Subject: Re: [PATCH 01/33] rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)

From: Alice Ryhl <[email-masked]>
Date: Wed, 1 Apr 2026 12:24:55 +0000

On Wed, Apr 01, 2026 at 01:45:08PM +0200, Miguel Ojeda wrote:
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
> 
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).

Debian really *should* pick up 1.85.1. It contains bugfixes serious
enough that the Rust team decided it was reasonble to release a point
release.

> Debian Trixie's release happened on 2025-08-09 [4], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
> 
> Thus bump the minimum to the new version.
> 
> Then, in later commits, clean up most of the workarounds and other bits
> that this upgrade of the minimum allows us.
> 
> pin-init was left as-is since the patches come from upstream. And the
> vendored crates are unmodified, since we do not want to change those.
> 
> Note that the minimum LLVM major version for Rust 1.85.0 is LLVM 18 (the
> Rust upstream binaries use LLVM 19.1.7), thus e.g. `RUSTC_LLVM_VERSION`
> tests can also be updated, but there are no suitable ones to simplify.
> 
> Ubuntu 25.10 also has a recent enough Rust toolchain [5], and they also
> provide versioned packages with a Rust 1.85.1 toolchain even back to
> Ubuntu 22.04 LTS [6].
> 
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://www.debian.org/releases/trixie/ [4]
> Link: https://packages.ubuntu.com/search?suite=all&searchon=names&keywords=rustc [5]
> Link: https://launchpad.net/ubuntu/+source/rustc-1.85 [6]
> Signed-off-by: Miguel Ojeda <[email-masked]>

Acked-by: Alice Ryhl <[email-masked]>