Re: [PATCH v4] scripts: checkpatch: warn on Rust panicking methods

[Dirk Behme <dirk.behme@de.bosch.com>]

Hi Jason,

On 02/02/2026 14:56, Jason Hall wrote:
> Add regex check in checkpatch.pl for common Rust panicking methods
> like unwrap() and expect().
> 
> Allow an exception if the line contains a '// PANIC:' comment.
> 
> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> Link: https://github.com/Rust-for-linux/linux/issues/1191
> Signed-off-by: Jason Hall <jason.kei.hall@gmail.com>
> ---
> Hi Dirk,
> 
> Now using imperative mood.  I decided to keep that logic stateless
> unless its agreed that we need to add state.  Adding checks for #[test]
> and other test identifiers will make this much more complicated.  There
> is already a check for // PANIC: that works fine.


Yes. I'm just slightly unclear what we do with existing code where using 
`unwrap()` is fine/accepted/required? And with patches like

https://lore.kernel.org/rust-for-linux/20260131154016.270385-3-shivamklr@cock.li/

I would guess with this change we would get warnings on that?

So the idea is that we would need some add-on patches on top of this to 
annotate existing code / patches with `// PANIC: ...` to stay warning clean?

Thanks,

Dirk

Btw, what's with Gary's comment to drop `expect()`?


> v4:
>   - Use imperative mood in commit description.
>   - Fix patch formatting and placement of '---' separator.
> v3:
>   - Use non-capturing groups (?:) to optimize regex.
> v2:
>   - Switch from \b to (\.|::) to avoid false positives in strings.
>   - Add : to PANIC comment check.
> 
>   scripts/checkpatch.pl | 11 +++++++++++
>   1 file changed, 11 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index c0250244cf7a..37bdf602e7e7 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -3834,6 +3834,17 @@ sub process {
>   # check we are in a valid source file if not then ignore this hunk
>   		next if ($realfile !~ /\.(h|c|rs|s|S|sh|dtsi|dts)$/);
>   
> +# check for Rust unwrap/expect
> +		if ($realfile =~ /\.rs$/ && $line =~ /^\+/) {
> +			if ($line =~ /(?:\.|::)(?:unwrap|expect)\s*\(/ &&
> +				$rawline !~ /\/\/\s*PANIC:/ &&
> +				$line !~ /^\+\s*\/\// &&
> +				$line !~ /^\+\s*assert/) {
> +				WARN("RUST_UNWRAP",
> +					"Avoid unwrap() or expect() in Rust code; use proper error handling (Result) or justify with a '// PANIC: ...' comment.\n" . $herecurr);
> +			}
> +		}
> +
>   # check for using SPDX-License-Identifier on the wrong line number
>   		if ($realline != $checklicenseline &&
>   		    $rawline =~ /\bSPDX-License-Identifier:/ &&