M-x compile problem under tramp

[sunway <sunwayforever@gmail.com>]

I have been using this elisp code:

(setq compilation-finish-function
      (lambda (buf str)
        (if (string-match "exited abnormally" str)
            (message "compilation errors, press C-x ` to visit")
          ;;no errors, make the compilation window go away in 0.5
seconds
          (run-at-time 0.5 nil 'delete-windows-on buf)
          (message "NO COMPILATION ERRORS!"))))

to close the Compilation buffer when there is no compilation error
when compiling.

how ever, when using M-x compile under tramp, the command will always
return "..finished.." instead of "exited abnormally" when there is
compilation error.  so the Compilation buffer will always be closed.
how to fix the problem?