Bug: habit: better error handling required [TAG=7.01g]

[paulusm <paulusm@bigpond.com>]

Hi org-mode people,

Whilst playing with the "shaving" example from
http://orgmode.org/manual/Tracking-your-habits.html I accidentally put a
bad character in the SCHEDULED timestamp.

Instead of: "SCHEDULED: <2010-08-26 Thu .+2d/4d>"
I had:      "SCHEDULED: <2010-08-26 Thu .+2nd/4d>"

When trying to view my agenda, I was presented with a blank agenda and Emacs
very quietly reported:
    "org-habit-duration-to-days: Wrong type argument: stringp, nil"
which is not really helpful.

Removing the bad character fixes the issue, and I can duplicate the error
condition as described above.

Perhaps some better error trapping could be done?


Regards,
Paul.



Emacs  : GNU Emacs 23.2.1 (i486-pc-linux-gnu, GTK+ Version 2.20.0)
 of 2010-05-16 on raven, modified by Debian
Package: Org-mode version TAG=7.01g

current state:
==============
(setq
 org-log-done 'time
 org-export-latex-after-initial-vars-hook '(org-beamer-after-initial-vars)
 org-agenda-files '("~/emacs/GTD/birthdays.org" "~/emacs/GTD/gtd.org"
		    "~/emacs/GTD/various-org-mode-demos.org")
 org-agenda-include-diary t
 org-babel-load-languages '((python . t) (emacs-lisp . t))
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-after-todo-state-change-hook '(org-clock-out-if-current)
 org-babel-tangle-lang-exts '(("python" . "py") ("emacs-lisp" . "el"))
 org-export-blocks-postblock-hook '(org-exp-res/src-name-cleanup)
 org-export-latex-format-toc-function 'org-export-latex-format-toc-default
 org-export-preprocess-hook '(org-export-blocks-preprocess)
 org-agenda-diary-file "~/emacs/GTD/gtd.org"
 org-tab-first-hook '(org-hide-block-toggle-maybe
		      org-babel-hide-result-toggle-maybe)
 org-src-mode-hook '(org-src-mode-configure-edit-buffer)
 org-confirm-shell-link-function 'yes-or-no-p
 org-export-first-hook '(org-beamer-initialize-open-trackers)
 org-agenda-before-write-hook '(org-agenda-add-entry-text)
 org-default-notes-file "~/emacs/GTD/notes.org"
 org-directory "~/emacs/GTD/"
 org-cycle-hook '(org-cycle-hide-archived-subtrees org-cycle-hide-drawers
		  org-cycle-show-empty-lines
		  org-optimize-window-after-visibility-change)
 org-export-preprocess-before-normalizing-links-hook '(org-remove-file-link-modifiers)
 org-mode-hook '(#[nil "\300\301\302\303\304$\207"
		   [org-add-hook change-major-mode-hook org-show-block-all append
		    local]
		   5]
		 #[nil "\300\301\302\303\304$\207"
		   [org-add-hook change-major-mode-hook org-babel-show-result-all
		    append local]
		   5]
		 org-babel-result-hide-spec org-babel-hide-all-hashes)
 org-agenda-ndays 1
 org-refile-targets '(("gtd.org" :level . 1))
 org-ctrl-c-ctrl-c-hook '(org-babel-lob-execute-maybe org-babel-hash-at-point
			  org-babel-execute-src-block-maybe)
 org-confirm-elisp-link-function 'yes-or-no-p
 org-export-interblocks '((lob org-babel-exp-lob-one-liners)
			  (src org-babel-exp-inline-src-blocks))
 org-occur-hook '(org-first-headline-recenter)
 org-from-is-user-regexp "\\<Paul\\>"
 org-export-preprocess-before-selecting-backend-code-hook '(org-beamer-select-beamer-code)
 org-modules '(org-bbdb org-bibtex org-docview org-gnus org-info org-jsinfo
	       org-habit org-irc org-mew org-mhe org-protocol org-rmail org-vm
	       org-wl org-w3m)
 org-export-latex-final-hook '(org-beamer-amend-header org-beamer-fix-toc
			       org-beamer-auto-fragile-frames
			       org-beamer-place-default-actions-for-lists)
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-export-blocks '((src org-babel-exp-src-blocks nil)
		     (comment org-export-blocks-format-comment t)
		     (ditaa org-export-blocks-format-ditaa nil)
		     (dot org-export-blocks-format-dot nil))
 )