fixup! Arcyd: use new branch abstraction to simplify
fixup! Arcyd: use new branch abstraction to simplify
fixup! Arcyd: use new branch abstraction to simplify
fixup! Arcyd: use new branch abstraction to simplify
fixup! Arcyd: use new branch abstraction to simplify
fixup! Arcyd: use new branch abstraction to simplify
fixup! Arcyd: use new branch abstraction to simplify
Arcyd: sanitize git abstraction

To make it easier to mock and test the git abstraction, sanitize it's
usage by client code.

Test Plan: $ ./precommit.sh
fixup! Arcyd: sanitize git abstraction