[PATCH] Fix inconsistency in drawer handling

[Yann Hodique <yann.hodique@gmail.com>]

* lisp/org.el (org-drawer-end-re): Introduce new constant.
(org-clock-drawer-start-re): Fix docstring.
(org-clock-drawer-end-re): Fix docstring.
(org-flag-drawer): Make use of `org-drawer-end-re'.
(org-end-of-meta-data-and-drawers): Make use of `org-drawer-end-re'.

* lisp/org-element.el (org-element-drawer-parser): Make use of
  `org-drawer-end-re'.
(org-element-property-drawer-parser): Make use of `org-drawer-end-re'.

Subtle differences in the definition of drawers delimiters were leading
to inconsistencies. For example, the following drawer:

  :PROPERTIES:
  :start: now
  :end:   then
  :END:

was interpreted by `org-entry-properties' as containing properties
"start" and "end", whereas the cycling code would hide at the
first :end:, and `org-element-drawer-parser' would also consider the
black to end at the first :end:.
---
 lisp/org-element.el |  8 ++++----
 lisp/org.el         | 18 ++++++++++++------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/lisp/org-element.el b/lisp/org-element.el
index bcdd336..9822045 100644
--- a/lisp/org-element.el
+++ b/lisp/org-element.el
@@ -529,7 +529,7 @@ Return a list whose CAR is `drawer' and CDR is a plist containing
 
 Assume point is at beginning of drawer."
   (let ((case-fold-search t))
-    (if (not (save-excursion (re-search-forward "^[ \t]*:END:" limit t)))
+    (if (not (save-excursion (re-search-forward org-drawer-end-re limit t)))
 	;; Incomplete drawer: parse it as a paragraph.
 	(org-element-paragraph-parser limit)
       (let ((drawer-end-line (match-beginning 0)))
@@ -1895,7 +1895,7 @@ Assume point is at the beginning of the property drawer."
 	  (hidden (org-invisible-p2))
 	  (properties
 	   (let (val)
-	     (while (not (looking-at "^[ \t]*:END:"))
+	     (while (not (looking-at org-property-end-re))
 	       (when (looking-at "[ \t]*:\\([A-Za-z][-_A-Za-z0-9]*\\):")
 		 (push (cons (org-match-string-no-properties 1)
 			     (org-trim
@@ -1904,7 +1904,7 @@ Assume point is at the beginning of the property drawer."
 		       val))
 	       (forward-line))
 	     val))
-	  (prop-end (progn (re-search-forward "^[ \t]*:END:" limit t)
+	  (prop-end (progn (re-search-forward org-property-end-re limit t)
 			   (point-at-bol)))
 	  (pos-before-blank (progn (forward-line) (point)))
 	  (end (progn (skip-chars-forward " \r\t\n" limit)
@@ -3395,7 +3395,7 @@ element it has to parse."
         (let ((name (match-string 1)))
 	  (cond
 	   ((not (save-excursion
-		   (re-search-forward "^[ \t]*:END:[ \t]*$" nil t)))
+		   (re-search-forward org-drawer-end-re nil t)))
 	    (org-element-paragraph-parser limit))
 	   ((equal "PROPERTIES" name)
 	    (org-element-property-drawer-parser limit))
diff --git a/lisp/org.el b/lisp/org.el
index 1c18d70..f62bde6 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -6768,6 +6768,9 @@ open and agenda-wise Org files."
 	(while (re-search-forward org-drawer-regexp end t)
 	  (org-flag-drawer t))))))
 
+(eval-when-compile
+  (defvar org-drawer-end-re))
+
 (defun org-flag-drawer (flag)
   "When FLAG is non-nil, hide the drawer we are within.
 Otherwise make it visible."
@@ -6776,7 +6779,7 @@ Otherwise make it visible."
     (when (looking-at "^[ \t]*:[a-zA-Z][a-zA-Z0-9]*:")
       (let ((b (match-end 0)))
 	(if (re-search-forward
-	     "^[ \t]*:END:"
+	     org-drawer-end-re
 	     (save-excursion (outline-next-heading) (point)) t)
 	    (outline-flag-region b (point-at-eol) flag)
 	  (error ":END: line missing at position %s" b))))))
@@ -14308,17 +14311,20 @@ but in some other way.")
   "Some properties that are used by Org-mode for various purposes.
 Being in this list makes sure that they are offered for completion.")
 
+(defconst org-drawer-end-re "^[ \t]*:END:[ \t]*$"
+  "Regular expression matching the last line of a drawer.")
+
 (defconst org-property-start-re "^[ \t]*:PROPERTIES:[ \t]*$"
   "Regular expression matching the first line of a property drawer.")
 
-(defconst org-property-end-re "^[ \t]*:END:[ \t]*$"
+(defconst org-property-end-re org-drawer-end-re
   "Regular expression matching the last line of a property drawer.")
 
 (defconst org-clock-drawer-start-re "^[ \t]*:CLOCK:[ \t]*$"
-  "Regular expression matching the first line of a property drawer.")
+  "Regular expression matching the first line of a clock drawer.")
 
-(defconst org-clock-drawer-end-re "^[ \t]*:END:[ \t]*$"
-  "Regular expression matching the first line of a property drawer.")
+(defconst org-clock-drawer-end-re org-drawer-end-re
+  "Regular expression matching the first line of a clock drawer.")
 
 (defconst org-property-drawer-re
   (concat "\\(" org-property-start-re "\\)[^\000]*\\("
@@ -22080,7 +22086,7 @@ clocking lines, and drawers."
 	  ;; empty or planning line
 	  (forward-line 1)
 	;; a drawer, find the end
-	(re-search-forward "^[ \t]*:END:" end 'move)
+	(re-search-forward org-drawer-end-re end 'move)
 	(forward-line 1)))
     (and (re-search-forward "[^\n]" nil t) (backward-char 1))
     (point)))
-- 
1.7.12