Clarify licensing

[graue]

Hi! Nice library, thank you for making it and packaging it up.

You mention that it's based on code from https://github.com/martine/python-sourcemap. I'm not a lawyer, but I am pretty sure that this makes your library a derivative work, which means you must include @martine's copyright, a copy of the Apache license, and make a note of which parts of the code are by @martine (which would be covered by the Apache license instead of the BSD license). You'd probably be best off mentioning all of this in the LICENSE file and/or readme.

[mattrobenolt]

I don't know how this stuff works either. :)

Can you point me to explanations of how this stuff works? Maybe my derivative is different enough? By now, a lot of it has been changed and modified.

@martine, any input?

[graue]

If I had based my code on someone else's open-source code, I would simply leave intact their original copyright and the license they chose. That's always the safest option. Even a very small number of lines can be subject to copyright. When Oracle sued Google for copying Java code, the case eventually hinged on this almost trivial function.

The Apache license is a perfectly acceptable license, so I would just include it if I were you.

[mattrobenolt]

I guess what I'm asking is.. what is the proper way of doing this? I'm not trying to hide it, I just don't know how these things work.

I currently do this: https://github.com/mattrobenolt/python-sourcemap/blob/master/sourcemap/decoder.py#L5-L8

I'm linking to the original license. I'm not sure how using a license of something else, within in my project, affects my overarching license of BSD.

[graue]

Oh, I see. Basically the way it works is people have to comply with the Apache license when they use the parts of the code that @martine wrote, and they have to comply with the BSD license when they use the parts you wrote. If you've edited and integrated it so much that there is no real distinction between these two "parts", then people simply have to comply with both the BSD and Apache licenses when using this project. That's what you would want to say. Also include a copy of the relevant Apache license as LICENSE.Apache or something.

Edit: Also if you wanted to simplify things, you could relicense your own code under Apache so it's only one license. Everyone who uses your code has to comply with the Apache license either way.