Re: [PATCH 2/3] scripts: validate SPDX license choices

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Oct 07, 2024 at 11:19:15AM -0500, Brian Cain wrote:
> 
> On 10/7/2024 10:45 AM, Daniel P. Berrangé wrote:
> > We expect all new code to be contributed with the "GPL-2.0-or-later"
> > license tag. Divergance is permitted if the new file is derived from
> > pre-existing code under a different license, whether from elsewhere
> > in QEMU codebase, or outside.
> > 
> > Issue a warning if the declared license is not "GPL-2.0-or-later",
> > and an error if the license is not one of the handful of the
> > expected licenses to prevent unintended proliferation.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >   scripts/checkpatch.pl | 66 +++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 66 insertions(+)
> > 
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index cc266abdcd..cd1ed90f4c 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -1353,6 +1353,67 @@ sub checkfilename {
> >   	}
> >   }
> > +sub checkspdx {
> > +    my ($file, $expr) = @_;
> > +
> > +    # Imported Linux headers probably have SPDX tags, but if they
> > +    # don't we're not requiring contributors to fix this
> > +    if ($file =~ m,include/standard-headers, ||
> > +	$file =~ m,linux-headers,) {
> > +	return;
> > +    }
> > +
> > +    my $origexpr = $expr;
> > +
> > +    # Flatten sub-expressions
> > +    $expr =~ s/\(|\)/ /g;
> > +    $expr =~ s/OR|AND/ /g;
> > +
> > +    # Merge WITH exceptions to the license
> > +    $expr =~ s/\s+WITH\s+/-WITH-/g;
> > +
> > +    # Cull more leading/trailing whitespace
> > +    $expr =~ s/^\s*//g;
> > +    $expr =~ s/\s*$//g;
> > +
> > +    my @bits = split / +/, $expr;
> > +
> > +    my $prefer = "GPL-2.0-or-later";
> > +    my @valid = qw(
> > +	LGPL-2.0-or-later
> > +	LGPL-2.1-or-later
> > +	GPL-2.0-only
> > +	LGPL-2.0-only
> > +	LGPL-2.0-only
> > +	BSD-2-Clause
> > +	BSD-3-Clause
> > +	MIT
> > +	);
> > +
> > +    my $nonpreferred = 0;
> > +    my @unknown = ();
> > +    foreach my $bit (@bits) {
> > +	if ($bit eq $prefer) {
> > +	    next;
> > +	}
> > +	if (grep /^$bit$/, @valid) {
> > +	    $nonpreferred = 1;
> > +	} else {
> > +	    push @unknown, $bit;
> > +	}
> > +    }
> > +    if (@unknown) {
> > +	ERROR("Saw unacceptable licenses '" . join(',', @unknown) .
> > +	      "', valid choices for QEMU are:\n" . join("\n", $prefer, @valid));
> > +    }
> > +
> > +    if ($nonpreferred) {
> > +	WARN("Saw acceptable license '$origexpr' but note '$prefer' is preferred " .
> > +	     "for new files unless the code is derived from a source with an" .
> > +	     "existed declared license that must be followed.");
> 
> Is it not preferred to contribute code under the BSD-3-clause? Based on
> other items in the project, I was expecting we could make contributions for
> hexagon w/BSD.  But those are exceptional cases and not to be followed in
> the general case?

I'm not saying people can't contribute under BSD, but if that is required,
a explanation of why is desired.

IMHO we don't want contributors choosing an non-GPL-2.0-or-later license
merely out of personal (or corporate) preferences.

We want GPL-2.0-or-later to be used for everything, unless there is a
compelling reason to diverge. The need to remain compliant with existing
code that has been incorporated is the most common & obvious reason for
this.

Other reasons likely exist - which could be explained in the commit
message, to aid reviewers who are likely to see the checkpatch warnings
about the unusal license choices.

With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|