src/Pure/General/mercurial.scala

   def setup_repository(source: String, root: Path, ssh: Option[SSH.Session] = None): Repository =
     ssh match {
       case None => if (root.is_dir) repository(root) else clone_repository(source, root)
       case Some(session) =>
         using(session.sftp())(sftp =>
-          if (sftp.is_dir(sftp.path(root))) repository(root, ssh = ssh)
+          if (sftp.is_dir(root)) repository(root, ssh = ssh)
           else clone_repository(source, root, ssh = ssh))
     }
 
   class Repository private[Mercurial](root_path: Path, ssh: Option[SSH.Session])
   {