[O] Bug: markdown export errors on headers [9.0.9 (9.0.9-82-gb862c2-elpaplus @ /home/fommil/.emacs.d/elpa/org-plus-contrib-20170814/)]

[Sam Halliday]

Regression in org-plus-contrib from http://orgmode.org/elpa/ vs version
distributed with Emacs 25.2.1

Running

  M-x md-org-export-to-markdown

on a simple org file such as the following

==================================================
#+TITLE: Functional Programming in Scala for Mortals

/Functional Programming in Scala for Mortals/ is a book aimed at Scala
developers with an Object Oriented background who wish to learn the
*Functional Programming* paradigm.
==================================================

Causes the following backtrace:

Debugger entered--Lisp error: (wrong-type-argument listp #("Functional 
Programming in Scala for Mortals" 0 43 (:parent (#1))))
  org-element-set-contents(#("Functional Programming in Scala for Mortals" 0 43 
(:parent (#0))))
  apply(org-element-set-contents #("Functional Programming in Scala for 
Mortals" 0 43 (:parent (#0))) nil)
  #[257 
"\211\305\306\307#\310\311\211:\204\312\202\"address@hidden"\n)\"\210\313\314
        \211:address@hidden@address@hidden)#\210\315\211      
\n;address@hidden"*\211;address@hidden        address@hidden  address@hidden" 
[new old element property value replace-regexp-in-string "\n" " " mapc #[(blob) 
"\305  \211;\203\306\f\307\n$\202 address@hidden" [blob old value property 
element :parent org-add-props nil plist-put] 6] nil apply 
org-element-set-contents :parent get-text-property 0 plist-get org-add-props 
plist-put] 7 "\n\n(fn S)"](#("Functional Programming in Scala for Mortals" 0 43 
(:parent (#0))))
  #[257 
"\211\211:\204\211;address@hidden@\262
?\206\251\301\203-
\312\301\313\">\206\251\211\2049\314\310\242\"\202\251\211\315=\203]\314\310\242\211:address@hidden"\202\251\211\304>\203~\300!\211\203}\302\203v\317\320\"\210\202}\307\307\242B\240\210\210\306\321=\203\271
;address@hidden;address@hidden"address@hidden@A\211;address@hidden"address@hidden@address@hidden"\210\202G\310\242!\210\266
A\266\202\202\315\210\211\305>\206\251
\211:address@hidden>?\206\251\306\330=\203\216\324!\331=\206\251\314\310\242\211:address@hidden"\207"
 [#[257 
"\211\305\306\307#\310\311\211:\204\312\202\"address@hidden"\n)\"\210\313\314
      \211:address@hidden@address@hidden)#\210\315\211      
\n;address@hidden"*\211;address@hidden        address@hidden  address@hidden" 
[new old element property value replace-regexp-in-string "\n" " " mapc #[(blob) 
"\305  \211;\203\306\f\307\n$\202 address@hidden" [blob old value property 
element :parent org-add-props nil plist-put] 6] nil apply 
org-element-set-contents :parent get-text-property 0 plist-get org-add-props 
plist-put] 7 "\n\n(fn S)"] nil nil nil (plain-text) nil objects (nil) (#0) 
plain-text plist-get :ignore-list mapc org-data nil throw :--map-first-match 
objects get-text-property 0 org-element-class element reverse greater-elements 
elements object org-element-secondary-value-alist 
org-element--parsed-properties-alist org-element-dual-keywords 
org-element-multiple-keywords org-element-greater-elements] 11 "\n\n(fn 
--DATA)"](#("Functional Programming in Scala for Mortals" 0 43 (:parent (#0))))
  mapc(#[257 
"\211\211:\204\211;address@hidden@\262
?\206\251\301\203-
\312\301\313\">\206\251\211\2049\314\310\242\"\202\251\211\315=\203]\314\310\242\211:address@hidden"\202\251\211\304>\203~\300!\211\203}\302\203v\317\320\"\210\202}\307\307\242B\240\210\210\306\321=\203\271
