ruby-modules: improve cross-compilation support

[tie]

Description of changes

This PR contains fixes for cross-compilation in Ruby infrastructure. In particular,

• bundler{App,Env} were using host ruby to execute gen-bin-stubs.rb, same for rsync if copyGemFiles was set.
• buildRubyGem output contained Ruby-generated binstubs that referenced ruby from nativeBuildInputs.

For example,

nix build --impure --expr 'let
  pkgs = import ./. {
    localSystem.system = "aarch64-linux";
    crossSystem.config = "x86_64-unknown-linux-gnu";
  };
in
pkgs.doing'

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

Priorities

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[tie]

I’m really confused here, is this PR somehow blocklisted? Is Ruby ecosystem so dead that we don’t review changes anymore (e.g. #258705 also took a long time to merge)? Am I the only one actually using it (given that nobody complained about this issue before)? Do I have to sell my soul to the devil to get this PR reviewed? It’s been 6 months (that’s a full NixOS release cycle) with zero feedback from maintainers and requested reviewers. 😢

[anthonyroussel]

@tie Hello!

Sorry for the late reply, and thank you for your work on improving cross-compilation support for Ruby packages 😄

Your changes looks good to me, but unfortunately I don't have a computer powerful enough to test your changes (cross-compilation + ~2500 rebuilds) and check that everything's OK on my end.

As your PR targets the staging branch, I think we can merge and check that the builds are OK on Hydra during the next staging-next cycle?

[tie]

Thank you, yes, that sounds good.

[anthonyroussel]

@ofborg build pkgsCross.gnu64.bundler pkgsCross.gnu64.puppet-bolt

[tie]

I’m not really sure if puppet-bolt is a good test case without #316023.

Edit: yes, it doesn’t build without this PR, but does with 9b73495 cherry-picked (pkgsCross.gnu64 from aarch64-linux).

[SuperSandro2000]

Those changes are pretty simple and just correct that we use the correct binaries in shebangs, nothing compiler/linker related. I think we can safely merge this.

[github-actions]

Successfully created backport PR for staging-24.05:

• [Backport staging-24.05] ruby-modules: improve cross-compilation support #322506

[trofi]

Bisect says 3097117 ruby-modules: improve cross-compilation support broek weechat build in staging:

$ nix build --no-link -f. weechat -L
...
weechat> [ 53%] Built target doc-quickstart-pl
weechat> [ 53%] Built target doc-quickstart-ru
weechat> No such file or directory - /nix/store/m15q42klamlbf7czyk1bscjfnwsjr2ay-ruby3.1-pygments.rb-2.4.0/lib/ruby/gems/3.1.0/gems/pygments.rb-2.4.0/lib/pygments/mentos.py
weechat>   Use --trace to show backtrace

[trofi]

Probably due to unpatched shebang in the store:

$ head -n1 /nix/store/m15q42klamlbf7czyk1bscjfnwsjr2ay-ruby3.1-pygments.rb-2.4.0/lib/ruby/gems/3.1.0/gems/pygments.rb-2.4.0/lib/pygments/mentos.py
#!/usr/bin/env python3