Demote `x86_64-apple-darwin` from Tier 1 to Tier 2 with host tools #3841

shepmaster · 2025-07-23T13:31:31Z

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text/3841-demote-x86_64-apple-darwin.md

Noratrieb · 2025-07-23T16:21:50Z

Starting FCP already, we don't have many options here.
@rfcbot fcp merge

rfcbot · 2025-07-23T16:21:52Z

RalfJung · 2025-07-25T06:57:44Z

text/3841-demote-x86_64-apple-darwin.md

+
+The first release after this RFC is merged will be the last one with Tier 1 support for the `x86_64-apple-darwin` target.
+The release after that will demote the target to Tier 2 with host tools,
+which means it will not be tested by CI.


FWIW, we do run some tests for non-tier-1-targets, e.g. some i586 targets. We could probably do the same for x86_64-apple-darwin? IOW, the consequence of this RFC is that we stop promising that we run all the tests, and we'll drop what is impractical, but we don't have to drop everything immediately. We could, for instance, keep running the library tests under rosetta, which shouldn't take too long.

Yes, it may be feasible for rust-lang/rust to run a subset of tests still for x86_64-apple-darwin, this RFCs just drops that promise. This wording is somewhat accurate in that it's definitely a possibility for us to not run any tests (as per Tier 2 support level), even if that seems unlikely.

I think that would be good to communicate clearly, also in the blog post: we don't actually plan to drop all tests immediately, we'll continue testing some things under Rosetta where feasible, etc.

Or is our plan really to drop all tests entirely when we stop using the free macos-13 runners?

Or is our plan really to drop all tests entirely when we stop using the free macos-13 runners?

I think the intention is to keep that open as a possibility in case it becomes necessary.

Right, that's what I figured. I think this needs to be quite explicit, or people will conclude that we are dropping all tests immediately.

I don't think we can necessarily guarantee that

The RFC currently basically suggests that we guarantee that we don't run any tests.
That is not the same as not guaranteeing that we run all the tests.

The RFC currently basically suggests that we guarantee that we don't run any tests. That is not the same as not guaranteeing that we run all the tests.

So something like

This means that it is no longer guaranteed that the x86_64-apple-darwin target will be tested in CI

Which includes the possibility that no tests for x86_64-apple-darwin is run at all?

Yes. It's definitely a possibility, but it's a matter of continuous evaluation.

Is this better?

diff --git a/text/3841-demote-x86_64-apple-darwin.md b/text/3841-demote-x86_64-apple-darwin.md index e1e72361..942446ae 100644 --- a/text/3841-demote-x86_64-apple-darwin.md +++ b/text/3841-demote-x86_64-apple-darwin.md @@ -71,7 +71,7 @@ we can see that `x86_64-apple-darwin` has substantially fewer downloads than `aa The first release after this RFC is merged will be the last one with Tier 1 support for the `x86_64-apple-darwin` target. The release after that will demote the target to Tier 2 with host tools, -which means it will not be tested by CI. +which means we no longer guarantee that it will be tested by CI. Once this RFC is merged, a blog post will be published on the main Rust Blog announcing the change to alert users of the demotion.

Yes, I would prefer that.

jieyouxu · 2025-07-28T15:26:24Z

Friendly nudge for the remaining FCP reviewers (would not have done so if it's not as time-sensitive), as on 2025-09-01 GitHub will discontinue providing free macOS x86_64 runners for public repositories, which won't leave us a lot of time for doing the demotion accounting for FCP time.

cc @cjgillot @nagisa @spastorino @wesleywiser

RalfJung · 2025-07-28T15:29:45Z

@rfcbot concern dont-commit-to-dropping-all-test-coverage

(Not sure if I can raise concerns here? I'm in t-compiler but not a "maintainer".)

I think we shouldn't prescribe in the RFC that we stop all tests. I think we should just say we stop guaranteeing that all tests are run. That's a big difference. The stats show there's still a lot of x86_64-apple users out there, so it's too early to drop all test coverage entirely.

text/3841-demote-x86_64-apple-darwin.md

jieyouxu · 2025-07-28T15:54:48Z

@rfcbot concern test-coverage-wording

I think we shouldn't prescribe in the RFC that we stop all tests. I think we should just say we stop guaranteeing that all tests are run. That's a big difference. The stats show there's still a lot of x86_64-apple users out there, so it's too early to drop all test coverage entirely.

