boxen/puppet-homebrew — pull request #44 by dgoodlad (2014-04-15 10:26:01+00:00)
Title: Handle minimum revisions which we haven't fetched

`git rev-list` returns a non-zero exit status if its asked about a ref that it can't find (logically). We need to handle this case, since the minimum revision specified may not have been fetched from the remote yet.