From ec36f46a1ac57e99e34db29cf71379d91a8d6b9b Mon Sep 17 00:00:00 2001
From: Le Wang <le.wang@agworld.com.au>
Date: Sun, 18 Nov 2012 13:39:51 +0800
Subject: [PATCH] fix org-edit-src-code for empty blocks and block with just
 an empty line

- use marker with insertion type 't to track end and remove hack requiring
  delete from `beg' to `(1- end)'
---
 lisp/org-src.el | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/lisp/org-src.el b/lisp/org-src.el
index 75db1d7..4bd85a6 100644
--- a/lisp/org-src.el
+++ b/lisp/org-src.el
@@ -215,11 +215,23 @@ buffer."
     (setq org-edit-src-saved-temp-window-config (current-window-configuration)))
   (let* ((mark (and (org-region-active-p) (mark)))
 	 (case-fold-search t)
-	 (info (org-edit-src-find-region-and-lang))
+	 (info
+	  ;; if the src region consistes of no lines, we insert a
+	  ;; blank line.
+	  (let* ((temp (org-edit-src-find-region-and-lang))
+		 (beg (nth 0 temp))
+		 (end (nth 1 temp)))
+	    (if (< end beg)
+		(progn (goto-char beg)
+		       (insert "\n")
+		       (org-edit-src-find-region-and-lang))
+	      temp)))
 	 (full-info (org-babel-get-src-block-info 'light))
 	 (org-mode-p (derived-mode-p 'org-mode)) ;; derived-mode-p is reflexive
 	 (beg (make-marker))
-	 (end (make-marker))
+	 ;; move marker with inserted text for case when src block is
+	 ;; just one empty line, i.e. beg == end
+	 (end (copy-marker nil t))
 	 (allow-write-back-p (null code))
 	 block-nindent total-nindent ovl lang lang-f single lfmt buffer msg
 	 begline markline markcol line col transmitted-variables)
@@ -689,10 +701,9 @@ with \",*\", \",#+\", \",,*\" and \",,#+\"."
       (kill-buffer buffer))
     (goto-char beg)
     (when allow-write-back-p
-      (delete-region beg (max beg (1- end)))
+      (delete-region beg (max beg end))
       (unless (string-match "\\`[ \t]*\\'" code)
-	(insert code)
-	(delete-char 1))
+	(insert code))
       (goto-char beg)
       (if single (just-one-space)))
     (if (memq t (mapcar (lambda (overlay)
-- 
1.7.11.4
