> > If the code wasn't properly licensed to begin with, then he has no legal rights > > to it. > > No actually that is incorrect. If I steal some source code from someone and modify > it. Then while I don't have any rights to the code I stole, I do have rights over the > code that I wrote (as long as that code is copyrightable, not all code is). The > original owner can't then take ownership of it, or I could sue them. AFAIK this has > been tested in court before.
This is highly dependent on what exactly you do to the code, and what exactly we're asking about it. Sure, if you write some entirely new functions or blocks of code, you could retain copyright over those. But if you're modifying code that was already there, or copying it and then using it elsewhere with modifications, then you wouldn't have copyright over that code. Certainly, you couldn't distribute the entire file, so you wouldn't have rights to a usable program.
To be extremely precise, here is what I'm saying you can't do: 1) Take code that was released under license A. 2) Make substantial modifications to the code, but not to the extent that it has been entirely rewritten. 3) Release the modified code under an incompatible license B, without permission from the original author. 4) Claim shared copyright over the entire code.
If I'm understanding his arguments correctly, this is why Haze didn't want to list his name as a copyright holder at the top of files he worked on.