;address@hidden;address@hidden"address@hidden@A\211;address@hidden"address@hidden@address@hidden"\210\202G\310\242!\210\266
A\266\202\202\315\210\211\305>\206\251
\211:address@hidden>?\206\251\306\330=\203\216\324!\331=\206\251\314\310\242\211:address@hidden"\207"
 [#[257 
"\211\305\306\307#\310\311\211:\204\312\202\"address@hidden"\n)\"\210\313\314
 \211:address@hidden@address@hidden)#\210\315\211      
\n;address@hidden"*\211;address@hidden        address@hidden  address@hidden" 
[new old element property value replace-regexp-in-string "\n" " " mapc #[(blob) 
"\305  \211;\203\306\f\307\n$\202 address@hidden" [blob old value property 
element :parent org-add-props nil plist-put] 6] nil apply 
org-element-set-contents :parent get-text-property 0 plist-get org-add-props 
plist-put] 7 "\n\n(fn S)"] nil nil nil (plain-text) nil objects (nil) (#0) 
plain-text plist-get :ignore-list mapc org-data nil throw :--map-first-match 
objects get-text-property 0 org-element-class element reverse greater-elements 
elements object org-element-secondary-value-alist 
org-element--parsed-properties-alist org-element-dual-keywords 
org-element-multiple-keywords org-element-greater-elements] 11 "\n\n(fn 
--DATA)"] (#("Functional Programming in Scala for Mortals" 0 43 (:parent #0))))
  #[257 
"\211\211:\204\211;address@hidden@\262
?\206\251\301\203-
\312\301\313\">\206\251\211\2049\314\310\242\"\202\251\211\315=\203]\314\310\242\211:address@hidden"\202\251\211\304>\203~\300!\211\203}\302\203v\317\320\"\210\202}\307\307\242B\240\210\210\306\321=\203\271
;address@hidden;address@hidden"address@hidden@A\211;address@hidden"address@hidden@address@hidden"\210\202G\310\242!\210\266
A\266\202\202\315\210\211\305>\206\251
\211:address@hidden>?\206\251\306\330=\203\216\324!\331=\206\251\314\310\242\211:address@hidden"\207"
 [#[257 
"\211\305\306\307#\310\311\211:\204\312\202\"address@hidden"\n)\"\210\313\314
      \211:address@hidden@address@hidden)#\210\315\211      
\n;address@hidden"*\211;address@hidden        address@hidden  address@hidden" 
[new old element property value replace-regexp-in-string "\n" " " mapc #[(blob) 
"\305  \211;\203\306\f\307\n$\202 address@hidden" [blob old value property 
element :parent org-add-props nil plist-put] 6] nil apply 
org-element-set-contents :parent get-text-property 0 plist-get org-add-props 
plist-put] 7 "\n\n(fn S)"] nil nil nil (plain-text) nil objects (nil) (#0) 
plain-text plist-get :ignore-list mapc org-data nil throw :--map-first-match 
objects get-text-property 0 org-element-class element reverse greater-elements 
elements object org-element-secondary-value-alist 
org-element--parsed-properties-alist org-element-dual-keywords 
org-element-multiple-keywords org-element-greater-elements] 11 "\n\n(fn 
--DATA)"]((#("Functional Programming in Scala for Mortals" 0 43 (:parent #0))))
  org-element-map((#("Functional Programming in Scala for Mortals" 0 43 
(:parent #0))) plain-text #[257 
"\211\305\306\307#\310\311\211:\204\312\202\"address@hidden"\n)\"\210\313\314
        \211:address@hidden@address@hidden)#\210\315\211      
\n;address@hidden"*\211;address@hidden        address@hidden  address@hidden" 
[new old element property value replace-regexp-in-string "\n" " " mapc #[(blob) 
"\305  \211;\203\306\f\307\n$\202 address@hidden" [blob old value property 
element :parent org-add-props nil plist-put] 6] nil apply 