-- #3841 (comment)

jieyouxu · 2025-07-29T03:37:26Z

Resolving test-coverage-wording concern given positive feedback and wording adjustment.

@rfcbot resolve test-coverage-wording

rfcbot · 2025-07-29T10:48:05Z

🔔 This is now entering its final comment period, as per the review above. 🔔

rfcbot · 2025-08-08T10:51:30Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

stacksjb · 2025-08-08T21:18:55Z

This seems extremely early, given that Apple is continuing to support MacOS Intel until 2028

Is the primary issue an inability to provide ongoing support due to GitHub Runner deprecation (which is still largely up in the air, as newer OS images can likely run on AMD64 - see actions/runner-images#12520 )

pietroalbini · 2025-08-09T07:58:14Z

Is the primary issue an inability to provide ongoing support due to GitHub Runner deprecation (which is still largely up in the air, as newer OS images can likely run on AMD64 - see actions/runner-images#12520 )

Newer OS images are available for x86_64, but only on the paid large runners. We can only use the free macOS runners. The part of the announcement relevant to us is that macos-13 is the only x86_64 image available on free runners.

This MR contains the following updates: | Package | Update | Change | |---|---|---| | [rust](https://github.com/rust-lang/rust) | minor | `1.88.0` -> `1.89.0` | MR created with the help of [el-capitano/tools/renovate-bot](https://gitlab.com/el-capitano/tools/renovate-bot). **Proposed changes to behavior should be submitted there as MRs.** --- ### Release Notes <details> <summary>rust-lang/rust (rust)</summary> ### [`v1.89.0`](https://github.com/rust-lang/rust/blob/HEAD/RELEASES.md#Version-1890-2025-08-07) [Compare Source](rust-lang/rust@1.88.0...1.89.0) \========================== <a id="1.89.0-Language"></a> ## Language - [Stabilize explicitly inferred const arguments (`feature(generic_arg_infer)`)](rust-lang/rust#141610) - [Add a warn-by-default `mismatched_lifetime_syntaxes` lint.](rust-lang/rust#138677) This lint detects when the same lifetime is referred to by different syntax categories between function arguments and return values, which can be confusing to read, especially in unsafe code. 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[platform-support-doc]: https://doc.rust-lang.org/rustc/platform-support.html <a id="1.89.0-Libraries"></a> ## Libraries - [Specify the base path for `file!`](rust-lang/rust#134442) - [Allow storing `format_args!()` in a variable](rust-lang/rust#140748) - [Add `#[must_use]` to `[T; N]::map`](rust-lang/rust#140957) - [Implement `DerefMut` for `Lazy{Cell,Lock}`](rust-lang/rust#129334) - [Implement `Default` for `array::IntoIter`](rust-lang/rust#141574) - [Implement `Clone` for `slice::ChunkBy`](rust-lang/rust#138016) - [Implement `io::Seek` for `io::Take`](rust-lang/rust#138023) <a id="1.89.0-Stabilized-APIs"></a> ## Stabilized APIs - [`NonZero<char>`](https://doc.rust-lang.org/stable/std/num/struct.NonZero.html) - Many intrinsics for x86, not enumerated here - [AVX512 intrinsics](rust-lang/rust#111137) - [`SHA512`, `SM3` and `SM4` intrinsics](rust-lang/rust#126624) - [`File::lock`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock) - [`File::lock_shared`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.lock_shared) - [`File::try_lock`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock) - [`File::try_lock_shared`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.try_lock_shared) - [`File::unlock`](https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.unlock) - [`NonNull::from_ref`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_ref) - [`NonNull::from_mut`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.from_mut) - [`NonNull::without_provenance`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.without_provenance) - [`NonNull::with_exposed_provenance`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.with_exposed_provenance) - [`NonNull::expose_provenance`](https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.expose_provenance) - [`OsString::leak`](https://doc.rust-lang.org/stable/std/ffi/struct.OsString.html#method.leak) - [`PathBuf::leak`](https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#method.leak) - [`Result::flatten`](https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.flatten) - [`std::os::linux::net::TcpStreamExt::quickack`](https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.quickack) - [`std::os::linux::net::TcpStreamExt::set_quickack`](https://doc.rust-lang.org/stable/std/os/linux/net/trait.TcpStreamExt.html#tymethod.set_quickack) These previously stable APIs are now stable in const contexts: - [`<[T; N]>::as_mut_slice`](https://doc.rust-lang.org/stable/std/primitive.array.html#method.as_mut_slice) - [`<[u8]>::eq_ignore_ascii_case`](https://doc.rust-lang.org/stable/std/primitive.slice.html#impl-%5Bu8%5D/method.eq_ignore_ascii_case) - [`str::eq_ignore_ascii_case`](https://doc.rust-lang.org/stable/std/primitive.str.html#impl-str/method.eq_ignore_ascii_case) <a id="1.89.0-Cargo"></a> ## Cargo - [`cargo fix` and `cargo clippy --fix` now default to the same Cargo target selection as other build commands.](rust-lang/cargo#15192) Previously it would apply to all targets (like binaries, examples, tests, etc.). 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See the [FCP report](rust-lang/rust#137944 (comment)) for a code example. - The warn-by-default `elided_named_lifetimes` lint is [superseded by the warn-by-default `mismatched_lifetime_syntaxes` lint.](rust-lang/rust#138677) - [Error on recursive opaque types earlier in the type checker](rust-lang/rust#139419) - [Type inference side effects from requiring element types of array repeat expressions are `Copy` are now only available at the end of type checking](rust-lang/rust#139635) - [The deprecated accidentally-stable `std::intrinsics::{copy,copy_nonoverlapping,write_bytes}` are now proper intrinsics](rust-lang/rust#139916). 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Due to decreasing support from github and rust: https://blog.rust-lang.org/2025/08/07/Rust-1.89.0/#demoting-x86-64-apple-darwin-to-tier-2-with-host-tools rust-lang/rfcs#3841 https://github.blog/changelog/2025-07-11-upcoming-changes-to-macos-hosted-runners-macos-latest-migration-and-xcode-support-policy-updates/#macos-13-is-closing-down

