feat(arx): add experimental macos support via fakedir

[cassandracomar]

fixes #17

see fakedir for limitations and caveats.

I've tested the nix bundle interface and am able to produce a working executable arx. I need to find a machine that doesn't have the /nix/store paths already loaded to do a final validation. I tested using ruby and I'm able to run basic ruby scripts. I'm going to continue testing with a more complicated application that makes use of native extensions next.

basic flake for testing:

{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-24.05";
    flake-utils.url = "github:numtide/flake-utils";
    nix-bundle.url = "github:cassandracomar/nix-bundle";
    bundlers = {
      url = "github:nixos/bundlers";
      inputs.nix-bundle.follows = "nix-bundle";
    };
  };

  outputs = {
    nixpkgs,
    flake-utils,
    nix-bundle,
    bundlers,
    ...
  }:
    flake-utils.lib.eachDefaultSystem (
      system: let
        pkgs = import nixpkgs {
          inherit system;
        };
      in {
        defaultBundler = bundlers.defaultBundler.${system};
      }
    );
}

use this flake as your bundler:

nix bundle --bundler path:/path/to/flake nixpkgs#app

once this PR merges and we're able to update the nix-bundle reference in nixos/bundlers, nix bundle should work out of the box on macos, with the caveat that fakedir has to be able to intercept the syscalls in use by your application.

[cassandracomar]

I added a patch to fix a null pointer dereference when ruby calls getcwd() (it passes a null destination buffer to getcwd(), which I'm not sure is totally sensible). I'll upstream the patch when I figure out what to do about the fact that this patch technically leaks the buffer.

I've also made it possible to run multiple executables within the same target package (in the same /bin directory). it uses argv0 to decide which binary to execute so symlink the bottle to the other binaries you want to reach and use symlinkJoin to produce a composite package with all the tools you need in one place.

lastly, because arx changes PWD and because fakedir can't set up a chroot with paths bind mounted into the right places, I added a way to restore PWD context, so bottled tools work just like a natively installed tool -- there's now a TMPX_RESTORE_PWD env var set by the tmpx script before calling the startup script that you can use to reset the PWD context after saving the TMPX unpack dir.

[HannesGitH]

unfortunately this does not work rn

➜  test git:(main) ✗ nix bundle --bundler . 'nixpkgs#hello' -L --show-trace
warning: not writing modified lock file of flake 'git+file:///Users/blingmember/Repos/bling_cli?dir=test':
• Added input 'bundlers':
    'github:nixos/bundlers/e3ea69055b77cc2b17c6ce4067b7e3bb01871245?narHash=sha256-eQyHKjL/u8w/9WiLfLtFPzqX0swn4VPqZMJ5/kKd3wc%3D' (2024-11-04)
• Added input 'bundlers/nix-bundle':
    follows 'nix-bundle'
• Added input 'bundlers/nix-utils':
    'github:juliosueiras-nix/nix-utils/b44e1ffd726aa03056db9df469efb497d8b9871b?narHash=sha256-9G8zo%2B0nfYAALV5umCyQR/2hVUFNH10JropBkyxZGGw%3D' (2021-09-30)
• Added input 'bundlers/nix-utils/flake-utils':
    'github:numtide/flake-utils/f7e004a55b120c02ecb6219596820fcd32ca8772?narHash=sha256-A8BU7bjS5GirpAUv4QA%2BQnJ4CceLHkcXdRp4xITDB0s%3D' (2021-06-16)
• Added input 'bundlers/nix-utils/nixpkgs':
    'github:nixos/nixpkgs/3788c68def67ca7949e0864c27638d484389363d?narHash=sha256-Aj20gmGBs8TG7pyaQqgbsqAQ6cB%2BTVuL18Pk3DPBxcQ%3D' (2021-08-18)
• Added input 'bundlers/nixpkgs':
    'github:NixOS/nixpkgs/5633bcff0c6162b9e4b5f1264264611e950c8ec7?narHash=sha256-9UTxR8eukdg%2BXZeHgxW5hQA9fIKHsKCdOIUycTryeVw%3D' (2024-10-09)
• Added input 'flake-utils':
    'github:numtide/flake-utils/11707dc2f618dd54ca8739b309ec4fc024de578b?narHash=sha256-l0KFg5HjrsfsO/JpG%2Br7fRrqm12kzFHyUHqHCVpMMbI%3D' (2024-11-13)
• Added input 'flake-utils/systems':
    'github:nix-systems/default/da67096a3b9bf56a91d16901293e51ba5b49a27e?narHash=sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768%3D' (2023-04-09)
• Added input 'nix-bundle':
    'github:cassandracomar/nix-bundle/30c2ad34a5999251e9f08c157e0bd3c4d372a889?narHash=sha256-7BH4TvfSLy4NHMjS4xUbXFDtqq7lmcKNgL6MdaspGFg%3D' (2024-09-17)
• Added input 'nix-bundle/fakedir-pkgs':
    'github:nixie-dev/fakedir/a2bd8d0eb974bcbfbc4963e7c61a7162968cee6b?narHash=sha256-krWOwpqjg83Y5e9ly8IJ81icqH4YUNbkIIW1jqiaYhY%3D' (2024-08-12)
• Added input 'nix-bundle/fakedir-pkgs/nixpkgs':
    'github:NixOS/nixpkgs/d412d7956754408c347291516d1d3e3ea469642b?narHash=sha256-WlJapOhp/D/r8SjajToSBsrX9r0%2BjeKmZ6C8OZ3BJ94%3D' (2023-02-21)
• Added input 'nix-bundle/fakedir-pkgs/utils':
    'github:numtide/flake-utils/3db36a8b464d0c4532ba1c7dda728f4576d6d073?narHash=sha256-XX2f9c3iySLCw54rJ/CZs%2BZK6IQy7GXNY4nSOyu2QG4%3D' (2023-02-13)
• Added input 'nix-bundle/nixpkgs':
    'github:NixOS/nixpkgs/7cec143201c32c4937f2c153af4a9f28a3d9bec1?narHash=sha256-bFOTvmkJ2c1ku%2BE0gvqmNEF2D1PSmujDFLofKAMF/pM%3D' (2024-08-07)
• Added input 'nixpkgs':
    'github:nixos/nixpkgs/b134951a4c9f3c995fd7be05f3243f8ecd65d798?narHash=sha256-OnSAY7XDSx7CtDoqNh8jwVwh4xNL/2HaJxGjryLWzX8%3D' (2024-12-30)
error:
       … while evaluating the attribute 'defaultBundler'
         at /nix/store/5f8nydan34q0r5y59dyrx0cxz1p0d1p1-source/test/flake.nix:25:9:
           24|       in {
           25|         defaultBundler = bundlers.defaultBundler.${system};
             |         ^
           26|       }

