nlohmann_json ];
      });
    }
  )];
}

it worked for x86_64, trying now aarch64

[hlolli]

The attempt above failed because:

1. nix uses mdbook which uses pandoc uses haskell which isn't portable to aarch64 yet. (this overlay hack solved it pandoc = pkgs.writeShellScriptBin "pandoc" "echo true"; )
2. lowdown runtime fails with aarch64

I tried passing x86_64 only for the lowdown binary

patchPhase = ''
          substituteInPlace doc/manual/local.mk \
            --replace lowdown ${pkgsX86.lowdown}/bin/lowdown
        '';

but later in the build, the os will want to open rosetta when the binary is called

 > libc++abi: terminating with uncaught exception of type nix::SysError: error: getting status of /Library/Apple/System/Library/LaunchDaemons/com.apple.oahd.plist: Operation not permitted
       > /nix/store/yz0alyb7mfvqs085p0m8nf808ds27c32-bash-4.4-p23/bin/bash: line 1: 43039 Abort trap: 6           env -i HOME=/dummy NIX_CONF_DIR=/dummy NIX_SSL_CERT_FILE=/dummy/no-ca-bundle.crt NIX_STATE_DIR=/dummy /nix/store/5lhgr8lg29slxjmag3lpgc274q7rclqp-nix-2.4pre20210503_6d2553a/bin/nix show-config --json --experimental-features nix-command > doc/manual/conf-file.json.tmp
       > make: *** [doc/manual/local.mk:61: doc/manual/conf-file.json] Error 134

[purcell]

Argh. Thanks for writing up what you've discovered!

[hlolli]

So it's a bootstraping issue in a sense, with the fix here #125004 I removed all docs build and all check (from both pkgs/tools/package-management/nix/default.nix and nix repo itself), built, then I had arm64 binary of nix, then I reverted all the changes, built again, then it built fine. It seems undo-able to build arm64 binaries in general using x86_64, for now.

[domenkozar]

NixOS/nix#4334