https://github.com/Shinmera/legit.git
git clone 'http://github.com/Shinmera/legit.git'
(ql:quickload :legit)
This is an interface to the GIT binary to make controlling it from within CL much easier. I've had the need to do this kind of thing a couple of times now, so I might as well encapsulate it into a proper library. I don't know if this is ever going to reach full coverage of all features given GIT's immense size, but I will add features as they are needed. The low-level command API is fully mapped however.
You will need the git binary in your PATH. Once you got that, and have this system loaded via ASDF or Quicklisp, you can access all the git commands through functions.
(legit:with-chdir ("some/git/dir")
(legit:git-rev-parse "HEAD" :short T))
All commands have been hand-rewritten to work through the uniform and comfortable API we're used to from Lisp. There is an even more convenient (albeit incomplete) interface using repository instances.
(let ((repository (make-instance 'legit:repository :location "some/git/dir")))
(values (legit:commits repository)
(legit:current-branch repository)
(legit:remote-url repository)))
A lot of the information about a repository that you can access will automatically be cached until some destructive operation (like a pull) occurs, so that querying that information does not take so much time each request.