Re: [PATCH] rust: kbuild: disambiguate `zerocopy_derive` for `rusttest`

On Sun, Aug 23, 2026 at 9:35 PM Miguel Ojeda <[email protected]> wrote:
>
> The `rustc-dev` components for Rust 1.82.0 through 1.87.0 include a
> precompiled `zerocopy_derive` procedural macro in the sysroot. This
> range includes Rust 1.85.0, our minimum supported version.
>
> This makes `rusttest` fail because the compiler finds both the sysroot
> copy and the copy built in `rust/test`:
>
>     error[E0464]: multiple candidates for `dylib` dependency `zerocopy_derive` found
>       --> rust/kernel/prelude.rs:70:9
>        |
>     70 | pub use zerocopy_derive::{
>        |         ^^^^^^^^^^^^^^^
>        |
>        = note: candidate #1: .../lib/rustlib/x86_64-unknown-linux-gnu/lib/libzerocopy_derive-54d2b38896fa6bc5.so
>        = note: candidate #2: .../rust/test/libzerocopy_derive.so
>
> Commit fe39a233ea52 ("rust: kbuild: disambiguate `zerocopy` for
> `rusttest`") fixed the equivalent ambiguity for `zerocopy`.
>
> Thus point to the dependency explicitly in this case too.
>
> Cc: Antoni Boucher <[email protected]>
> Cc: [email protected]
> Fixes: 506054980429 ("rust: zerocopy-derive: enable support in kbuild")
> Signed-off-by: Miguel Ojeda <[email protected]>

Applied to `rust-fixes`.

Cheers,
Miguel