       error: attribute 'defaultBundler' missing
       at /nix/store/5f8nydan34q0r5y59dyrx0cxz1p0d1p1-source/test/flake.nix:25:26:
           24|       in {
           25|         defaultBundler = bundlers.defaultBundler.${system};
             |                          ^
           26|       }

swapping defaultBundler = bundlers.defaultBundler.${system}; for defaultBundler = bundlers.bundlers.${system}.default; doesnt help either and results in

error:
      … while evaluating the attribute 'defaultBundler'
        at /nix/store/vh9xpn2ald80s4asxwpwj2kcq0d7hq97-source/test/flake.nix:25:9:
          24|       in {
          25|         defaultBundler = bundlers.bundlers.${system}.default;
            |         ^
          26|       }

      … while evaluating the attribute 'bundlers.aarch64-darwin.default'
        at /nix/store/1gyz5qxc7gqzabf2ds6rz2h86s3qzb8p-source/flake.nix:47:7:
          46|
          47|       default = toArx;
            |       ^
          48|       toArx = nix-bundle.bundlers.${system}.nix-bundle;

      … while evaluating the attribute 'bundlers.aarch64-darwin.nix-bundle'
        at /nix/store/6mjljsdwws9cwwkznvi0q8wzfl5pxgr0-source/flake.nix:8:5:
           7|   outputs = { self, nixpkgs, fakedir-pkgs }: {
           8|     bundlers = {
            |     ^
           9|       nix-bundle = { program, system }: let

      error: attribute 'aarch64-darwin' missing
      at /nix/store/1gyz5qxc7gqzabf2ds6rz2h86s3qzb8p-source/flake.nix:48:15:
          47|       default = toArx;
          48|       toArx = nix-bundle.bundlers.${system}.nix-bundle;
            |               ^
          49|

[HannesGitH]

@cassandracomar if you could help me fix this seemingly small problem, i can check if the bundled executable runs on macs without nix installed

[cassandracomar]

can you post your flake? want to compare with the testing I've done.

[HannesGitH]

Thanks for the response!

for that error reproduction I used the exact flake you provided :) but it probably got locked to newer nixpkgs, bundlers thats why i provided that output as well

[cassandracomar]

hmm, I'll see this weekend if I can figure out what's changed upstream.

[HannesGitH]

any progess?

[woile]

This looks awesome! Having something like this would make it very easy to distribute a nix derivation for MacOS users who don't have nix installed 🙌🏻

[Eveeifyeve]

Is this pr abandoned? Or are you still working on it because if you are I highly suggest resolving the conflicts and making this a draft. Because I might have a go at trying to get it to work, if it’s abandoned it’s a high priority as a business at DigitalBrewStudios.

[HannesGitH]

@Eveeifyeve I aint the author, but It feels quite abandoned, so I'd guess you can have a go

[Eveeifyeve]

I will give the person at least a business day to respond. If they don't this Friday as part of our office hours at DigitalBrewStudios I am going to takkle it with them added as co-author.