Derrick Stolee <stolee@xxxxxxxxx> writes: > On 12/10/2019 3:10 PM, Junio C Hamano wrote: >> KOLANICH <kolan_n@xxxxxxx> writes: [...] >>> ... the license of git itself is GPL, so I am not >>> allowed to use these 2 files to create an own permissive-licensed >>> tool reading this file. >> >> It is a wrong conclusion, isn't it? >> >> GPL copyright protects the expression of the document, but the >> copyright protects only the expression, and does not protect the >> underlying format itself and the idea behind it. So I do not see a >> need to relicense the documentation text at all. > > (Insert "I am not a lawyer" warning.) > > I think this is the correct interpretation. One can interact with > binary files as you want. In fact, there are likely privately > licensed products that interact with Git's pack-files even though > their format documentation is under GPL. > > What _could_ be problematic is repeating the documentation directly > in another permissive-licensed repository. Sidenote: I wonder if JGit, which is permissively-licensed (EDL, i.e. new-style BSD) pure-Java implementation of Git, makes use of commit graph. I remember that pack bitmaps came to Git from JGit, where that feature was first implemented. Best, -- Jakub Narębski
