Re: [PATCH v3 1/2] rev-parse: add --prefix option

John Keeping wrote:

It looks to me like setup_git_directory() returns NULL if we're at the
top of the working tree so we do need that check.  I suspect that's so
that "!prefix" does the right thing.

Ah, yes.  My bad.  I expected it to return "/" on the toplevel
directory actually.