Swift 6 coming soon?

Pierre-Thibault · November 3, 2024, 6:06pm

Is anyone doing development with Swift?

When are we going to have Swift 6?

Carrot · November 3, 2024, 6:35pm

github.com/NixOS/nixpkgs

Update request: swift 5.8 → 6

opened 08:36AM - 20 Sep 24 UTC

b521f771d8991e6f1d8e65ae05a8d783

9.needs: package (update)

- Package name: swift - Latest released version: 6 - [x ] Checked the [nixpkgs… pull requests](https://github.com/NixOS/nixpkgs/pulls) **Notify maintainers** @dtzWill @trepetti @dduan @Trundle @stephank ----- Note for maintainers: Please tag this issue in your PR. --- Add a :+1: [reaction] to [issues you find important]. [reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/ [issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc https://www.swift.org/install/linux/debian/12/#versions Swift also supports a static SDK now, it would be truly great to also have support for that. After trying to update the package myself, I wonder if package updates were not simpler if we would just use the official swift build process instead of hacking together our own. The current version is hopelessly behind the official, with the release of cross-compiling targets such as the static SDK and WASM, which are both highly relevant, it would seem prudent to re-evaluate if `utils/update-checkout` and `utils/build-script` would not simplfy the process to a great extent.

emily · November 3, 2024, 8:27pm

Swift needs serious clean‐up, potentially a full rewrite, and solving the mysterious Hydra build issues. There are a couple of people who have expressed interest in doing so for 25.05 in the Nix on macOS Matrix room and I’d like to assist such efforts, which should be easier now that Randy’s macOS SDK rework is in.

The plan would ideally be to update to 5.10, the last version that can be bootstrapped without an existing Swift compiler, and then use that to build Swift 6. If you’re interested in helping out then come say hi on Matrix!

Pierre-Thibault · November 3, 2024, 8:51pm

What qualifications would be needed to be helpful in this mission?

emily · November 4, 2024, 6:33am

Knowing things about the Swift build system would be a big help! Experience with Nix packaging would also of course be necessary, and we’d want to make modifications to the existing LLVM package infrastructure to accommodate Swift’s fork. However we already have lots of people with extensive experience with Nixpkgs and LLVM and relatively few with interest and knowledge of the Swift compiler and its build system and bootstrap process, so that’s the skill that would help the effort most on the margin.

Pierre-Thibault · November 5, 2024, 3:00pm

I guess I am not there yet.

reckenrode · November 5, 2024, 4:01pm

Another way one could help is by having a body of Swift code that can be tested with the packaged compiler. If Swift support is going to be reworked, it’s an opportunity to improve things for Swift users.

welkinSL · April 22, 2025, 6:39am

I did a quick search and it seems there aren’t much swift project available in nixpkgs.

If my pull request got merged then then mas package can be tested on:

github.com/NixOS/nixpkgs

Refactor mas package + update from 1.9.0 release -> 2.1.0 release

NixOS:master ← ed9w2in6:mas-2.1.0

opened 06:01AM - 22 Apr 25 UTC

ed9w2in6

+247 -55

## Default When build by default, the previous and this new version would yield identical `mas` binaries. ## New features Created two new version to allow **optionally to build from source**: - mas-from-src.nix - mas-from-release.nix Both version additionally installs **shell completions from official repository**. Both provides additional **option to fix up the swift dylib**. This is because Apple stop distributing them natively to old version macOS that they drop support. This option simplifies it. https://github.com/mas-cli/mas/issues/777 version, repoRev, repoSrc, releaseSrc are made overridable too. ### Source build method In order to build from source, I add included a patch `create_source_mas_package_dot_swift.patch` into `nixpkgs` because source build logic relies on a code generation script on build time. By mimic that script with a patch, it is easier to detect overwrites than a manual `patchPhase`, easier to maintain in the long run. ## Conflicts Conflicts with pull request https://github.com/NixOS/nixpkgs/pull/398976 ## Things done - Built on platform(s) - [ ] x86_64-linux - [ ] aarch64-linux - [x] x86_64-darwin - [ ] aarch64-darwin - For non-Linux: Is sandboxing enabled in `nix.conf`? (See [Nix manual](https://nixos.org/manual/nix/stable/command-ref/conf-file.html)) - [ ] `sandbox = relaxed` - [ ] `sandbox = true` - [x] Tested, as applicable: - ~[NixOS test(s)](https://nixos.org/manual/nixos/unstable/index.html#sec-nixos-tests) (look inside [nixos/tests]~(https://github.com/NixOS/nixpkgs/blob/master/nixos/tests)) - and/or [package tests](https://github.com/NixOS/nixpkgs/blob/master/pkgs/README.md#package-tests) - ~or, for functions and "core" functionality, tests in [lib/tests](https://github.com/NixOS/nixpkgs/blob/master/lib/tests) or [pkgs/test](https://github.com/NixOS/nixpkgs/blob/master/pkgs/test)~ - ~made sure NixOS tests are [linked](https://github.com/NixOS/nixpkgs/blob/master/pkgs/README.md#linking-nixos-module-tests-to-a-package) to the relevant packages~ - [x] 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](https://github.com/Mic92/nixpkgs-review#usage) - [x] Tested basic functionality of all binary files (usually in `./result/bin/`) - [25.05 Release Notes](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/release-notes/rl-2505.section.md) (or backporting [24.11](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/release-notes/rl-2411.section.md) and [25.05](https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/release-notes/rl-2505.section.md) 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~ - [x] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md).  --- Add a :+1: [reaction] to [pull requests you find important]. [reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/ [pull requests you find important]: https://github.com/NixOS/nixpkgs/pulls?q=is%3Aopen+sort%3Areactions-%2B1-desc

