When is Rust going to have a stable distro experience? [LWN.net]

When is Rust going to have a stable distro experience?

Posted Jun 27, 2025 12:19 UTC (Fri) by laarmen (subscriber, #63948)
In reply to: When is Rust going to have a stable distro experience? by taladar
Parent article: Getting extensions to work with free-threaded Python

> The current Rust compiler is perfectly capable of compiling anything Rust 1.74.0 could compile so there is no reason to have LTS versions of old compiler branches.

This statement is wrong for a couple of reasons. First, there is the odd project that uses unstable features, thus relying on semantics that are by definition subject to change. The rust-for-linux project is (was?) one of those. If you work on the kernel you definitely want to keep older versions of the toolchain around. rustc itself is also one of those, btw. Building an older version of rustc with a newer one doesn't work.

Second, it's actually pretty easy to find an example of code that was fine on 1.74 and doesn't compile today. The 1.80 release famously broke any version of the time crate that was older than 3 months at the time.

I actually think that was fine, although annoying. When you have things like type inference, autoderef, lifetime inference, etc... you're bound to break edge-cases whenever you touch the algorithms, and the resulting QoL changes were probably worth the breakage. However, I do wish people would be more nuanced when mentioning the backwards compatibility story of Rust.

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When is Rust going to have a stable distro experience?

Posted Jun 27, 2025 13:12 UTC (Fri) by daroc (editor, #160859) [Link] (3 responses)

The Rust-for-Linux project does still depend on some unstable features, but reducing the number is a major priority for the Rust project, and one that they have made some decent progress on. Most of the remaining items are build flags, not language features. I would not be surprised if the kernel builds with stable Rust this time next year.

When is Rust going to have a stable distro experience?

Posted Jun 27, 2025 14:49 UTC (Fri) by ojeda (subscriber, #143370) [Link]

Yeah, we rely on essentially 2 language features at the moment, which are being worked on upstream to stabilize them.

Nevertheless, to clarify on top of what Daroc said, we already support stable Rust releases >= 1.78 (i.e. more than a year of releases at the moment).

In other words, from the kernel side we are able to support several versions of the compiler even if some details here and there may happen to change. It is essentially the same as supporting C flags or attributes conditionally, or having a workaround for a compiler bug.

When is Rust going to have a stable distro experience?

Posted Jun 27, 2025 14:57 UTC (Fri) by archaic (subscriber, #111970) [Link] (1 responses)

Can we use this as one of Jon's famous year-end predictions? :)

When is Rust going to have a stable distro experience?

Posted Jun 27, 2025 15:04 UTC (Fri) by daroc (editor, #160859) [Link]

He asks for suggestions from the rest of us when putting those articles together, so I'll certainly throw this one into the ring. Of course, by December we might have a clearer idea of exactly where things will stand.