shepmaster added T-compiler Relevant to the compiler team, which will review and decide on the RFC. T-release Relevant to the release team, which will review and decide on the RFC. labels Jul 23, 2025

shepmaster force-pushed the demote-x86_64-apple-darwin branch 2 times, most recently from 84fcc97 to 242cfad Compare July 23, 2025 13:33

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rfcbot added proposed-final-comment-period Currently awaiting signoff of all team members in order to enter the final comment period. disposition-merge This RFC is in PFCP or FCP with a disposition to merge it. labels Jul 23, 2025

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ci(macos): run x64 workflows with Rosetta 2 rust-lang/rustup#4428

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rfcbot added final-comment-period Will be merged/postponed/closed in ~10 calendar days unless new substational objections are raised. and removed proposed-final-comment-period Currently awaiting signoff of all team members in order to enter the final comment period. labels Jul 29, 2025

rfcbot added finished-final-comment-period The final comment period is finished for this RFC. to-announce and removed final-comment-period Will be merged/postponed/closed in ~10 calendar days unless new substational objections are raised. labels Aug 8, 2025

shepmaster force-pushed the demote-x86_64-apple-darwin branch from 5a1eaf8 to 414c087 Compare August 11, 2025 14:51

Demote x86_64-apple-darwin from Tier 1 to Tier 2 with host tools

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shepmaster force-pushed the demote-x86_64-apple-darwin branch from 414c087 to 69b3c2f Compare August 11, 2025 14:53

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shepmaster deleted the demote-x86_64-apple-darwin branch August 11, 2025 14:54

madsmtm mentioned this pull request Aug 12, 2025

Demote x86_64-apple-darwin to Tier 2 with host tools rust-lang/rust#145252

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Demote x86_64-apple-darwin from Tier 1 to Tier 2 with host tools #3841

Demote x86_64-apple-darwin from Tier 1 to Tier 2 with host tools #3841

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Demote `x86_64-apple-darwin` from Tier 1 to Tier 2 with host tools #3841

Demote `x86_64-apple-darwin` from Tier 1 to Tier 2 with host tools #3841

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