Licensing

[travcunn]

The licensing of this module may prevent MIT/BSD licensed modules from being used to make improvements. GPL doesn't play nicely with them. May I suggest something a bit more permissive, such as MIT?

[rasbt]

When I understand correctly, GPL wouldn't interfere with improvements, the only catch is that they have to be open-sourced, too, right? (Which would be a good thing btw)

[travcunn]

For example, it would be nice to be able to use the popular "requests" or "sqlalchemy" modules to improve this program, but the GPL states that the other software must be GPL licensed. Both of those libraries are already open source using other licenses. In this case, the GPL is actually preventing other open source libraries from being used. I don't have time to rewrite the "requests" or "sqlalchemy" module under a different license.

[rasbt]

Sorry, but I didn't see any paragraph in GPL that would forbid to use other open source code. But I am seriously curious about it now, would be nice if you could inform me about
that paragraph to avoid any violences here

[rhiever]

@travcunn, can you please quote the paragraph that states this? I'll need to look into this further.

[travcunn]

I'm not an expert, but this blog post explains gpl vs bsd: http://lucumr.pocoo.org/2009/2/12/are-you-sure-you-want-to-use-gpl/

If GPL is the way you want to go, then I support you, but hopefully I informed you of other options.

[rasbt]

Dunno what to make of this blog post... He could have provided some paragraphs to underline his statements...But I think I understand the issue here: "BSD is GPL compatible, but GPL does not permit the use of GPL licensed code in non-GPL code. "
So, if you write your code it wouldn't be a problem to distribute it if you license it under GPL, the only problem is that the other modules ("requests", "sqlalchemy") may not be okay with it if you license the work under GPL...

[leafstorm]

You can use MIT/BSD-licensed software in GPL-licensed software without problems. When you use software as part of other software, you are effectively relicensing all of it under the main software's license. The GPL's distribution terms don't break anything in those licenses, because it's completely OK with you putting their copyright statements in. (This is why MIT/BSD software can also be used in proprietary software...the whole work gets licensed as proprietary.)

The reason you can't use GPL software in MIT/BSD software is because relicensing GPL software under a license that says, "you don't have to release your derivatives under the GPL if you distribute them," would prevent the GPL's license requirements from carrying out.

So, Requests or SQLAlchemy would be completely fine with being incorporated into a GPL codebase. All their licenses care about is you including their copyright statement.

Making changes to Requests and SQLAlchemy, then integrating them in, would still be OK, because your changes could still be MIT/BSD-licensed. However, if you somehow built twitter-follow-bot into Requests (not sure why you would want to do this, but OK) you would have to release your modified Requests under the GPL so that all of twitter-follow-bot's license requirements would be carried out in the combined Requests. The original Requests would be completely fine though.

(TL;DR: Licensing requirements aren't symmetric. ;-) )

[rhiever]

This is what I thought. Thanks for the explanation, @leafstorm.

I intend to stick with GPL for now, but will re-evaluate the other licenses soon.