I have never worked with nixpkgs before though so I can’t guarantee it.

reckenrode · April 22, 2025, 10:41am

I’ve started work on cleaning up Swift, so I can update it to Swift 6.1. I am targeting it for 25.11, though I expect it to land sooner rather than later.

reckenrode · May 2, 2025, 3:47am

Thanks for that PR! It helped me find an issue with my changes. When Swift imports a module, it sometimes needs help with headers because it bypasses the Clang wrapper.

Anyway, this is ab example of mas after the update. fetchSwiftPMDdeps is new. It’s similar to fetchCargoVendor. The hook functionality of swiftpm has been split into a separate hook.

gist.github.com

https://gist.github.com/reckenrode/41d94887955b2553514489f728c5532e

package.nix

{
  lib,
  fetchFromGitHub,
  fetchSwiftPMDeps,
  installShellFiles,
  mas,
  replaceVars,
  stdenv,
  swift,
  swiftpmHook,

This file has been truncated. show original

My current status is I have Swift 5.10.1 building, which is needed to bootstrap Swift 6.1. I’m currently doing some testing and working on updating the rest of the packages in swiftPackages.

reckenrode · May 9, 2025, 1:52am

Status update: I have swiftPackages_5 building with all the tools. Swift provides swift-driver. Nothing is wrapped. I have run into a few complications with Swift 6.1.

Swift 6.1 has started using C++ in bridging headers, which goes through its ClangImporter library instead of using the wrapped clang binary.
Swift 6.1 requires compiler-rt features that only became available upstream in LLVM 20. While Swift builds its own LLVM, it uses the default compiler-rt.

I spent the last few days working on a patch to Swift to make it read libcxx-cxxflags from the clang wrapper. It works and can build Swift 5.10.1 with C++ interop. I expect Swift 6.1 should also work with the patch, but I need to update the default version of LLVM to LLVM 20 (which was planned for 25.11 anyway).

zmitchell · August 26, 2025, 6:04pm

Is there a possibility of getting swift-sdk in there as well? It looks like that’s necessary for playing around with the new Containerization package that’s part of macOS 26.

reckenrode · August 27, 2025, 2:33am

The macOS 26 SDK will be added to nixpkgs once macOS 26 is released, and the SDK is publicly available.

reckenrode · August 27, 2025, 2:36am

My current status is I got blocked building on Linux, had a move in July, and have been out of the country without access to a computer for the last two weeks. After I get back, I want to focus on a number of Darwin things that need to land for 25.11, then I can resume working on Swift 6.

The version of Swift will be whatever the public release is, which is currently 6.1.1 but could be 6.2.

zmitchell · August 27, 2025, 5:26am

Just to be clear, I’m talking about this, which I don’t think is the same thing as the typical macOS SDKs: Getting Started with the Static Linux SDK | Swift.org

(Not an expert though, just wanted to poke around at it)

reckenrode · August 28, 2025, 7:28am

Sorry, I misunderstood. I’d forgotten that Apple actually released the source to Containerization.

To answer your question: in the short term, no. My goal for the update is to improve the maintenance situation and start laying the foundation for better Swift support. After that, it should be possible to build on that with better SDK support.

I think there is an opportunity to use Nix to declaratively manage Swift environments and handle cross-compilation, but we can’t even build applications that require Swift 6 right now. That needs fixed first.

reckenrode · September 17, 2025, 2:47am

Swift 6.2 is out, which restores the C++ bootstrap path. That should simplify the update, but it is likely to slip past 25.11 due to my limited availability over the last few months. My focus will still be getting the necessary Darwin updates over the finish line before the freeze.