Re: [PATCH RFC v2 1/7] meson: add infrastructure to build internal Rust library

> On Fri, Sep 5, 2025 at 4:51 AM Patrick Steinhardt <ps@pks.im> wrote:
> >
> > Add the infrastructure into Meson to build an internal Rust library.
> > Building the Rust parts of Git are for now entirely optional, as they
> > are mostly intended as a test balloon for both Git developers, but also
> > for distributors of Git. So for now, they may contain:
> >
> >   - New features that are not mission critical to Git and that users can
> >     easily live without.
> >
> >   - Alternative implementations of small subsystems.
> >
> > If these test balloons are successful, we will eventually make Rust a
> > mandatory dependency for our build process in Git 3.0.
> 
> Okay.
> 
> > The availability of a Rust toolchain will be auto-detected by Meson at
> > setup time. This behaviour can be tweaked via the `-Drust=` feature
> > toggle.
> 
> This goes against what you said above, because it turns it into
> something other than a test balloon.  As I've said elsewhere, I don't
> think this part is helpful; it reduces the amount of notice that
> distributors and platforms have about our intent to make Rust
> mandatory.

> > diff --git a/src/meson.build b/src/meson.build
> > new file mode 100644
> > index 00000000000..eb752651d35
> > --- /dev/null
> > +++ b/src/meson.build
> > @@ -0,0 +1,15 @@
> > +libgit_rs = static_library('git_rs',
> > +  sources: [
> > +    'lib.rs',
> > +  ],
> > +  rust_crate_type: 'staticlib',
> > +)
> > +libgit_libraries += libgit_rs
> > +
> > +# The 'rust' module was only introduced in Meson 1.0. Furthermore, the module
> > +# does not seem to work on macOS as expected right now. As such, we only
> > +# conditionally enable tests.
> > +if meson.version().version_compare('>=1.0.0') and host_machine.system() != 'darwin'
> > +  rustmod = import('rust')
> > +  rustmod.test('rust', libgit_rs)
> > +endif
> 
> Would it make sense to invoke 'cargo test' as one step of 'meson test'
> on mac as an alternative, so that mac users also can run the tests?