[PATCH 1/2] Fix error with %e agenda prefix format when there is no effort set

[Max Mikhanosha <max@openchat.com>]

`org-agenda-prefix-format' has un undocumented format %e for Effort, which
is broken. it throws error on entries without effort property.

Following patch fixes that problem. TODO: make agenda redraw current line
when `org-agenda-set-effort' sets a new effort

From c06b376737142eff5cdec71e8fc8129552aba673 Mon Sep 17 00:00:00 2001
From: Max Mikhanosha <max@openchat.com>
Date: Wed, 6 Jul 2011 20:05:06 -0400
Subject: [PATCH 1/2] Fix error with %e agenda prefix format when there is no effort set

---
 lisp/org-agenda.el |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/lisp/org-agenda.el b/lisp/org-agenda.el
index cd09a74..f34ffae 100644
--- a/lisp/org-agenda.el
+++ b/lisp/org-agenda.el
@@ -5511,7 +5511,9 @@ Any match of REMOVE-RE will be removed from TXT."
 		(error nil)))
 	(when effort
 	  (setq neffort (org-duration-string-to-minutes effort)
-		effort (setq effort (concat "[" effort "]" )))))
+		effort (setq effort (concat "[" effort "]")))))
+      ;; prevent erroring out with %e format when there is no effort
+      (or effort (setq effort ""))
 
       (when remove-re
 	(while (string-match remove-re txt)
@@ -5549,6 +5551,7 @@ Any match of REMOVE-RE will be removed from TXT."
 		 (>= (length category) org-prefix-category-max-length))
 	    (setq category (substring category 0 (1- org-prefix-category-max-length)))))
       ;; Evaluate the compiled format
+      (assert effort)
       (setq rtn (concat (eval org-prefix-format-compiled) txt))
 
       ;; And finally add the text properties
-- 
1.7.3.4