How do you set up a git repository where some users can see certain parts of the source code and other users can see all of it? I've seen lots of guides for only giving certain users commit access, but these assume everyone should have read access. I've also heard of gitosis, but I'm not sure it supports this and it hasn't had any commits in over a year so I think it's dead.
In short: you can't. Git is snapshot based (at conceptual level at least) version control system, not changeset based one. It treats project (repository) as a whole. The history is a history of a project, not a union of single-file histories (it is more than joining of per-file histories).
Using hooks like update-paranoid hook in contrib, or VREFs mechanism of gitolite, you can allow or forbid access to repository, you can allow or forbid access to individual branches. You can even forbid any commits that change things in specified subdirectory. But the project is always treated as a whole.
Well, there is one thing you can do: make a directory you want to restrict access to into submodule, and restrict access to this submodule repository.
The native git protocol doesn't support this; git assumes in many places that everybody has a complete copy of all of the history.
That said, one option may be to use git-subtree to split off part of the repository into its own subset repository, and periodically merge back.
Git doesn't support access control on the repository. You can however, implement access control on the repository yourself, by using hooks, more specifically the update hook.
Jörg has already pointed out that you can use hooks to do this. Exactly which hook(s) you need depends on your setup. If you want the permissions on a repo that gets pushed to, you'll need the update hook like he said. However, if it's on a repo that you're actually working in (committing and merging), you'll also need the pre-commit and post-merge hooks. The githooks manpage (Jörg linked to this too) notes that there's in fact a script in the contrib section demonstrating a way to do this. You can get this by grabbing a git tarball, or pull it out of git's gitweb repo: setgitperms.perl. Even if you're only using the update hook, that might be a useful model.
来源：https://stackoverflow.com/questions/1196312/how-to-set-up-a-git-repository-where-different-users-can-only-see-certain-parts