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Re: Use of License-Reference in debian/copyright allowed?



Quoting Sam Hartman (2022-01-17 03:48:40)
> >>>>> "Jonas" == Jonas Smedegaard <jonas@jones.dk> writes:
> 
>     Jonas> Please note, however, that license _grants_ (i.e. the various
>     Jonas> ways a copyright holder can state that they grant some
>     Jonas> _referenced-by-them_ license) need not be included verbatim.
> 
> I suspect we're in agreement.  But for completeness.  If a copyright 
> grant simply grants the terms of a referenced license, I don't think 
> we need to include it verbatim.  However, if the grant includes 
> licensing itself--for example additional permissions or even more 
> interestingly restrictions), it's easy for the grant to become more of 
> a license and to be a license that needs to binclude in its own right.
> 
> (I'm aware that many circumstances where a license grant includes a 
> restriction would be problematic especially say when combined with the 
> GPL-3.  I can think of licenses/situations when such a result would 
> still be DFSG free though, and in such situations it seems like it 
> would be important to clearly document in debian/copyright).
> 
> I don't think anything I write above is a disagreement with the common 
> case you're covering.  I suspect you already would be, but my advice 
> to others is to be careful of license grants that include unsual text 
> and to err on the side of including them in debian/copyright.

Yes, we are in agreement.

Thanks for elaborating on that, Sam.  I agree that not mentioning it 
might give a misleading impression.

What I intended to say (but was not really clear) is that the thing I 
place as a License-Grant is text that *only* references another license 
text without adding *any* legal clauses (restrictions, permissions, 
disclaimers) besides those covered in the referenced license text.

What I didn't say previously but maybe helps make sense of it, is that 
despite license grants containing no legal _clauses_ they do have that 
one important feature of tying things together: A license is in effect 
not when it exists in a package but when granted by a copyright holder.

A tarball containing code and a file named LICENSE containing e.g. GPLv2 
does not mean that everything in that tarball has been granted the GPLv2 
license by its copyright holders.  Possibly it does, but the act of 
adding a LICENSE file is a very weak way of stating that connection.  A 
strong way is adding a sentence in each copyright-protected file.  And 
_that_ is the reason it makes sense to track both grants and fulltexts.

(this is similar to a reason it makes sense to list copyright holders 
even though some licenses do not require it: only copyright holders can 
grant a license, so identifying them is relevant for _resolving_ license 
even if sometimes not required to _comply_ with the license)

I recommend to list *both* license fulltexts *and* license grants in 
debian/copyright (even though only license fulltexts are required). 
Doing that helps helps understand how you concluded a certain license 
fulltext is in effect.  My writing style is to *only* write license 
fulltexts (i.e. legal clauses - what is permitted and required and 
disclaimed) in License sections, and add add not-strictly-required 
license grants (i.e. purely references to fulltexts with *no* additional 
legal clauses) as License-Grant fields in Files sections.

(License-Grant is no an officially defined field, but adding unofficial 
fields is explicitly permitted in the copyright file format 1.0)

Here are a few examples (with most of the BSD fulltext snipped for 
brevity), from the ghostscript package which I kind-of use as reference 
for my writing style:

>>>>>

Files:
 Resource/CMap/*
Copyright:
  1990-2015  Adobe Systems Incorporated
License: BSD-3-Clause~Adobe

Files:
 contrib/pcl3/*
Copyright:
  1996-2003  Martin Lottermoser
License-Grant:
 pcl3 is free software and can be used
 under the terms of the GNU Lesser General Public License (LGPL),
 Version 2.1 (February 1999).
License: LGPL-2.1

License: BSD-3-Clause~Adobe
 Redistribution and use in source and binary forms,
 with or without modification,
 are permitted provided that the following conditions are met:
 .
 Redistributions of source code must retain
[...]
 .
 Redistributions in binary form must reproduce
[...]
 .
 Neither the name of Adobe Systems Incorporated
[...]

License: LGPL-2.1
Reference: /usr/share/common-licenses/LGPL-2.1

>>>>>

First Files section above has no License-Grant section - because 
BSD-style licenses are typically written in full, not referenced.

First License section contains the full license text *verbatim* - i.e. 
not the _generic_ BSD-3-Clause license but a slight deviation which 
covers a specific legal entity regardless if they are hold copyright or 
authored or contributed.

Second Files section contains a *verbatim* copy of the license grant - 
i.e. the actual phrase the author used to grant license of their work 
using a reusable "general public license".  There is no requirement from 
the author nor from the license nor from Debian in listing this text - 
but regardless it may help ftpmasters process your package faster 
because they can easier follow how you concluded that the LGPL-2.1 
license was involved.  And quite likely future releases of licensecheck 
will make use of License-Grant fields too, to help maintain - verify and 
update - debian/copyright files.

Second sample section above, I deviate from common practice in Debian: I 
put as License-Grant field in Files section what is more commonly put in 
a License section.

Second License section is essentially what triggered this email thread: 
Is it really ok to write such compact License fields?!?

Common practice is to put either license fulltext or license grant in 
the License section, mixeded with non-verbatim maintainer-authored notes 
- section 7.2 of the copright file format 1.0 specification even makes 
an example of putting a grant there and mixing in a custom note.

I find common practice quite confusing - I want the copyright file to 
clearly separate provenance - i.e. distinguish who said what.  I think 
that my introduction of fields License-Grant and Reference helps 
disambiguate.

Also for the concern you raise here, Sam, I think it helps to actively 
use new fields License-Grant and Reference: If I make a mistake, 
treating a text as a license grant not noticing that it contains license 
clauses on its own, then with common practice of mixing grant, fulltext 
and editorial notes together in a License section might hide the 
mistake, whereas explicitly stating "I read this as being just a grant" 
separate from "this is the license text granted by the copyright holder" 
separate from "over here Debian stores a verbatim copy of this license 
text" might help reveal such mistake.  By ftpmasters or fellow 
maintainers or users or tools.

 - Jonas

-- 
 * Jonas Smedegaard - idealist & Internet-arkitekt
 * Tlf.: +45 40843136  Website: http://dr.jones.dk/

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