(monky-status) errors out without message in cmdserver

[yubinbai]

(monky-status) output

Debugger entered--Lisp error: (error "")
signal(error (""))
error("")
monky-hg-output(("root"))
monky-hg-string("root")
monky-get-local-root-dir()
monky-get-root-dir()
monky-status()
eval((monky-status) nil)
elisp--eval-last-sexp(nil)
eval-last-sexp(nil)
funcall-interactively(eval-last-sexp nil)
call-interactively(eval-last-sexp nil nil)
command-execute(eval-last-sexp)