Org-src-fontify-natively makes Magit think there are unsaved files

Question

I've got a weird one for you. When all of the following are true:

• I'm using org-mode
• My org-mode file has a code block
• I export the org file
• org-src-fontify-natively is true

Then I get a leftover buffer with a name like " org-src-fontification:clojure-mode". It's considered an "invisible" buffer, so it only shows up when listing buffers from Elisp code. It does not appear in the interactive buffer list.

The next time I refresh my magit-status, I get prompted to save a file. There's no option to skip it! If I save the file, it has the contents of the leftover internal buffer.

If I turn off org-src-fontify-natively then this doesn't happen. But my exports also don't get nice fontification either.

Is there some way to either discard that buffer, or convince magit to ignore it?

Answer 1

One workaround is to advise the functions involved. For example, you could add :after advice to org-src-font-lock-fontify-block to kill the buffer it creates, perhaps like this:

(defun kill-org-src-buffers (&rest args)
  "Kill temporary buffers created by
org-src-font-lock-fontify-block so they don't interfere with
magit-mode."
  (dolist (b (buffer-list))
    (let ((bufname (buffer-name b)))
      (if (string-prefix-p " org-src-fontification:" bufname)
          (kill-buffer b)))))

(advice-add 'org-src-font-lock-fontify-block
            :after #'kill-org-src-buffers)    

The kill-org-src-buffers iterates over all buffers, killing any that match the buffer name prefix that org-src-font-lock-fontify-block uses for its "temporary" buffers. Alternatively, advising magit-save-repository-buffers with :before advice that takes a similar approach would likely work too.

I think it's a bug that org-src-font-lock-fontify-block creates a buffer using get-buffer-create to do work that appears to require only a temporary buffer; it should use with-temp-buffer instead.