Re: [PATCH] checkpatch: use patch subject when reading from stdin

[Geert Uytterhoeven]

Hi Joe,

On Tue, Oct 8, 2019 at 7:02 PM Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Tue, 2019-10-08 at 17:28 +0200, Geert Uytterhoeven wrote:
> > On Tue, Oct 8, 2019 at 5:20 PM Joe Perches <joe@xxxxxxxxxxx> wrote:
> > > On Tue, 2019-10-08 at 11:40 +0200, Geert Uytterhoeven wrote:
> > > > When reading a patch file from standard input, checkpatch calls it "Your
> > > > patch", and reports its state as:
> > > >
> > > >     Your patch has style problems, please review.
> > > >
> > > > or:
> > > >
> > > >     Your patch has no obvious style problems and is ready for submission.
> > > >
> > > > Hence when checking multiple patches by piping them to checkpatch, e.g.
> > > > when checking patchwork bundles using:
> > > >
> > > >     formail -s scripts/checkpatch.pl < bundle-foo.mbox
> > > >
> > > > it is difficult to identify which patches need to be reviewed and
> > > > improved.
> > > >
> > > > Fix this by replacing "Your patch" by the patch subject, if present.
> > > []
> > > > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > > []
> > > > @@ -1047,6 +1047,10 @@ for my $filename (@ARGV) {
> > > >       }
> > > >       while (<$FILE>) {
> > > >               chomp;
> > > > +             if ($vname eq 'Your patch') {
> > > > +                     my ($subject) = $_ =~ /^Subject:\s*(.*)/;
> > > > +                     $vname = '"' . $subject . '"' if $subject;
> > >
> > > Hi again Geert.
> > >
> > > Just some stylistic nits:
> > >
> > > $filename is not quoted so I think adding quotes
> > > before and after $subject may not be useful.
> >
> > Filename is indeed not quoted, but $git_commits{$filename} is.
>
> If I understand your use case, this will only show the last
> patch $subject of a bundle?

False.
"formail -s scripts/checkpatch.pl < bundle-foo.mbox" splits
"bundle-foo.mbox" in separate patches, and invokes
"scripts/checkpatch.pl" for each of them.

> Also, it'll show things like "duplicate signature" when multiple
> patches are tested in a single bundle.

False, due to the splitting by formail.

> For instance, if I have a git format-patch series in an output
> directory and do
>
> $ cat <output_dir>/*.patch | ./scripts/checkpatch.pl
>
> Bad output happen.

Yeah, because you're concatenating all patches.
Currently it works for single patches only.

> Maybe this might be better:

> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2444,6 +2444,15 @@ sub process {
>
>                 my $rawline = $rawlines[$linenr - 1];
>
> +# if input from stdin, report the subject lines if they exist
> +               if ($filename eq '-' && !$quiet &&
> +                   $rawline =~ /^Subject:\s*(.*)/) {
> +                       report("stdin", "STDIN", '-' x length($1));
> +                       report("stdin", "STDIN", $1);
> +                       report("stdin", "STDIN", '-' x length($1));
> +                       %signatures = ();       # avoid duplicate signatures
> +               }
> +
>  # check if it's a mode change, rename or start of a patch
>                 if (!$in_commit_log &&
>                     ($line =~ /^ mode change [0-7]+ => [0-7]+ \S+\s*$/ ||

Perhaps.  Just passing the patchwork bundle to checkpatch, and fixing
checkpatch to handle multiple patches in a single file was my first idea.
But it looked fragile, with too much state that needs to be reset.
I.e. the state is not limited to %signatures.  You also have to reset
$author inside process(), and probably a dozen other variables.
And make sure that future changes don't forget resetting all newly
introduced variables.

Hence I settled for the solution using formail.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds