Copyright can also apply to code rewritten in another programming language, if the overall structure and functionality is identical. Although tbh, that is a bit of a grey area, and in previous rulings there is some precedence that if the "translation" involves significant human effort then it can be considered to be sufficiently transformative. But promting an LLM to "rewrite this in Go" very likely doesn't pass that relatively high bar.

The study you linked is interesting (and likely underestimates the issue*), but it also shows that it is possible to automate detection of copyright infringing code in LLM output, and even just 2% is more than enough to open a case for malicious litigation. Large companies can write that off as the cost of doing business, but for small individual open-source developers this is a significant risk.

'*' Because human programmers usually reuse existing licensed code as libraries, while LLMs are prone to rewrite them, and as explained above a rewrite is at an elevated risk of being considered copyright infringing.

You are missing the point entirely. LLMs regularly generate code that is a near verbatim copy of existing copyrighted code, but with almost no way for the LLM using person to notice that. LLMs being sufficiently transformative might be an argument about the use of training material, making the resulting model not a copyright violation itself, and thus might protect the companies that produce and offer these models, but it says nothing about the actual output of a model.

It is only a question of time before some enterprising law firm decides to mass scan open-source projects and weaponize their findings similar to patent trolls or file-sharing legal threats. This has a long history in Germany where Codeberg is located, and even if a court rules that the host itself is only responsible for removing such copyright violating code, it will require significant effort to do so with constant legal fights as the attacking lawyers will try to figure out the identity of the person responsible so that they can blackmail them with cease and desist legal fees.

Politics will not care about some hobbyist open-source projects and large companies will spend a lot of effort to obfuscate their code to prevent this legal trolling to affect them.

There is a good chance that LLMs are sufficiently transformative that courts will decide they don't infringe the copyright of their sources.

How much money are you willing to put in to test that?

Well I left github because of "feels", reddit too.

I think slop-code & crypto can go there if they want, what are your "feelings" about that?