Re: [PATCH] scripts/checkpatch: emit a warning if an imported file is touched

[Stefano Garzarella]

On Wed, Jul 17, 2024 at 11:58:46AM GMT, Cornelia Huck wrote:
> On Wed, Jul 17 2024, Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> > If a file imported from Linux is touched, emit a warning and suggest
> > using scripts/update-linux-headers.sh
> >
> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > ---
> >  scripts/checkpatch.pl | 14 ++++++++++++--
> >  1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index ff373a7083..b0e8266fa2 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -1374,6 +1374,7 @@ sub process {
> >         my $in_header_lines = $file ? 0 : 1;
> >         my $in_commit_log = 0;          #Scanning lines before patch
> >         my $reported_maintainer_file = 0;
> > +       my $reported_imported_file = 0;
> >         my $non_utf8_charset = 0;
> >
> >         our @report = ();
> > @@ -1673,8 +1674,17 @@ sub process {
> >  # ignore non-hunk lines and lines being removed
> >                 next if (!$hunk_line || $line =~ /^-/);
> >
> > -# ignore files that are being periodically imported from Linux
> > -               next if ($realfile =~ 
> > /^(linux-headers|include\/standard-headers)\//);
> > +# ignore files that are being periodically imported from Linux and emit a 
> > warning
> > +               if ($realfile =~ 
> > /^(linux-headers|include\/standard-headers)\//) {
> > +                       if (!$reported_imported_file) {
> > +                               $reported_imported_file = 1;
> > +                               WARN("added, moved or deleted file(s) " .
> > +                                    "imported from Linux, are you using " .
> > +                                    "scripts/update-linux-headers.sh?\n" .
> > +                                    $herecurr);
> > +                       }
> > +                       next;
> > +               }
>
> Thanks, that looks useful -- just two comments (sorry, my perl-fu is
> low):

Same perl-fu here ;-P

> - Is there a way to check that this is a proper linux headers update?
>  We'd have to rely on heuristics, but OTOH, we also usually want a
>  headers update to use a certain format ($SUBJECT containing "headers
>  update", patch description pointing to the version this update was
>  done against.) Not sure if it is worth actually trying to figure this
>  out.

I think it can be done though I think we should formalize it somewhere 
first, or integrate the generation of the commit in the 
scripts/update-linux-headers.sh

At that point here we can add a check based on that.

> - A common issue is headers changes mixed in with other code changes,
>  which should not happen -- can we check for that as well and advise
>  to either do a headers update, or use a placeholder patch?

Yeah, Daniel suggested the same, I'll address in v2.

Thanks,
Stefano