Where does copying end though?
If an AI "retypes" it, not only with some variable renaming but some transformations that are not just describable by a few code transformations (neural nets are really not transparent and can do weird stuff), it wouldn't seem like a copy when just comparing parts of it, but it effectively would be one, as it was an automated translation.
Probably, copying ends when the original creative elements are unrecognizable. Renaming variables actually goes a long way to that, also having different or standardized (and therefore not creative) whitespace conventions, not copying high level structure of files, etc.
The functional parts of code are not copyrightable, only the non functional creative elements.
> The functional parts of code are not copyrightable, only the non functional creative elements.
1. Depends heavily on the jurisdiction (e.g., Software patents are a thing in America but not really in basically all European ones)
2. A change to a copyrightable work, creative or not, would still mean that you created a derived work where you'd hold some additional rights, depending on the original license, but not that it would now be only in your creative possession.
E.g., check §5 of https://www.gnu.org/licenses/gpl-3.0.en.html
3. What do you think of when saying "functional parts"? Some basic code structure like an `if () {} else {}` -> sure, but anything algorithmic like can be seen as copyrightable, and whatever (creative or not) transformation you apply, in its basics it is a derived work, that's just a fact and the definition of derived work.
Now, would that matter in courts? That depends not only on 1., but additionally to that also very much on the specific case, and for most trivial like it probably would be ruled out, but if an org would invest enough lawyer power, or suing in a for its case favourable court (OLG Hamburg anyone). Most small stuff would be thrown out as not substantial enough, or die even before reaching any court.
But, that actually scares me a bit when thinking about that in this context, as for me, it seems like when assuming you'd be right, this all would significantly erodes the power of copyleft licenses like (A)GPL.
Especially if a non-transparent (e.g., AI), lets call it, code laundry would be deemed as a lawful way to strip out copyright. As it is non-transparent it wouldn't be immediately clear if creative change or not, to use the criteria for copyright you used. This would break basically the whole FOSS community, and with its all major projects (Linux, coreutils, ansible, git, word press, just to name a few) basically 80% of core infrastructure.
