Re: [RFC PATCH] CODING_STYLE: Establish a policy with regards to copyright notices

[Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>]

On Wed Jan 28, 2026 at 8:04 AM CET, Jan Beulich wrote:
> On 27.01.2026 19:24, Alejandro Vallejo wrote:
>> This patch modifies CODING_STYLE to severely discourage use of copyright
>> notices when their presence is not legally mandatory.
>> 
>> Copyright notices are redundant on commit, misleading from the time the file
>> receives contributions from anyone not represented by such notice, and 
>> actively
>> harmful for attribution by the time the original code is long gone. They are
>> plain wrong when added on code motion.... the list goes on.
>> 
>> All attribution worth keeping is version-controlled through Signed-off-by,
>> Co-authored and the like, DCO and the cumulative contents of git history.
>> License banners have already been superseded by the contents of licenses/ and
>> SPDX tags.
>> 
>> Other FOSS projects have already moved away from explicit copyright notices
>> where possible, and severely discourage their use when not.
>> 
>> Apache and LLVM take active issue with copyrighted contributions and Chromium
>> takes issues with copyrighted contributions not attributed to the project. 
>> Some
>> Linux subsystem maintainers already frown upon copyright notices too, even if
>> it hasn't reached the point of being a mandated requirement yet.
>> 
>> Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@xxxxxxx>
>> ---
>> The actual changes are almost verbatim from the LLVM guideline, but it's not
>> exact. Wording can be adjusted as needed. I care about the core of the 
>> proposal.
>> Saying "please, drop the notice" on contributions where it's clearly not a
>> legal requirement, or have the contributor state that it is a legal 
>> requirement
>> and why.
>
> This "is a legal requirement" ...
>
>> --- a/CODING_STYLE
>> +++ b/CODING_STYLE
>> @@ -24,6 +24,24 @@ license, e.g.:
>>  
>>  See LICENSES/ for a list of licenses and SPDX tags currently used.
>>  
>> +Copyright notices
>> +-----------------
>> +
>> +Copyright for the code in the Xen Project is held by the respective
>> +contributors. Because you (or your company) retain ownership of the code you
>> +contribute, you know it may only be used under the terms of the open source
>> +license you contributed it under: the license for your contributions cannot 
>> be
>> +changed in the future without your approval.
>> +
>> +The Xen Project does not accept contributions that include in-source 
>> copyright
>> +notices except in the following cases:
>> +  * where a committed file already contains it.
>> +  * where a committed file is renamed.
>> +  * where such notices are on files from an external project being imported.
>
> ... may want (need?) reflecting as another bullet point here.

Hmmm. Yes, that would make sense.

>
> The wording of the first bullet point also can be taken to mean that adding to
> such pre-existing notices is acceptable. This may not be the intention?

Good point. That was very definitely not my intention.

The refinement also applies to the second bullet point, so I can add it as a
separate paragraph stating existing notices are to never be modified and only
removed with the express consent of the current holder(s).

------------------

Do you have a take for/against moving all existing notices to a separate NOTICES
file (a-la Apache). The existing file for them (in httpd) looks like this, so
they took the liberty to rewording the banners to be more digestible in single
file inclusion.

        Apache HTTP Server
        Copyright 2026 The Apache Software Foundation.

        This product includes software developed at
        The Apache Software Foundation (https://www.apache.org/).

        Portions of this software were developed at the National Center
        for Supercomputing Applications (NCSA) at the University of
        Illinois at Urbana-Champaign.

        This software contains code derived from the RSA Data Security
        Inc. MD5 Message-Digest Algorithm, including various
        modifications by Spyglass Inc., Carnegie Mellon University, and
        Bell Communications Research, Inc (Bellcore).

        This software contains code derived from the PCRE library pcreposix.c
        source code, written by Philip Hazel, Copyright 1997-2004
        by the University of Cambridge, England.

It'd blur the scope of existing holders, but code moves and so do their
contributions. Keeping a banner on a file after a refactor is just
misattribution.

------------------

In short. There's 1 question in 2 forms I'd like to have an answer to from a
core maintainers.

Would you be willing to ack a change along these lines?
  1. to a Copyright Notice policy within CODING_STYLE.
  2. to the relegation of existing notices to a NOTICES file in the style of
     Apache. Apache in particular mandates the file not be touched unless
     absolutely required for legal reasons.

(1) can be done without (2) if (2) proves to be "risky" in whatever legal way
it could possibly be risky.

Cheers,
Alejandro