Forking / Cloning an active open source project

Question

I am looking at an open source project that handles OData calls against APIs. I'm thinking that it would make a great starting point for a new library aimed at an industry-specific API that is closely (but not exactly) based on OData that I will be working on.

As an open source developer, I have built quite a few libraries and apps, but I haven't borrowed from another project so directly before.

Is there a guide to

• properly crediting the original devs / library as I move forward
• ensuring the licenses are compatible (I'd probably stay with MIT, which is the original)
• letting the original team know what my intentions are and why I'm using their work?

I know what I'm proposing is strictly legal and within the scope of the open source movement, but I am curious if there's an accepted etiquette for these situations. I've had my code lifted wholesale and used in essentially identical projects that people are charging money for, and I don't want any misunderstanding like this.

Answer 1

I know what I'm proposing is strictly legal and within the scope of the open source movement, but I am curious if there's an accepted etiquette for these situations.

When you publish code under a licence, that licence expresses the sum total of your expectations of users. Since the code you're reusing is under the MIT licence, "the above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software", and that is the extent of the credit that's required. Because MIT is so permissive, your licence choice is very wide; but you've indicated you intend to stick with MIT, which is fine. As for contacting the original team, there is neither requirement for nor expectation of this, but it seems likely that they'd be interested to hear what people are doing with their code, so a note to the project mailing list, once you have something worth displaying, would probably be courteous.

I've had my code lifted wholesale and used in essentially identical projects that people are charging money for, and I don't want any misunderstanding like this.

If you published that code under a permissive free licence, it sounds to me like the misunderstanding was yours: you thought you hadn't given people the right to take your code and make money out of it, but you had. If you published it under a copyleft free licence, and the people who used it did so under an incompatible licence, then copyright infringement occurred, and you should take legal advice. But even the GPL has no problem with people selling free software (as long as they deliver freedom with it). There exist licences that look like free licences but forbid any commercial exploitation, but they are in fact non-free, and off-topic here.