org-element-set-contents :parent get-text-property 0 plist-get org-add-props 
plist-put] 7 "\n\n(fn S)"])
  org-export--get-inbuffer-options([cl-struct-org-export-backend md html ((bold 
. org-md-bold) (code . org-md-verbatim) (example-block . org-md-example-block) 
(export-block . org-md-export-block) (fixed-width . org-md-example-block) 
(headline . org-md-headline) (horizontal-rule . org-md-horizontal-rule) 
(inline-src-block . org-md-verbatim) (inner-template . org-md-inner-template) 
(italic . org-md-italic) (item . org-md-item) (keyword . org-md-keyword) 
(line-break . org-md-line-break) (link . org-md-link) (node-property . 
org-md-node-property) (paragraph . org-md-paragraph) (plain-list . 
org-md-plain-list) (plain-text . org-md-plain-text) (property-drawer . 
org-md-property-drawer) (quote-block . org-md-quote-block) (section . 
org-md-section) (src-block . org-md-example-block) (template . org-md-template) 
(verbatim . org-md-verbatim)) ((:md-footnote-format nil nil 
org-md-footnote-format) (:md-footnotes-section nil nil 
org-md-footnotes-section) (:md-headline-style nil nil org-md-headline-style)) 
((:filter-parse-tree . org-md-separate-elements)) nil (109 "Export to Markdown" 
((77 "To temporary buffer" (lambda (a s v b) (org-md-export-as-markdown a s 
v))) (109 "To file" (lambda (a s v b) (org-md-export-to-markdown a s v))) (111 
"To file and open" (lambda (a s v b) (if a (org-md-export-to-markdown t s v) 
(org-open-file (org-md-export-to-markdown nil s v)))))))])
  org-export-get-environment([cl-struct-org-export-backend md html ((bold . 
org-md-bold) (code . org-md-verbatim) (example-block . org-md-example-block) 
(export-block . org-md-export-block) (fixed-width . org-md-example-block) 
(headline . org-md-headline) (horizontal-rule . org-md-horizontal-rule) 
(inline-src-block . org-md-verbatim) (inner-template . org-md-inner-template) 
(italic . org-md-italic) (item . org-md-item) (keyword . org-md-keyword) 
(line-break . org-md-line-break) (link . org-md-link) (node-property . 
org-md-node-property) (paragraph . org-md-paragraph) (plain-list . 
org-md-plain-list) (plain-text . org-md-plain-text) (property-drawer . 
org-md-property-drawer) (quote-block . org-md-quote-block) (section . 
org-md-section) (src-block . org-md-example-block) (template . org-md-template) 
(verbatim . org-md-verbatim)) ((:md-footnote-format nil nil 
org-md-footnote-format) (:md-footnotes-section nil nil 
org-md-footnotes-section) (:md-headline-style nil nil org-md-headline-style)) 
((:filter-parse-tree . org-md-separate-elements)) nil (109 "Export to Markdown" 
((77 "To temporary buffer" (lambda (a s v b) (org-md-export-as-markdown a s 
v))) (109 "To file" (lambda (a s v b) (org-md-export-to-markdown a s v))) (111 
"To file and open" (lambda (a s v b) (if a (org-md-export-to-markdown t s v) 
(org-open-file (org-md-export-to-markdown nil s v)))))))] nil (:output-file 
"./README.md"))
  org-export-as(md nil nil nil (:output-file "./README.md"))
  org-export-to-file(md "./README.md" nil nil nil)
  org-md-export-to-markdown()
  funcall-interactively(org-md-export-to-markdown)
  call-interactively(org-md-export-to-markdown record nil)
  command-execute(org-md-export-to-markdown record)
  execute-extended-command(nil "org-md-export-to-markdown" nil)
  funcall-interactively(execute-extended-command nil 
"org-md-export-to-markdown" nil)
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)

