[Linux-kernel-mentees] [PATCH] checkpatch: add fix and improve warning msg for Non-standard signature

Lukas Bulwahn lukas.bulwahn at gmail.com
Tue Nov 24 11:48:07 UTC 2020


On Tue, Nov 24, 2020 at 12:17 PM Aditya Srivastava <yashsri421 at gmail.com> wrote:
>
> Currently checkpatch warns for BAD_SIGN_OFF on non-standard signature
> styles.
>
> A large number of these warnings occur because of typo mistakes in
> signoffs.
> An evaluation over v4.13..v5.8 revealed that out of 539 warnings due to
> Non-standard signatures, 85 are due to typo mistakes.
>
> Eg. running checkpatch on commit da785a87787c ("ARM: bcm2835: Fix
> integer overflow in rpi_firmware_print_firmware_revision()") reports
> this warning:
>
> WARNING:Non-standard signature: Revieved-by:
> Revieved-by: Petr Mladek <pmladek at suse.com>
>
> Here the signoff 'Reviewed-by' is misspelt.
>

Again, it is better to provide a summary of the overall evaluation
instead of a single example,

> Provide a fix by calculating levenshtein distance for the signoff over

it is a signature tag, not the signoff.

> all the standard signatures and suggest a fix if the distance for any
> signature is less than or equal to 2.
>
> Signed-off-by: Aditya Srivastava <yashsri421 at gmail.com>
> ---
> applied on my last patch and next-20201120
>

Joe, might ack this one and reject the other; so you might need to rebase later.

For the discussion with Joe now that is fine, though.

Other than that, it looks good.

>  scripts/checkpatch.pl | 73 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index b018deecec1a..2198360eebbd 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -506,6 +506,77 @@ our $signature_tags = qr{(?xi:
>         Cc:
>  )};
>
> +sub get_min {
> +       my (@arr) = @_;
> +       my $len = scalar @arr;
> +       if((scalar @arr) < 1) {
> +               # if underflow, return
> +               return;
> +       }
> +       my $min = $arr[0];
> +       for my $i (0 .. ($len-1)) {
> +               if ($arr[$i] < $min) {
> +                       $min = $arr[$i];
> +               }
> +       }
> +       return $min;
> +}
> +
> +sub get_edit_distance {
> +       my ($str1, $str2) = @_;
> +       my $len1 = length($str1);
> +       my $len2 = length($str2);
> +       # two dimensional array storing minimum edit distance
> +       my @distance;
> +       for my $i (0 .. $len1) {
> +               for my $j (0 .. $len2) {
> +                       if ($i == 0) {
> +                               $distance[$i][$j] = $j;
> +                       }
> +                       elsif ($j == 0) {
> +                               $distance[$i][$j] = $i;
> +                       }
> +                       elsif (substr($str1, $i-1, 1) eq substr($str2, $j-1, 1)) {
> +                               $distance[$i][$j] = $distance[$i - 1][$j - 1];
> +                       }
> +                       else {
> +                               my $dist1 = $distance[$i][$j - 1]; #insert distance
> +                               my $dist2 = $distance[$i - 1][$j]; # remove
> +                               my $dist3 = $distance[$i - 1][$j - 1]; #replace
> +                               $distance[$i][$j] = 1 + get_min($dist1, $dist2, $dist3);
> +                       }
> +               }
> +       }
> +       return $distance[$len1][$len2];
> +}
> +
> +sub get_standard_signature {
> +       my ($sign_off) = @_;
> +       $sign_off = lc($sign_off);
> +       $sign_off =~ s/\-//g; # to match with formed hash
> +       my @standard_signature_tags = (
> +               'signed-off-by:', 'co-developed-by:', 'acked-by:', 'tested-by:',
> +               'reviewed-by:', 'reported-by:', 'suggested-by:', 'to:', 'cc:'
> +       );
> +       # setting default values
> +       my $standard_signature = 'signed-off-by';
> +       my $min_edit_distance = 20;
> +       my $edit_distance;
> +       foreach (@standard_signature_tags) {
> +               my $signature = $_;
> +               $_ =~ s/\-//g;
> +               $edit_distance = get_edit_distance($sign_off, $_);
> +               if ($edit_distance < $min_edit_distance) {
> +                       $min_edit_distance = $edit_distance;
> +                       $standard_signature = $signature;
> +               }
> +       }
> +        if($min_edit_distance<=2) {
> +               return ucfirst($standard_signature);
> +        }
> +       return "";
> +}
> +
>  our %standard_signature_fix = (
>         "Requested-by:" => {
>                 suggestion => "Suggested-by:",
> @@ -2848,7 +2919,7 @@ sub process {
>                         my $ucfirst_sign_off = ucfirst(lc($sign_off));
>
>                         if ($sign_off !~ /$signature_tags/) {
> -                               my $suggested_signature = "";
> +                               my $suggested_signature = get_standard_signature($sign_off);
>                                 my $rationale = "";
>                                 if (exists($standard_signature_fix{$sign_off})) {
>                                         $suggested_signature = $standard_signature_fix{$sign_off}{'suggestion'};
> --
> 2.17.1
>


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