Re: [PATCH v5] scripts: checkpatch: move Rust-specific lints to separate file

[Dirk Behme]

On 05.02.2026 21:55, Miguel Ojeda wrote:
> On Thu, Feb 5, 2026 at 2:42 AM Jason Hall <jason.kei.hall@xxxxxxxxx> wrote:
> > Move Rust linting logic into scripts/rust_checkpatch.pl to prevent
> > further growth of the main checkpatch.pl script.
> >
> > Warn against the use of .unwrap() and .expect() unless accompanied by
> > a '// PANIC:' comment. This enforces safety standards in the Rust-
> > for-Linux project until upstream Clippy lints are integrated.
> >
> > Suggested-by: Joe Perches <joe@xxxxxxxxxxx>
> > Suggested-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
> > Link: https://github.com/Rust-for-linux/linux/issues/1191
> > Signed-off-by: Jason Hall <jason.kei.hall@xxxxxxxxx>
>
> Ideally, this would be two patches -- one performing the move and the
> other adding the new lint.
>
> Either way, the file should be added to `MAINTAINERS` -- not sure if
> Joe would want to maintain it or perhaps have a new sub-entry or
> perhaps a co-maintainer etc.
>
> > +                    "Avoid unwrap() or expect() in Rust code; use proper error handling (Result) or justify with a '// PANIC: ...' comment.\n" . $herecurr);
>
> By "proper error handling", I guess you mean bubbling the error up
> with `?` or similar, right?
>
> There are also other options, like using `unsafe` sometimes etc.
>
> I think perhaps the best is to keep the message a bit less strict
> (since there are cases where it is OK) and put the details in a link
> to, say, https://rust.docs.kernel.org/kernel/error/type.Result.html#error-codes-in-c-and-rust
> (Cc'ing Dirk who was involved in that).
>
> I am thinking of something like:
>
>      `unwrap()` and `expect()` should generally be avoided in Rust


Gary had some concerns about `expect()` in

https://lore.kernel.org/rust-for-linux/DG3VYAW3TXEO.1YG8N99YWCDR6@xxxxxxxxxxx/


> kernel code modulo some exceptions (e.g. within asserts in doctests

... and `tests`)

? See

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/rust/kernel/alloc/kvec.rs?h=v6.19-rc8#n1355

).
> If the use is intended, then please justify it with a `// PANIC:`
> comment. Please see ...


I'm totally fine with this. In consequence do we agree that this will 
result in some follow up patches annotating the existing "allowed" 
exceptional / intended cases (e.g. in doctests and tests) with `// 
PANIC:` comments?

Best regards

Dirk



> But I will let others comment...
>
> (Also, please Cc all the maintainers/reviews of Rust and checkpatch --
> doing so here).
>
> Thanks!
>
> Cheers,
> Miguel