Fix exporting visible parts of a buffer

* lisp/org-element.el (org-element--parse-elements): Only ignore parts
due to folding, not because of fontification.
* lisp/org-macs.el (org-invisible-p): Add an optional argument.
* testing/lisp/test-org-element.el (test-org-element/parse-buffer-visible):
Add tests.

lisp/org-element.el

@@ -4361,54 +4361,52 @@ elements.
 Elements are accumulated into ACC."
   (save-excursion
     (goto-char beg)
-    ;; Visible only: skip invisible parts at the beginning of the
-    ;; element.
-    (when (and visible-only (org-invisible-p2))
-      (goto-char (min (1+ (org-find-visible)) end)))
     ;; When parsing only headlines, skip any text before first one.
     (when (and (eq granularity 'headline) (not (org-at-heading-p)))
       (org-with-limited-levels (outline-next-heading)))
     (let (elements)
       (while (< (point) end)
-	;; Find current element's type and parse it accordingly to
-	;; its category.
-	(let* ((element (org-element--current-element
-			 end granularity mode structure))
-	       (type (org-element-type element))
-	       (cbeg (org-element-property :contents-begin element)))
-	  (goto-char (org-element-property :end element))
-	  ;; Visible only: skip invisible parts between siblings.
-	  (when (and visible-only (org-invisible-p2))
-	    (goto-char (min (1+ (org-find-visible)) end)))
-	  ;; Fill ELEMENT contents by side-effect.
-	  (cond
-	   ;; If element has no contents, don't modify it.
-	   ((not cbeg))
-	   ;; Greater element: parse it between `contents-begin' and
-	   ;; `contents-end'.  Make sure GRANULARITY allows the
-	   ;; recursion, or ELEMENT is a headline, in which case going
-	   ;; inside is mandatory, in order to get sub-level headings.
-	   ((and (memq type org-element-greater-elements)
-		 (or (memq granularity '(element object nil))
-		     (and (eq granularity 'greater-element)
-			  (eq type 'section))
-		     (eq type 'headline)))
-	    (org-element--parse-elements
-	     cbeg (org-element-property :contents-end element)
-	     ;; Possibly switch to a special mode.
-	     (org-element--next-mode type t)
-	     (and (memq type '(item plain-list))
-		  (org-element-property :structure element))
-	     granularity visible-only element))
-	   ;; ELEMENT has contents.  Parse objects inside, if
-	   ;; GRANULARITY allows it.
-	   ((memq granularity '(object nil))
-	    (org-element--parse-objects
-	     cbeg (org-element-property :contents-end element) element
-	     (org-element-restriction type))))
-	  (push (org-element-put-property element :parent acc) elements)
-	  ;; Update mode.
-	  (setq mode (org-element--next-mode type nil))))
+	;; Visible only: skip invisible parts due to folding.
+	(if (and visible-only (org-invisible-p nil t))
+	    (progn
+	      (goto-char (org-find-visible))
+	      (when (and (eolp) (not (eobp))) (forward-char)))
+	  ;; Find current element's type and parse it accordingly to
+	  ;; its category.
+	  (let* ((element (org-element--current-element
+			   end granularity mode structure))
+		 (type (org-element-type element))
+		 (cbeg (org-element-property :contents-begin element)))
+	    (goto-char (org-element-property :end element))
+	    ;; Fill ELEMENT contents by side-effect.
+	    (cond
+	     ;; If element has no contents, don't modify it.
+	     ((not cbeg))
+	     ;; Greater element: parse it between `contents-begin' and
+	     ;; `contents-end'.  Ensure GRANULARITY allows recursion,
+	     ;; or ELEMENT is a headline, in which case going inside
+	     ;; is mandatory, in order to get sub-level headings.
+	     ((and (memq type org-element-greater-elements)
+		   (or (memq granularity '(element object nil))
+		       (and (eq granularity 'greater-element)
+			    (eq type 'section))
+		       (eq type 'headline)))
+	      (org-element--parse-elements
+	       cbeg (org-element-property :contents-end element)
+	       ;; Possibly switch to a special mode.
+	       (org-element--next-mode type t)
+	       (and (memq type '(item plain-list))
+		    (org-element-property :structure element))
+	       granularity visible-only element))
+	     ;; ELEMENT has contents.  Parse objects inside, if
+	     ;; GRANULARITY allows it.
+	     ((memq granularity '(object nil))
+	      (org-element--parse-objects
+	       cbeg (org-element-property :contents-end element) element
+	       (org-element-restriction type))))
+	    (push (org-element-put-property element :parent acc) elements)
+	    ;; Update mode.
+	    (setq mode (org-element--next-mode type nil)))))
       ;; Return result.
       (apply #'org-element-set-contents acc (nreverse elements)))))
 

lisp/org-macs.el

@@ -1065,10 +1065,16 @@ the value in cdr."
       (get-text-property (or (next-single-property-change 0 prop s) 0)
 			 prop s)))
 
-(defun org-invisible-p (&optional pos)
+(defun org-invisible-p (&optional pos folding-only)
   "Non-nil if the character after POS is invisible.
-If POS is nil, use `point' instead."
-  (get-char-property (or pos (point)) 'invisible))
+If POS is nil, use `point' instead.  When optional argument
+FOLDING-ONLY is non-nil, only consider invisible parts due to
+folding of a headline, a block or a drawer, i.e., not because of
+fontification."
+  (let ((value (get-char-property (or pos (point)) 'invisible)))
+    (cond ((not value) nil)
+	  (folding-only (memq value '(org-hide-block org-hide-drawer outline)))
+	  (t value))))
 
 (defun org-truely-invisible-p ()
   "Check if point is at a character currently not visible.

testing/lisp/test-org-element.el

@@ -3353,11 +3353,25 @@ Text
   "Test `org-element-parse-buffer' with visible only argument."
   (should
    (equal '("H1" "H3" "H5")
-      (org-test-with-temp-text
-	  "* H1\n** H2\n** H3 :visible:\n** H4\n** H5 :visible:"
-	(org-occur ":visible:")
-	(org-element-map (org-element-parse-buffer nil t) 'headline
-	  (lambda (hl) (org-element-property :raw-value hl)))))))
+	  (org-test-with-temp-text
+	      "* H1\n** H2\n** H3 :visible:\n** H4\n** H5 :visible:"
+	    (org-occur ":visible:")
+	    (org-element-map (org-element-parse-buffer nil t) 'headline
+	      (lambda (hl) (org-element-property :raw-value hl))))))
+  (should
+   (equal "Test"
+	  (let ((contents "Test"))
+	    (org-test-with-temp-text contents
+	      (add-text-properties 0 1 '(invisible t) contents)
+	      (org-element-map (org-element-parse-buffer nil t) 'plain-text
+		#'org-no-properties nil t)))))
+  (should
+   (equal "Test"
+	  (let ((contents "Test"))
+	    (org-test-with-temp-text (concat "- " contents)
+	      (add-text-properties 0 1 '(invisible t) contents)
+	      (org-element-map (org-element-parse-buffer nil t) 'plain-text
+		#'org-no-properties nil t))))))