add all files in given dir to the index.

create a new branch and check it out.

commit the index with the given message.

perform init and fetch in one step but only init if the repo doesn't exist.

fetch the given refs from origin with depth 1.

initialite the git repo at dir and set the remote origin to uri.

perform add, commit, and push in one step, on the current branch.

push the given refs to origin.

switch to ref.

the package uri is a special uri format to specify a git repo, ref, and package path within the repo under the ref.

the repo cache will keep a clean version of each repo fetched via Fill().