The length of the commit hash returned for `--short` can vary depending
on user configuration. Make sure this works independently of what might
have been configured via a user's `.gitconfig`. This also fixes the
failing `GitDownloadStrategyTests#test_last_commit` test for such users.
This is the (partially) documented public API for Homebrew.
The main class you should look at is the {Formula} class (and classes linked from there). That's the class that's used to create Homebrew formulae (i.e. package descriptions). Assume anything else you stumble upon is private.