the heimlich: dirty hack to unchoke gist-region on `%'

gist.el

(defadvice gist-region (around su/advice/gist/gist-region/around/dirty-hack
                               a c pre)
  "Dirty hack to prevent gist-region from choking on buffers which contain
     `%' character"
  (save-window-excursion
    (let* ((delete-old-versions t)
           (dummy "foo")
           (beg (ad-get-arg 0))
           (end (ad-get-arg 1))
           (min-beg-end (min beg end))
           (original-text (buffer-substring beg end))
           gistid buf proc)
      (kill-region beg end)
      (insert-for-yank-1 dummy)
      (ad-set-arg 0 min-beg-end)
      (ad-set-arg 1 (point))
      ad-do-it
      (sleep-for 0.5) ;; deep magic
      (dolist (buf (buffer-list))
        (when (string-match "^\\s-\\*http api\\.github\\.com:443\\*$" (buffer-name
                                                                       buf))
          (setq proc (get-buffer-process buf))
          (when proc (kill-process proc))
          ))
      (delete-region min-beg-end (point))
      (insert-for-yank-1 original-text)
      (setq gistid (car (last (split-string (car kill-ring)
                                            "/"))))
      (setq buf (gist-fetch gistid))
      (with-current-buffer buf
        (delete-region (point-min)
                       (point-max))
        (insert-for-yank-1 original-text)
        (gist-mode-save-buffer)
        (kill-buffer))

      )))

That fixed it for me thank you