The following git command line provides a count of the commits that origin/master is ahead of master (local copy)
git rev-list --count master..origin/master
Output will be 0 if not ahead, or n for the number of additional commits made to origin/master.
How could I get this same information using the rugged gem in a ruby-native fashion?
Rugged documentation and API docs for the underlying libgit2 are really
byzantine, and difficult to parse. It's complex stuff, I get it, but I can't find any references to the rev-list command, so I'm not sure where to look.