Embedding Git Command Line

Hi.

We are looking to embed version control features into our commercially licensed proprietary product.

We haven’t made a decision on which technology yet but Git would be a popular choice.

I’ve read ‘Appendix B: Embedding Git in your applications’ on the website and determined that our choices would be either to invoke the Git command line tools or integrate with libgit2.

In theory, the command line tools should be easier to integrate with and we would rely on the user’s Git install rather than bundling the Git software.

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.

TIA Kevin

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

Hey,

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

On Thu, May 16, 2024 at 01:04:35PM +0100, Kevin Gale wrote:

[...]

While only tangentially related, I'd point out that if your product is going to actually _bundle_ Git, then be prepared that it has quite a hefty set of dependencies, so unless you're going to rely on the target OS to provide them (which is, as I understand it, a no-go on Windows) you might be required to invest considerable effort into that endaevor.

On the other hand, if it's not a shrink-wrap product but rather something enterprise-y (kind of software usually installed by a dedicated technician - as opposed to being downloaded and click-through installing by a layperson), you might just use what Git for Windows ships, I suppose.

Hi,

On Thu, 16 May 2024, Konstantin Khomoutov wrote:

Git for Windows offers MinGit (for full details, see https://github.com/git-for-windows/git/wiki/MinGit), which is a subset of Git for Windows intended to be bundled by 3rd-party applications. That's what Visual Studio and GitHub Desktop do.

Ciao, Johannes

On Sat, May 18, 2024 at 09:50:00PM +0200, Johannes Schindelin wrote:

[...]

I've read that page and a couple related (describing MSYS[2] vs MinGW stuff and the like) - pretty impressive. Thanks for the heads-up!