Set separate remote for pushing and pulling only subfolder

Question

Let's say I have two repos, repo A and repo B, which contains a folder with code similar to the code in repo A (doesn't really matter how this actually has happened, but OK, let's assume I've just copied contents from A).

Now I want following:

• To work just as I got used to in repo A
• To set and additional remote repo pointing to repo B, but pushing and pulling only this subfolder.
• To push, when it needed to this repo B.

So, basically, I'm looking for the cheapest way to have something like reversed sparsed check out.

Answer 1

It seems exactly the kind of problem git-subtree1 tries to solve.

cd repoB
git subtree pull -P folder {repoA URL} {repoA branch}
... edit test commit... 
git subtree push -P folder {repoA URL} {repoA branch}

Answer 2

You can add a ref for and so publish anything in a repo. So, to maintain a separate branch that tracks the main branch's subfolder, add this to your commit ritual:

# in your commit ritual (no need to be mainbranch-specific, 
# this will detect changes and add the tracking commits only as necessary),
if [ `git rev-parse mainbranch:path/to/subfolder` \
      != `git rev-parse subfolderbranch:path/to/subfolder` ]; then 
    git commit-tree -p subfolderbranch -p mainbranch \
              mainbranch:path/to/subfolder <<<"tracking mainbranch subfolder" \
    | xargs git update-ref -m"tracking mainbranch subfolder" refs/heads/subfolderbranch 
fi