paulusm <paulusm@bigpond.com> writes:

> 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?
>
>

Attached is the patch which catch this error and throws meaningful
message.

lisp/org-habit.el : (org-habit-parse-todo)
  - Find sr-days only if scheduled-repeat is non nil
  - Used 4th element of the list returned by (org-heading-components)
    as habit-entry
  - Modified the error message to be more meaningful.

Thanks and Regards
Noorul