Steal everything from ox-extra in org-contrib

README.org

@@ -824,14 +824,54 @@ Stolen from [[https://git.sr.ht/~bzg/org-contrib/tree/master/item/lisp/ox-extra.
 
 #+begin_src emacs-lisp
   (with-eval-after-load 'ox
-    (defun my-org-export-ignore-headline-filter (_)
-      "Ignore all headlines with the \":ignore:\" tag."
-      (org-map-entries
-       (lambda ()
-         (delete-region (point) (line-beginning-position 2)))
-       ":ignore:"))
+    (defun org-export-ignore-headlines (data backend info)
+      "Remove headlines tagged \"ignore\" retaining contents and promoting children.
+  Each headline tagged \"ignore\" will be removed retaining its
+  contents and promoting any children headlines to the level of the
+  parent."
+      (org-element-map data 'headline
+        (lambda (object)
+          (when (member "ignore" (org-element-property :tags object))
+            (let ((level-top (org-element-property :level object))
+                  level-diff)
+              (mapc (lambda (el)
+                      ;; recursively promote all nested headlines
+                      (org-element-map el 'headline
+                        (lambda (el)
+                          (when (equal 'headline (org-element-type el))
+                            (unless level-diff
+                              (setq level-diff (- (org-element-property :level el)
+                                                  level-top)))
+                            (org-element-put-property
+                             el :level (- (org-element-property :level el)
+                                          level-diff)))))
+                      ;; insert back into parse tree
+                      (org-element-insert-before el object))
+                    (org-element-contents object)))
+            (org-element-extract-element object)))
+        info nil)
+      (org-extra--merge-sections data backend info)
+      data)
 
-    (defun my-org-latex-header-blocks-filter (backend)
+    (defun org-extra--merge-sections (data _backend info)
+      (org-element-map data 'headline
+        (lambda (hl)
+          (let ((sections
+                 (cl-loop
+                  for el in (org-element-map (org-element-contents hl)
+                                '(headline section) #'identity info)
+                  until (eq (org-element-type el) 'headline)
+                  collect el)))
+            (when (and sections
+                       (> (length sections) 1))
+              (apply #'org-element-adopt-elements
+                     (car sections)
+                     (cl-mapcan (lambda (s) (org-element-contents s))
+                                (cdr sections)))
+              (mapc #'org-element-extract-element (cdr sections)))))
+        info))
+
+    (defun org-latex-header-blocks-filter (backend)
       "Convert marked LaTeX export blocks to \"#+latex_header: \" lines.
   The marker is a line \"#+header: :header yes\" preceding the block.
 
@@ -874,10 +914,12 @@ Stolen from [[https://git.sr.ht/~bzg/org-contrib/tree/master/item/lisp/ox-extra.
     (defun my-activate-buffer-local-org-export-filters ()
       "Activate my export filters locally in the current buffer."
       (interactive)
-      (add-hook 'org-export-before-parsing-hook
-                #'my-org-export-ignore-headline-filter nil 'local)
-      (add-hook 'org-export-before-parsing-hook
-                #'my-org-latex-header-blocks-filter nil 'local)))
+      (set (make-local-variable 'org-export-filter-parse-tree-functions)
+           (cl-pushnew #'org-export-ignore-headlines
+                       org-export-filter-parse-tree-functions))
+      (set (make-local-variable 'org-export-before-parsing-hook)
+           (cl-pushnew #'org-latex-header-blocks-filter
+                       org-export-before-parsing-hook))))
 #+end_src
 
 #+name: emacs-lisp-setup