GPL License Question

[Byron]

Hi,

As the answer to this question might be interesting for others as well, I make it public using the issue system.

Pygit2 uses the same license as libgit2, the GPL with linkage exception. The problem I see is that this exception doesn't apply to the usage of pygit2 within other python programs and libraries which are not necessarily licensed under GPL.

For instance, I would be interested in using pygit2 in one of my projects, gitdb, which in turn can be used by git-python. Both are licensed under NewBSD, so I am worried that using pygit2 would compromise this license and force it into the GPL.

Could you please clarify the situation ?
Thank you,
Sebastian

[jdavid]

I don't like the "GPLv2 + exception" for pygit2 either. Personally I would prefer LGPLv3, that would be fine to you?

To change the license the agreement of everybody that contributed to pygit2 is required, starting by Dave Borowitz, who has written more than half of it.

[Byron]

According to wikipedia, the LGPL, even though it usually refers to library linking, may also be generalized into 'using' the library.
As python doesn't explicitly link pygit2 when importing it, the LGPL wouldn't really help unless we just regard pygit2 as being 'used' by my library. I don't know what lawyers say about that, but I would be fine with LGPL, from what I read in the wiki at least.

Personally I think the LGPL was designed just with dynamic and static libraries in mind, but maybe it can be widened to the general use of one library by another, no matter which system of linkage is actually employed.

Maybe it would already be enough to adjust the linkage exemption to state that it may be linked to and imported. This should be clear enough to allow git-python to use it.

[dborowitz]

On Thu, Mar 31, 2011 at 03:27, Byron <
reply@reply.github.com>wrote:

Hi,

As the answer to this question might be interesting for others as well, I
make it public using the issue system.

Pygit2 uses the same license as libgit2, the GPL with linkage exception.
The problem I see is that this exception doesn't apply to the usage of
pygit2 within other python programs and libraries which are not necessarily
licensed under GPL.

I've been assured by a lawyer that the linkage exception does apply to the
normal Python import mechanism. So you can safely "import pygit2" from a BSD
project without making that project GPL+exception. (You still cannot safely
incorporate pygit2 source code in the source of a BSD project.)

For instance, I would be interested in using pygit2 in one of my projects,
gitdb, which in turn can be used by git-python. Both are licensed under
NewBSD, so I am worried that using pygit2 would compromise this license and
force it into the GPL.

As long as "using" == "importing", this is fine.

Could you please clarify the situation ?
Thank you,
Sebastian

Reply to this email directly or view it on GitHub:
#15

[Byron]

Great to hear, thanks !
I am quite eager to find out how libgit2 performs within the git-python streaming framework, so I will try to implement a gitdb which allows to obtain object information and object streams. Lets see how that works out :).

[vmg]

Hey, just stepping by to remind you that the linking exception is indeed very permissive: you could even link your own Python library with a static version of libgit2 without it affecting your own program's license. I'm looking forward to see what can you come up with the git-python streaming framework.