# File lib/capistrano/recipes/deploy/scm/git.rb, line 211
        def query_revision(revision)
          return revision if revision =~ /^[0-9a-f]{40}$/
          command = scm('ls-remote', repository, revision)
          result = yield(command)
          revdata = result.split("\t")
          newrev = revdata[0]
          raise "Unable to resolve revision for #{revision}" unless newrev =~ /^[0-9a-f]{40}$/
          return newrev
        end