pcsx2: darwin support, add maintainer

[matteo-pacini]

Description of changes

• Split the package in linux.nix and darwin.nix
• darwin.nix fetches the pre-compiled binaries from GitHub
  • Tried to compile this but fails on aarch64-darwin, requires a x86_64-darwin machine
  • Cannot be compiled also as Xcode is needed to build Metal shaders
  • The pre-compiled app runs fine under Rosetta, the version is in sync with the Linux one
• The three files have been formatted with nixfmt-rfc-style.
• Added myself as maintainer for Darwin

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/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 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.

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[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-ready-for-review/3032/4127

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-ready-for-review/3032/4132

[afh]

Result of nixpkgs-review pr 320122 run on aarch64-darwin 1

1 package built:

• pcsx2

[afh]

Nicely done, @matteo-pacini, please find below some hopefully helpful comments for potential future improvement…

[afh]

❓ What are your thoughts around adding support to build this package on x86_64-darwin instead of installing the pre-built binary from upstream?

[matteo-pacini]

@afh Imho, It would make this package harder to maintain - I would make it compile from source only if it's supported on both aarch64-darwin and x86_64-darwin.

I also expect x86_64-darwin to slowly lose traction and disappear, so any effort towards that architecture could potentially become a waste of maintainers' time.

This is just my personal opinion, and up to debate: I expect plenty of new Nix adopter to be on aarch64-darwin, rather than x86_64-darwin.

[emilazy]

It might be worth reconsidering this in light of the upcoming Apple Silicon support?

[afh]

That makes sense, @matteo-pacini, I'm alright with this being x86_64-darwin until Apple Silicon supports lands upstream and this can be built from source.

[afh]

The app requires Rosetta to run, how could this dependency be declared in nixpkgs in general to differentiate between packages that run natively on Apple Silicon and packages needing Rosetta?

[matteo-pacini]

@afh That's a good point - my gut tells me this should only be declared as a x86_64-darwin derivation, and then aarch64-darwin can download this anyway by using Nix config / extra platforms.

@NixOS/darwin-maintainers thoughts on this?

[SuperSamus]

FYI, upstream is working on natively supporting ARM.
https://github.com/PCSX2/pcsx2/pull/11364

[emilazy]

That's a good point - my gut tells me this should only be declared as a x86_64-darwin derivation, and then aarch64-darwin can download this anyway by using Nix config / extra platforms.

I agree. There’s nothing about this app that is aarch64-darwin (currently); it just so happens that all aarch64-darwin machines support software that lets them run x86_64-darwin software.

[matteo-pacini]

@SuperSamus @afh @emilazy Thanks for the feedback, I'm going to change the derivation and make it natively compile for x86_64-darwin, so it's ready for when aarch64-darwin support will be officially released.

[afh]

Thanks everyone for chiming in on this, very helpful 🙏

@matteo-pacini please find below updated comments 🙂

[afh]

Given the latest comments as this PR stands now I kindly request the following change:

Suggested change

	platforms = [ "x86_64-linux" ] ++ platforms.darwin;
	platforms = [ "x86_64-linux" "x86_64-darwin" ];

[afh]

That makes sense, @matteo-pacini, I'm alright with this being x86_64-darwin until Apple Silicon supports lands upstream and this can be built from source.

[matteo-pacini]

@emilazy I've encountered a roadblock, the build fails when trying to compile Metal shaders, as that would require host's tools, Xcode and xcrun.

What's the best / ideal way forward here? Here's four potential approaches:

1. Expose hosts tool. Using tools on the host would be tricky, i.e. it will depend on the host having Xcode installed - lot of impurity.
2. Patching the app so the shaders are not compiled, just copied over, but then I would have to change the Metal pipeline, so those are compiled at runtime instead. Not impossible but this would be highly time consuming. Also we don't know for how long this will work and might require constant maintenance over time.
3. Fetch the binary dist from Github regardless, and copy over the pre-compiled *.metallib files to the final app bundle - not ideal, but it should work.
4. We could just stick to the binary distribution as a temporary solution, and think how to bring Metal shader compiling into the packaging pipeline, so other derivations can benefit from it too, and revisit this at a later stage.

Pinging also @NixOS/darwin-maintainers, any advice would be greatly appreciated.

[matteo-pacini]

@emilazy @afh reverted this PR to its previous state.

As stated in #320122 (comment), some thinking is required to bring Metal shaders into the pipeline.
I don't thinks there's an immediate / obvious solution to this, so I suggest to go with option (4) from the previous comment, rather than having no Darwin support at all.

I'll bring this topic up on Matrix when I got some time 👍🏻

[afh]

I agree with you, @matteo-pacini.

Would you be interested in setting up a draft PR for the native darwin build that also tracks the development of Apple silicon in upstream? Might be helpful to get folks together and advise on best paths forward in regards to xcrun and Xcode…

[afh]

🙂👍

[toonn]

LGTM