Re: Clarify the license field of the package

[John Kehayias]

Hello 宋文武,

On Mon, Aug 22, 2022 at 05:02 PM, 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?
>

Not a lawyer by any means, so I'm not sure how it works. For sure it applies to 
the source, but after building the binary output will contain a LICENSE or 
COPYING file (always? I would assume). Other than that, I don't know :)

> 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?
>

In packaging, I have seen this when a package contains multiple sources for 
whatever reason, though we do try to unbundle as much as possible. I've also 
seen a few that just have multiple licenses as the source had specified 
multiple licenses, whether for different files or for user choice. Often, this 
is commented in the package definition for which license applies to which 
files, or why multiple are listed.

For example, in the recent haxe package (which I wrote and I believe you 
pushed), the compiler and standard library are packaged together with different 
licenses. This is noted in the comments of the license field. While it may be 
possible to package these separately, I'm not sure if it really makes sense 
given how they are used and what upstream intends.

> 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!

Those are my guesses/experiences above, hope that is helpful.

John