[rcthompson]

If I am the sole owner of a work, I can change the license of newly distributed copies from any previous license to any new license that I want to, even if the new license is more restrictive. The new license doesn't retroactively apply to copies that were distributed under the old license, only new copies distributed under the new license.

However, my original question still stands. If I hack privately on a git repo and never distribute it, and then I only add a license in commit N right before first releasing it publicly, what is the license of commits 1 through N-1, which do not contain a license themselves (or perhaps contain a different license) but were never distributed separately from the license contained in commit N?

[merijnv]

Unspecified, so legally murky. But there's a notion of "implied license", so someone using the code could argue that "openly putting it somewhere publicly" constitutes and implicit license grant.

Note by the way that you are ALREADY explicitly granting some rights by putting it on GitHub:

We claim no intellectual property rights over the material you provide to the Service. Your profile and materials uploaded remain yours. However, by setting your pages to be viewed publicly, you agree to allow others to view your Content. By setting your repositories to be viewed publicly, you agree to allow others to view and fork your repositories.

Arguing that this constitutes an implicit license to use this code probably wouldn't be too hard. However trying to relicense/redistribute is less likely. In the end this will have to be decided by a judge in court.

[raoulduke]

I'm a law student but not an expert, and I haven't researched the caselaw (yet?). Rcthompson, I apologize for taking this opportunity to go way beyond your question (see below). [This also reflects my assumption that you are coding within the US. And also this is not legal advice, merely hypothetical musing.]

Whatever you write, if copyrightable, automatically achieves copyright protection when fixed in tangible form - and you automatically obtain authorship rights. That gives you the right to grant licenses for any of the rights you've obtained (including to produce derivative works). Swift's license (https://swift.org/LICENSE.txt) allows you to modify the license of your additions (your right under federal law anyway), but not the sections you didn't author.

I mean... I can see it cutting both ways. On its face, it's a very fair system - you can use whatever you want but only own whatever you wrote. What becomes problematic is if companies (realistically) with wide distribution nets grab open-source code, modify it slightly, alter the license of the bundle and resell it. I know that's not a new phenomenon.

Another concern I see is if libraries or maybe files or something have proprietary names, then in theory you'd require an express license from the proprietor (in this case basically Apple).

I was concerned I didn't understand the basic question that prompted my response, which was from rcthompson, but he reframed it: commits 1 to n-1 have sort of Schrodinger's Cat licenses. They have copyright protection (regardless of any of this). And that grants you the right to control licensing of those rights (reproduction, public display, derivative works, etc.). But I don't see why you couldn't retroactively apply whatever you want. The Swift license applies itself, if you don't specify otherwise, upon submission of your work to the licensor (I guess per notice requirements). Until then it's unclear. However, federal copyright protections and state common and statutory laws would also apply (and would basically grant you the right to control licensing).

[swhipple]

It depends on how the license was intended to be applied.

If you're the sole owner and declare the entire repository contents under XYZ, the previous commits would be available under the license, regardless of the actual commit that adds the license file. If you declare a specific revision under XYZ, then only that revision is under the license.

A different example is the case of a repository with many copyright holders changing the license, and not being able to drag all the previous code into the newly licensed version. You wouldn't be able to take all the commits in history under the terms of the new license.