bug in org-element-parse-buffer, affects new HTML exporter

[Eric Schulte <eric.schulte@gmx.com>]

Hi,

Save the following text to an Org-mode file,

- one :: first
- two :: - second
- three :: third

and then call the `org-element-parse-buffer' function from within that
buffer.  The following error will result.  This breaks the new export
engine for buffers containing text like the above.

Thanks,

,----
| Debugger entered--Lisp error: (wrong-type-argument stringp nil)
|   string-match("[[:alnum:]]" nil)
|   org-list-get-list-type(25 ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)) ((1) (16 . 1) (34 . 16)))
|   org-element-plain-list-parser(34 ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)))
|   org-element--current-element(34 nil nil ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)))
|   org-element--parse-elements(25 34 nil ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)) nil nil (item (:bullet "- " :begin 16 :end 34 :contents-begin 25 :contents-end 34 :checkbox nil :counter nil :hiddenp nil :structure ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)) :post-blank 0 :tag ("two"))))
|   org-element--parse-elements(1 51 item ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)) nil nil (plain-list (:type descriptive :begin 1 :end 51 :contents-begin 1 :contents-end 51 :structure ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)) :post-blank 0) (item (:bullet "- " :begin 1 :end 16 :contents-begin 10 :contents-end 16 :checkbox nil :counter nil :hiddenp nil :structure ((1 0 "- " nil nil "one" 16) (16 0 "- " nil nil "two" 34) (34 0 "- " nil nil "three" 51)) :post-blank 0 :tag ("one") :parent #0) (paragraph (:begin 10 :end 16 :contents-begin 10 :contents-end 16 :post-blank 0 :parent #1) "first\n"))))
|   org-element--parse-elements(1 51 nil nil nil nil (section (:begin 1 :end 51 :contents-begin 1 :contents-end 51 :post-blank 0)))
|   org-element--parse-elements(1 51 first-section nil nil nil (org-data nil))
|   org-element-parse-buffer()
|   eval((org-element-parse-buffer) nil)
|   eval-expression((org-element-parse-buffer) nil)
|   call-interactively(eval-expression nil nil)
`----

-- 
Eric Schulte
http://cs.unm.edu/~eschulte