Re: [PATCH libgpiod 09/10] bindings: rust: update rust version

["Erik Schilling" <erik@riscstar.com>]

On Wed Aug 13, 2025 at 9:12 AM CEST, Bartosz Golaszewski wrote:
> On Wed, Aug 13, 2025 at 8:57 AM Erik Schilling <erik@riscstar.com> wrote:
>>
>> On Tue Aug 12, 2025 at 2:10 PM CEST, Bartosz Golaszewski wrote:
>> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>> >
>> > With all previous fixes to rust bindings, we can now update the rust
>> > version and required edition to 2024.
>> >
>> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>> > ---
>> >  bindings/rust/libgpiod-sys/Cargo.toml | 4 ++--
>> >  bindings/rust/libgpiod/Cargo.toml     | 4 ++--
>> >  2 files changed, 4 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/bindings/rust/libgpiod-sys/Cargo.toml b/bindings/rust/libgpiod-sys/Cargo.toml
>> > index 7fb5c174ec8186b6ef8cd64e1e6f25a13bd0dcd3..ab86ff8ecf871bfc3f931f8ea08490c4eb40eee6 100644
>> > --- a/bindings/rust/libgpiod-sys/Cargo.toml
>> > +++ b/bindings/rust/libgpiod-sys/Cargo.toml
>> > @@ -9,10 +9,10 @@ authors = ["Viresh Kumar <viresh.kumar@linaro.org>"]
>> >  description = "libgpiod public header bindings"
>> >  repository = "https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git"
>> >  categories = ["external-ffi-bindings", "os::linux-apis"]
>> > -rust-version = "1.60"
>> > +rust-version = "1.86"
>> >  keywords = ["libgpiod", "gpio"]
>> >  license = "Apache-2.0 OR BSD-3-Clause"
>> > -edition = "2021"
>> > +edition = "2024"
>> >
>> >  exclude = [
>> >      "Makefile.am",
>>
>> Is there a particular reason to to pick this specific rust-version? This
>> essentially sets the floor of the MSRV (Minimum Supported Rust Version)
>> of this lib.
>>
>> That means that it won't build with any older Rust version, which may
>> impact users of the lib that are still lagging slightly behind?
>>
>
> I'm probably talking nonsense right from the top of Mount Stupid[1]
> here but is this bad in rust? With the ease of updating everything via
> cargo, I figured requiring the most recent version makes sense? I'll
> defer to you as you have way more knowledge on this subject, so tell
> me if I should drop this.

It certainly is a lot less of a problem with Rust. But projects may
still be lagging behind a few versions if they have some dependency
problems. Rust through rustup is also not the only option of consuming
Rust. One could also work with a Rust toolchain from Yocto and be stuck
with an older Yocto version.

>> I would only bump this if our libs start to require it (or we use new
>> features ourselves). So I think we should spell out which libs/features
>> mandate this bump in the commit message and only update as high as we
>> need to.
>>
>
> Nobody requires it AFAICT.

If we still build and `cargo test` fine with 1.60, then I would keep
that version :). Once our dependencies start demanding newer versions
we can update (to the lowest version that the union of our dependencies
still supports).

Or phrased differently: No need to make our work harder by sticking to
old dependencies. But no need to prematurely raise the version floor
too.

- Erik