Re: Can I use CRoaring library in Git?

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

On Mon, Jul 18 2022, Abhradeep Chakraborty wrote:

> On Mon, Jul 18, 2022 at 4:43 PM Jakub Narębski <jnareb@gmail.com> wrote:
>>
>> Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com> writes:
>>
>> > Hello,
>> >
>> > I need the CRoaring[1] library to use roaring bitmaps. But it has
>> > Apache license v2 which is not compatible with GPLv2[2].
>>
>> Actually Apache License v2.0 *is* compatibile with GPLv2 and GPLv3
>> in the sense that you can include the Apache licensed code (like the
>> CRoaring library) in the GPLv2 project (like Git).
>>
>> Quote from the cited "Apache License V2.0 and GPL Compatibility"[2]:
>>
>>   The Free Software Foundation considers the Apache License, Version 2.0
>>   to be a free software license, compatible with version 3 of the GPL.
>>   The Software Freedom Law Center provides practical advice for
>>   developers about including permissively licensed source.
>>
>>   Apache 2 software can therefore be included in GPLv3 projects, because
>>   the GPLv3 license accepts our software into GPLv3 works. However,
>>   GPLv3 software cannot be included in Apache projects. The licenses are
>>   incompatible in one direction only, and it is a result of ASF's
>>   licensing philosophy and the GPLv3 authors' interpretation of
>>   copyright law.
>
> But the same article also says  -
>
>   Despite our best efforts, the FSF has never considered the Apache License
>   to be compatible with GPL version 2, citing the patent termination
> and indemnification
>   provisions as restrictions not present in the older GPL license. The
> Apache Software
>   Foundation believes that you should always try to obey the
> constraints expressed by
>   the copyright holder when redistributing their work.

...indeed, and for those that don't remember around the time the GPLv3
was being discussed & eventually released having it be compatible with
the Apache license was a major thing that the Apache Foundation and FSF
worked towards.

But we use GPLv2 only, which as you note is explicitly known to be
incompatible with Apache v2.0.