Re: [PATCH] checkpatch: exclude forward declarations of const structs

[Joe Perches]

On Tue, 2026-03-31 at 13:26 -0400, Taylor Nelms wrote:
> ```
> Limit checkpatch warnings for normally-const structs by excluding
> patterns consistent with forward declarations.
> 
> For example, the forward declaration `struct regmap_access_table;` in a
> header file currently generates a warning recommending that it is
> generally declared as const; however, this would apply a useless type
> qualifier in the empty declaration `const struct regmap_access_table;`,
> and subsequently generate compiler warnings.
> 
> Signed-off-by: Taylor Nelms <[tknelms@xxxxxxxxxx](mailto:tknelms@xxxxxxxxxx)>

Seems sensible, thanks but:

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -7502,10 +7502,10 @@ sub process {
>  		}
>  
>  # check for various structs that are normally const (ops, kgdb, device_tree)
> -# and avoid what seem like struct definitions 'struct foo {'
> +# and avoid what seem like struct definitions 'struct foo {' or forward declarations 'struct foo;'
>  		if (defined($const_structs) &&
>  		    $line !~ /\bconst\b/ &&
> -		    $line =~ /\bstruct\s+($const_structs)\b(?!\s*\{)/) {
> +		    $line =~ /\bstruct\s+($const_structs)\b(?!\s*(\{|;))/) {

Prefer using (?:\{|;) to avoid capture groups or maybe [\{;]