Re: Can I use CRoaring library in Git?

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Thu, Jul 21 2022, Abhradeep Chakraborty wrote:

> On Thu, Jul 21, 2022 at 7:29 PM Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
>>
>> It's great that the primary author of the library wants to release it
>> under a compatible license.
>>
>> But I feel like I'm missing something here, don't we still need the
>> other contributors to that code to sign off on such a license change,
>> and for us to be comfortable with integrating such code?
>
> As far as I see their commits, they don't use sign-off in any of their commits.

That's unrelated, that's just a convention linux.git & git.git (and
maybe some others) use to mean "I pinky promise this is my work, or can
be licensed under the project terms".

It doesn't impact how copyright or software licencing works in general.

> I know what you want to mean but the license text uses "The CRoaring
> authors" rather than "Daniel Lemire". Below is the text -
>
>     /*
>     * MIT License
>     *
>     * Copyright 2016-2022 The CRoaring authors
>    *
>    * Permission is hereby granted, free of charge, to any
>    * person obtaining a copy of this software and associated
>      ...
>    */
>
> So, isn't it enough for us?

That's a commonly used shorthand for not having to exhaustively list all
authors everywhere, but it's unrelated to the process by which
dual-licencing can happen after the fact.

If you and I come up with a 1000 line file together (each contributing
500 lines) and it says "copyright <this file's authors> and we license
it under the GPLv3" that doesn't give either of us permission to then
re-license the work later without the other copyright holder's approval.

>> My understanding (again, not a lawyer and all that) is that such
>> transitions happen one of a few ways:
>>
>>  A. One entity had been assigned copyright in the first place, and can
>>     re-license the work. E.g. the FSF requiring copyright assignments
>>     for anything non-trivial.
>>
>>  B. The license itself has an "upgrade" clause (e.g. GPLv2 "or later"
>>     projects being GPLv3 compatible).
>>
>>  C. All copyright holders (or near enough) agree to
>>     relicense. E.g. OpenStreetMap went through this process at some
>>     point.
>
> I got your point here. I am sure that "All copyright holders" have no
> problem with this relicensing.

Yes, that seems unlikely in practice. But I'm asking because it's not
obvious from the linked-to discussion that anyone except the primary
author decided this.

So if we integrate it into git.git and one of those people /would/ have
a problem with it we'd be the ones in trouble.

> Daniel already said in his comment[1] that they do not have any problem with it.
>
> [1] https://groups.google.com/g/roaring-bitmaps/c/0d7KoA79k3A/m/t8e09-wPAgAJ

Anyway, I don't see much of a point in two non-lawyers continuing this
discussion, I just asked in case there was something obvious I was
missing. E.g. the primary author is a professor, perhaps all (or
substantial amount of) the contributors were students at the same
university, and some copyright assignment etc. happened behind the
scenes.

I think it would be prudent if/when we decide to integrate this code to
ask our contacts at the SFC to give this a once-over, luckily we do have
actual laywers to call on if needed :)