"Impossible" is a tough standard to meet. But given how different idiomatic Java code and idiomatic Rust code are, it does seem kind of unlikely. I'd expect nothing at all would carry over from one codebase to the other even if you were making as straight a port as possible. Or alternatively one program would look like total garbage, like someone mechanically translating Lisp to C.
And indeed, with a quick browse through the Wire [0] and OWS [1] repositories I just can't find any kind of commonalities at all. Not in the structure, not in the comments, not in naming, not in the data structures, etc. Am I missing something, is there anything at all in the code itself that suggests the two codebases are related in any way at all? Or is the "GPL's OWS code" you refer to something else entirely?
That's exactly why I wrote "anything in the code itself". Yes, they made a mass commit adding that attribution to every file 9 days ago to conclude a messy lawsuit. That doesn't make the two codebases themselves appear any more related in isolation.
If there's GPL violation and code was copied, there should be some traces of that. Is it truly so unreasonable to ask what those traces were?
I hadn't heard about this case before, and so I don't know the details, but just from your own description, filing a preemptive lawsuit in response to an explicit copyright demand doesn't sound unreasonable - the advantages of doing so over waiting to be sued include venue selection and, perhaps more importantly, forcing the claimant to make their case, rather than letting it turn into a frozen conflict (with the possibility of them filing DMCA notices against app stores at any time). That doesn't imply they actually wanted to go to court.
Though I did just Google it, and throwing an extortion claim on top sounds... well, like a big mess.
That's exactly what they eventually did. I wouldn't have, if I thought a copyright claim against me were truly bogus. Maybe they decided it wasn't bogus.
And indeed, with a quick browse through the Wire [0] and OWS [1] repositories I just can't find any kind of commonalities at all. Not in the structure, not in the comments, not in naming, not in the data structures, etc. Am I missing something, is there anything at all in the code itself that suggests the two codebases are related in any way at all? Or is the "GPL's OWS code" you refer to something else entirely?
[0] https://github.com/wireapp/proteus/tree/develop/src/intern
[1] https://github.com/WhisperSystems/libsignal-protocol-java/tr...