Re: [PATCH v2 0/5] rust: generate bindings via cbindgen

[Patrick Steinhardt <ps@pks.im>]

On Tue, Oct 28, 2025 at 01:37:00PM -0600, Ezekiel Newren wrote:
> On Fri, Oct 24, 2025 at 3:51 AM Patrick Steinhardt <ps@pks.im> wrote:
> >
> > Hi,
> >
> > this small patch series introduces support for cbindgen(1). This tool is
> > used to generate C headers from `extern "C"` blocks so that Rust code
> > can easily be called from C code.
> >
> > For now, the only use case is to verify that our varint reimplementation
> > matches the C implementation. But later on this can and will be used to
> > call Rust-specific features from C, as well.
> >
> > The topic is built on top of c54a18ef67 (The twenty-second batch,
> > 2025-10-22) with ps/ci-rust at e509b5b8be (rust: support for Windows,
> > 2025-10-15) merged into it.
> >
> > Changes in v2:
> >   - Take some of the pieces from Ezekiel's "cbindgen.toml" file. I have
> >     not yet taken `usize_is_size_t`, as that option requires cbindgen
> >     v0.16.0, which is not available on Ubuntu 20.04.
> >   - Backfill missing jobs for GitLab CI.
> >   - Fix CI failures on Alma Linux 8 because cbindgen isn't available
> >     there.
> >   - Link to v1: https://lore.kernel.org/r/20251023-b4-pks-rust-cbindgen-v1-0-c19b61b03127@pks.im
> 
> I really think that this patch series should include migrating to a
> Cargo Workspace. That'll mean moving /Cargo.toml and /src into
> gitcore/ and creating a new top-level /Cargo.toml with the following
> content:
> [workspace]
> members = [
>     "gitcore",
> ]
> resolver = "2"
> 
> Along with the other cascading refactor changes needed to make this
> work. Let's do this now while it's still easy.

I simply think that cbindgen and workspaces are quite unrelated to one
another for now. So an alternate suggestion: once this patch series here
lands we could introduce workspaces in the subsequent patch series. I
think that's still early enough, and this patch series here shouldn't
cause significant additional churn.

In any case, I'd prefer if you wrote that patch series to introduce
workspaces. I don't feel like I have enough experience with them to be
able to argue properly why we want to have them.

Does that work for you?

Thanks!

Patrick