Re: [PATCH] checkpatch: warn on unhandled placeholders in cover letters

[Onur Özkan]

On Wed, 17 Sep 2025 14:49:09 +0300
Onur Özkan <work@xxxxxxxxxxxxx> wrote:

> Adds a new check to detect unhandled placeholders in cover letters.
> This prevents sending patch series with incomplete cover letters
> containing auto generated subject or blurb lines such as:
> 
>     *** SUBJECT HERE ***
>     *** BLURB HERE ***
> 
> These placeholders can be seen on mailing lists (e.g., searching
> for "BLURB HERE" on lore.kernel.org). With this patch, checkpatch
> will emit a warning when such text is found.
> 
> Example output on an invalid cover letter:
> 
>     WARNING: Incomplete cover letter: placeholder text detected
>     #4: FILE: ./0000-cover-letter.patch:4:
>     +Subject: [PATCH 0/4] *** SUBJECT HERE ***
> 
>     WARNING: Incomplete cover letter: placeholder text detected
>     #9: FILE: ./0000-cover-letter.patch:9:
>     +*** BLURB HERE ***
> 
>     total: 0 errors, 2 warnings, 24 lines checked
> 
>     NOTE: For some of the reported defects, checkpatch may be able to
> 	  mechanically convert to the typical style using --fix or
> --fix-inplace.
> 
>     ./0000-cover-letter.patch has style problems, please review.
> 
>     NOTE: If any of the errors are false positives, please report
> 	  them to the maintainer, see CHECKPATCH in MAINTAINERS.
> 
> Signed-off-by: Onur Özkan <work@xxxxxxxxxxxxx>
> ---
>  scripts/checkpatch.pl | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index e722dd6fa8ef..9d5ded376112 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -3339,6 +3339,15 @@ sub process {
>  				$fixed[$fixlinenr] =~ s/^/ /;
>  			}
>  		}
> +# Check for unhandled placeholder text in cover letters
> +		if ($filename =~ /cover-letter\.patch$/) {
> +			if ($rawline =~ /^\+Subject:.*\*\*\* SUBJECT
> HERE \*\*\*/ ||
> +				$rawline =~ /^\+\*\*\* BLURB HERE
> \*\*\*/) {
> +				my $placeholder = $1 || $2;
> +				WARN("COVER_LETTER_PLACEHOLDER",
> +					 "Incomplete cover letter:
> placeholder text detected\n" . $herecurr);
> +			}
> +		}
>  
>  # Check for git id commit length and improperly formed commit
> descriptions # A correctly formed commit description is:

I wasn't aware of the checkpatch documentation in
"Documentation/dev-tools/checkpatch.rst" file. I guess
COVER_LETTER_PLACEHOLDER needs to be documented there?

Regards,
Onur