------------------------------------------------------------------------



Emacs  : GNU Emacs 25.2.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.22.16)
 of 2017-07-16
Package: Org mode version 9.0.9 (9.0.9-82-gb862c2-elpaplus @ 
/home/fommil/.emacs.d/elpa/org-plus-contrib-20170814/)

current state:
==============
(setq
 org-tab-first-hook '(org-babel-hide-result-toggle-maybe
                      org-babel-header-arg-expand)
 org-speed-command-hook '(org-speed-command-default-hook
                          org-babel-speed-command-hook)
 org-occur-hook '(org-first-headline-recenter)
 org-metaup-hook '(org-babel-load-in-session-maybe)
 org-html-format-drawer-function #[514 "\207" [] 3 "\n\n(fn NAME CONTENTS)"]
 org-latex-format-inlinetask-function 
'org-latex-format-inlinetask-default-function
 org-confirm-shell-link-function 'yes-or-no-p
 org-ascii-format-inlinetask-function 'org-ascii-format-inlinetask-default
 org-latex-format-headline-function 'org-latex-format-headline-default-function
 org-after-todo-state-change-hook '(org-clock-out-if-current)
 org-latex-format-drawer-function #[514 "\207" [] 3 "\n\n(fn _ CONTENTS)"]
 org-odt-format-headline-function 'org-odt-format-headline-default-function
 org-src-mode-hook '(org-src-babel-configure-edit-buffer
                     org-src-mode-configure-edit-buffer)
 org-agenda-before-write-hook '(org-agenda-add-entry-text)
 org-babel-pre-tangle-hook '(save-buffer)
 org-mode-hook '(#[0 "\300\301\302\303\304$\207"
                   [add-hook change-major-mode-hook org-show-block-all append 
local]
                   5]
                 #[0 "\300\301\302\303\304$\207"
                   [add-hook change-major-mode-hook org-babel-show-result-all
                    append local]
                   5]
                 org-babel-result-hide-spec org-babel-hide-all-hashes
                 writing-mode-hooks
                 (closure (t) nil (yas-minor-mode t) (company-mode t)
                  (visual-line-mode t)
                  (local-set-key (kbd "s-c") (quote picture-mode))
                  (org-babel-do-load-languages (quote org-babel-load-languages)
                   (quote ((ditaa . t) (dot . t))))
                  )
                 org-eldoc-load)
 org-archive-hook '(org-attach-archive-delete-maybe)
 org-ascii-format-drawer-function #[771 "\207" [] 4 "\n\n(fn NAME CONTENTS 
WIDTH)"]
 org-odt-format-inlinetask-function 'org-odt-format-inlinetask-default-function
 org-cycle-hook '(org-cycle-hide-archived-subtrees org-cycle-hide-drawers
                  org-cycle-show-empty-lines
                  org-optimize-window-after-visibility-change)
 org-confirm-elisp-link-function 'yes-or-no-p
 org-metadown-hook '(org-babel-pop-to-session-maybe)
 org-odt-format-drawer-function #[514 "\207" [] 3 "\n\n(fn NAME CONTENTS)"]
 org-ditaa-jar-path "/home/fommil/.ditaa.jar"
 org-html-format-headline-function 'org-html-format-headline-default-function
 org-link-parameters '(("id" :follow org-id-open)
                       ("rmail" :follow org-rmail-open :store 
org-rmail-store-link)
                       ("mhe" :follow org-mhe-open :store org-mhe-store-link)
                       ("irc" :follow org-irc-visit :store org-irc-store-link)
                       ("info" :follow org-info-open :export org-info-export 
:store
                        org-info-store-link)
                       ("gnus" :follow org-gnus-open :store org-gnus-store-link)
                       ("docview" :follow org-docview-open :export
                        org-docview-export :store org-docview-store-link)
                       ("bibtex" :follow org-bibtex-open :store
                        org-bibtex-store-link)
                       ("bbdb" :follow org-bbdb-open :export org-bbdb-export
                        :complete org-bbdb-complete-link :store 
org-bbdb-store-link)
                       ("w3m" :store org-w3m-store-link) ("file+sys")
                       ("file+emacs") ("doi" :follow org--open-doi-link)
                       ("elisp" :follow org--open-elisp-link)
                       ("file" :complete org-file-complete-link)
                       ("ftp" :follow
                        (lambda (path) (browse-url (concat "ftp:" path))))
                       ("help" :follow org--open-help-link)
                       ("http" :follow
                        (lambda (path) (browse-url (concat "http:" path))))
                       ("https" :follow
                        (lambda (path) (browse-url (concat "https:" path))))
                       ("mailto" :follow
                        (lambda (path) (browse-url (concat "mailto:"; path))))
                       ("message" :follow
                        (lambda (path) (browse-url (concat "message:" path))))
                       ("news" :follow
                        (lambda (path) (browse-url (concat "news:"; path))))
                       ("shell" :follow org--open-shell-link))
 org-babel-load-languages '((ditaa . t) (dot . t))
 org-html-format-inlinetask-function 
'org-html-format-inlinetask-default-function
 org-clock-out-hook '(org-clock-remove-empty-clock-drawer)
 org-confirm-babel-evaluate nil
 org-export-headline-levels 5
 )
-- 
Best regards,
Sam