Subject: Re: Embedding Git Command Line

From: "brian m. carlson" <[email-masked]>
Date: Thu, 16 May 2024 15:15:27 +0000

On 2024-05-16 at 12:04:35, Kevin Gale wrote:
> Hi.

Hey,

> What I would like to know is if integrating with the command line tools would still fall foul of the GPLv2 license or if there is an exception like there is for libgit2.

First of all, I'm not a lawyer and this is not legal advice.  However,
having said that, I think the common understanding is that it's fine to
call out to a GPL binary from your proprietary program without violating
the license, unless the output is a derivative work.  Usually that's not
the case; it would only usually be so if the output included part of the
GPL software's source code, such as a parser generator.  The FSF has a
FAQ[0] that covers this to some extent, which calls the approach of
calling out to the program a form of "communicat[ing] at arms length".

As a major copyright holder in Git, I don't see a problem from my
perspective with a proprietary piece of software calling out to Git as a
separate binary.  Git is designed to provide scripting interfaces so
it's easy to use from a variety of software.  You would of course need
to provide the source to the version of Git you distribute and the
copyright and license information as well, in compliance with the
license.  Note also that if you are distributing Git, you cannot link it
against GPL-incompatible software (e.g., OpenSSL) unless that
GPL-incompatible software is distributed independently as part of the
operating system.

I also want to be clear that this is my understanding as a layperson and
my interpretation as a contributor to and copyright holder in Git, but
it isn't binding on anyone else here.  If you want a legal opinion, you
need to consult a lawyer licensed in your jurisdiction who has
experience in FLOSS copyright law.  Nobody here can provide you such
an opinion.

[0] https://www.gnu.org/licenses/gpl-faq.html#GPLInProprietarySystem
-- 
brian m. carlson (they/them or he/him)
Toronto, Ontario, CA