Can I associate ssh username with commit with git over ssh?

Question

I am trying to setup a shared git repository via ssh, copying users public keys to the authorized_keys. I'd really like the "username" from the ssh-key to be part of the commit history in the repo (so that the user "joe" cannot just set his name to be "kate" - we need some kind of accountability). Is there any way to do this ?

Answer 1

Simply, no, there is no way. The reason is that the author and committer details are set when a commit is made and this usually happens locally. A git push happens at a later time to push existing commits to the remote repository. Because the commits are already made and referenced by SHA1 hash, they cannot be altered during a push operation.

What you might consider doing is having a pre-receive or update hook that prevents people from pushing commits that they haven't authored, but this might prevent a lot of legitimate uses. You may find that trusting your users is the only sensible option.

Answer 2

That won't work with the decentralized nature of git. Imagine joe merges kate's development branch. There are commits from joe and kate in his local clone now:

*  joe: Merge branch 'kate'
|\  
| * joe: update foo
* | kate: fix test
* | kate: add test
|/  
* joe: initial commit

If joe pushes to the central repository now, and you are enforcing the username, kate's commits would be attributed to joe.