Choosing a license for a software package

[smolloy]

Hi all,
I'm nearing the first release of a set of Python modules that I hope to encourage others in my field to use, and I'm having trouble navigating the huge number of possible free licenses.

I know that a full recommendation can only be made by a lawyer, and I know that you may not be fully comfortable making a recommendation to me, but I would still appreciate your thoughts.

The goals of my software are that it always remains free and open (in the FSF senses of those words), and that any extensions also remain free. For example, I want students to be able to use it for calculations without having ever having to purchase (or apply for) a license, and I want any extensions written by that student (*if* they inherit from any of my classes) to exist under the same license.

I don't mind if my code is included in a larger, proprietary, project, just as long as I get credit where it is due, and that any extensions they write (just like the student) become free.

This sounds to me like a BSD license, but I'd love to hear people's thoughts. Are there drawbacks to the BSD license (GPL fans can tell me what they think!)? Should I be thinking of the GPLv3 instead (BSD fans, now it's your turn!)?

Let me know what you think, and please keep it civil!

[darkrose0510]

I think the LGPL might be what you're after, as it's a free license, allows use of the code in a proprietary project, but extensions/modifications to the actual code must be licensed unser the LGPL too.

I may not have that 100% right, but pretty sure that's the gist of it.

[GNU-Fan]

Hi,

This sounds to me like a BSD license, but I'd love to hear people's thoughts. Are there drawbacks to the BSD license (GPL fans can tell me what they think!)?

If you use a BSD license without the advertising clause the software you distribute is Free Software. Please note however that the BSD offers no protection at all against proprietarization further downstream. It merely asks to give credit. It is no copyleft license.

Should I be thinking of the GPLv3 instead (BSD fans, now it's your turn!)?

The GPLv3 is a very strong copyleft. It demands that every distributor who uses the code of such a package can only distribute under the same GPL license (or, optionally, any later).


The LGPL, as it has been suggested, is somewhat in the middle. You can distribute proprietary applications which link dynamically to it. But one still needs to offer the source for the library itself including any modifications if one distributes.

So I second that you would most likely wish to use the LGPL if I understand you correctly.

Here is an overview and some words of opinion about many licenses:
Various Licenses and Comments about Them - GNU Project - Free Software Foundation (FSF)
Why you shouldn't use the Lesser GPL for your next library - GNU Project - Free Software Foundation (FSF)
Frequently Asked Questions about the GNU Licenses - GNU Project - Free Software Foundation (FSF)

[smolloy]

Thanks for your opinions guys.

I was thinking about the LGPL, but wy understanding was that it was primarily written for C/C++ libraries. Do you know if it's applicable for Python as well?

I've started going off the BSD license and am veering towards GPLv3, but would still value any other advice.

[GNU-Fan]

Thanks for your opinions guys.
I was thinking about the LGPL, but wy understanding was that it was primarily written for C/C++ libraries. Do you know if it's applicable for Python as well?

Yes. I don't see a reason why it shouldn't.