Emacs org-mode Python source blocks don't export with python-mode.el

Question

I recently configured my Emacs setup to use python-mode.el instead of python.el. This changed has apparently caused org mode to no longer be able to export python source blocks, as I get

org-export-format-source-code-or-example: "End of buffer"

as the only message after export, and no export file is generated.

I'd like to know why this is, and what I can do to fix it. My python-mode.el is installed through el-get (not that I think that is important). It is loaded in my init file like so:

(add-to-list 'load-path "~/.emacs.d/el-get/python-mode/")
(autoload 'python-mode "python-mode" "Python Mode." t)
(add-to-list 'auto-mode-alist '("\\.py\\'" . python-mode))
(add-to-list 'interpreter-mode-alist '("python" . python-mode))

Here's the sample that produces this error:

This is a test.

#+BEGIN_SRC python
  print "Hello, World"
#+END_SRC

And here is what I see in Messages :

Export buffer: 
Exporting...
org-babel-exp processing...
org-export-format-source-code-or-example: End of buffer

Answer 1

In my configuration,

• GNU Emacs 24.3.1,
• python-mode 6.1.3,
• org 20141006

I have the same problem. When I trace what causes this error, I found that org-html-fontifiy-code in ox-html.el causes this error. Especially code block around below:

(save-excursion
  (let ((beg (point-min))
        (end (point-max)))
    (goto-char beg)
    (while (progn (end-of-line) (< (point) end))
       (put-text-property (point) (1+ (point)) 'face nil)
       (forward-char 1))))

Normally, in the last iteration of the while loop, the point before put-text-property usually has the value (1- (point-max)) , putting text property (which does not change the point ), then it calls forward-char to move the point to (point-max) , and stop the while loop.

Strangely, in python source block, put-text-property moves the point to (1+ (point)) . So in the last iteration, put-text-property moves the point to (1+ (point)) , so that the point is already at the (point-max) , so calling forward-char will fail with "End of buffer" error.

I smell the fish in python-mode ; Perhaps they install some hook functions or something to make put-text-property moves the point? I'm not sure. For the monkey patch, here's the dirty patch for above code block:

(save-excursion
  (let ((beg (point-min))
        (end (point-max)))
    (goto-char beg)
    (while (progn (end-of-line) (< (point) end))
      (let ((oldpos (point)))
        (put-text-property (point) (1+ (point)) 'face nil)
        (goto-char oldpos))
      (forward-char 1))))

Sorry for my laziness, but could anyone post this to org-mode/python-mode mailing list?

Answer 2

AFAIS when exporting source-code, the language-modes are not queried.

It's a matter of the exporter.