> Unfortunately, now Dired fails to visit a directory:
 >
 > Debugger entered--Lisp error: (wrong-type-argument stringp nil)
 >    file-name-absolute-p(nil)
 >    dired-goto-file(nil)
 >    dired-restore-positions(((#<buffer /tmp/> nil 3) nil ((#<marker at 1 in /tmp/> nil 3))))
 >    dired-revert(nil nil)
 >    revert-buffer()
 >    dired-internal-noselect("/tmp/" nil)
 >    dired-noselect("/tmp/" nil)
 >    dired("/tmp/")
 >    dired-jump(nil nil)
 >    funcall-interactively(dired-jump nil nil)
 >    call-interactively(dired-jump nil nil)
 >    command-execute(dired-jump)
 >
 > Maybe this happens when a reverted directory window is restored
 > from a window configuration, so point-marker is at 1,
 > and (dired-get-filename nil t) returns nil in `dired-save-positions'.

Looks like a silly typo.  Please try the attached patch.  If it does
not help, please provide me a simple scenario to reproduce the bug.

Thanks, martin