Re: Clarify the license field of the package

[Maxime Devos]

On 22-08-2022 11:02, 宋文武 wrote:

> Hello list, I have some questions about the 'license' of a package,
> currently defined as:
>
>      The license of the package; a value from ‘(guix licenses)’, or a
>      list of such values.
>
> 1. It's the license of source files (guix build -S) or built binary
>     files?

(If 'built binary files', I would include generated or copied 
documentation in the list. And icons, .desktop files, ..., I'm not 
restricting myself to _executable_ binaries here and also not to 
binaries that aren't sources as well.)

Rarely, there is some weirdness where the source code is free 
(VSCodium?) but the official build has a non-free license (VSCode?). At 
least for that example, it doesn't apply to Guix though (because 
VSCodium is not packaged, and because with some rare exceptions we build 
from source).

However, in my experience, in free software they almost always have the 
same license, so the distinction appears meaningless to me with the 
possible exception of build scripts and test files (including, but not 
limited to, test code).

I think it should include the source files, as the license of the source 
is important for people doing 'guix build --source'.

> 2. When its value is a list of multiple licenses, it's files under
>     different licenses (eg: lib/*.so under LGPL, while bin/* under GPL),
>     or files under one license select from choices?
>
> My guess is that the license field is for source files since we can
> disable binary substitutes, and list is used for files under different
> licenses.
>
> Does my guess is correct?  Thank you!

As answered in a reply to a patch, myself I go for 'files under 
different licenses' -- to me it seems hard to go wrong with 'just 
include all participating licenses' instead of trying to make a selection.

However, keep in mind that sometimes a file is part licensed as, say, 
BSD(*), part as Expat, with modifications under the GPL -- to me it 
appears that for practical purposes you could consider such a thing to 
be 'effectively GPL', but that's not 100% accurate, as it appears 
required to preserve the BSD and Expat license text. (Such things can 
happen when incorporating code from other, differently-licensed, projects).

(*) let's say without the advertising clause or whatever it was (IIRC 
and IIUC the original BSD was incompatible with the GPL?).

If there's some consensus, I think it would be nice to clarify this 
matter in the manual.

Greetings,
Maxime.

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