[PATCH] ox-texinfo: Support links in headings

["Rudolf Adamkovič" <rudolf@adamkovic.org>]

From: Rudolf Adamkovic <rudolf@adamkovic.org>

* etc/ORG-NEWS (Texinfo exporter now supports links in headings):
Announce the new feature.
* lisp/ox-texinfo.el: (org-texinfo--format-entries,
org-texinfo--get-node, org-texinfo--sanitize-title-reference,
org-texinfo--sanitize-title): A 2-step change: (1) Rename
`--sanitize-title' to `--sanitize-title-reference' and (2) create a
new `--sanitize-title' sanitation function.  The new function is less
strict in that does not remove links, which should be allowed in
sectioning commands, such as `@unnumbered'.  The old function remains
more strict, which is useful for generating `@node' names, for
example.
* testing/lisp/test-ox-texinfo.el:
(test-ox-texinfo/headings-with-links): Test the new functionality to
avoid regressions in the future.
---
 etc/ORG-NEWS                    |  6 ++++++
 lisp/ox-texinfo.el              | 17 +++++++++++++++--
 testing/lisp/test-ox-texinfo.el | 28 ++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index 392788055..a9357aa28 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -223,6 +223,12 @@ This way, attachments will remain accessible when opening symlinked Org file.
 When no attach dir exists, Org mode will still prefer creating it in
 the "default" directory - where the symlink is located.
 
+*** Texinfo exporter now supports links in headings
+
+The Texinfo exporter no longer removes links from headings.  This
+applies to all headings, below and above the =H= and =toc= export
+=#+OPTIONS:=.
+
 * Version 9.7
 
 ** Important announcements and breaking changes
diff --git a/lisp/ox-texinfo.el b/lisp/ox-texinfo.el
index 6adee9fca..d710b892d 100644
--- a/lisp/ox-texinfo.el
+++ b/lisp/ox-texinfo.el
@@ -524,7 +524,7 @@ node or anchor name is unique."
 		(org-texinfo--sanitize-node
 		 (pcase (org-element-type datum)
 		   (`headline
-		    (org-texinfo--sanitize-title
+		    (org-texinfo--sanitize-title-reference
 		     (org-export-get-alt-title datum info) info))
 		   (`radio-target
 		    (org-export-data (org-element-contents datum) info))
@@ -569,6 +569,19 @@ periods, commas and colons."
 (defun org-texinfo--sanitize-title (title info)
   "Make TITLE suitable as a section name.
 TITLE is a string or a secondary string.  INFO is the current
+export state, as a plist."
+  (org-export-data-with-backend
+   title
+   (org-export-create-backend
+    :parent 'texinfo
+    :transcoders `((footnote-reference . ,#'ignore)
+                   (radio-target . ,(lambda (_r c _) c))
+                   (target . ,#'ignore)))
+   info))
+
+(defun org-texinfo--sanitize-title-reference (title info)
+  "Make TITLE suitable as a section reference.
+TITLE is a string or a secondary string.  INFO is the current
 export state, as a plist."
   (org-export-data-with-backend
    title (org-export-toc-entry-backend 'texinfo) info))
@@ -1468,7 +1481,7 @@ a plist containing contextual information."
 	      ;; name.  Remove them.
 	      (replace-regexp-in-string
 	       "[ \t]*:+" ""
-	       (org-texinfo--sanitize-title
+	       (org-texinfo--sanitize-title-reference
 		(org-export-get-alt-title h info) info)))
 	     (node (org-texinfo--get-node h info))
 	     (entry (concat "* " title ":"
diff --git a/testing/lisp/test-ox-texinfo.el b/testing/lisp/test-ox-texinfo.el
index b16a344e7..917c7f1cd 100644
--- a/testing/lisp/test-ox-texinfo.el
+++ b/testing/lisp/test-ox-texinfo.el
@@ -345,5 +345,33 @@ body
        (should-not (org-element-contents section))
        (should (eq first-heading (org-element-parent section)))))))
 
+\f
+;;; Headings with links
+
+(ert-deftest test-ox-texinfo/headings-with-links ()
+  "Test node and chapter names."
+  (should
+   (org-test-with-temp-text
+       (string-join
+        (list "* Heading 1"
+              "  ...."
+              "* Heading 2 ([[* Heading 1][Heading 1]])"
+              "  ....")
+        "\n")
+     (let ((export-buffer "*Test Texinfo Export*")
+           (org-export-show-temporary-export-buffer nil))
+       (org-export-to-buffer 'texinfo export-buffer
+         nil nil nil nil nil
+         #'texinfo-mode)
+       (with-current-buffer export-buffer
+         (goto-char (point-min))
+         (and
+          (re-search-forward "^* Heading 1::$")
+          (re-search-forward "^* Heading 2 (Heading 1)::$")
+          (re-search-forward "^@node Heading 1$")
+          (re-search-forward "^@chapter Heading 1$")
+          (re-search-forward "^@node Heading 2 (Heading 1)$")
+          (re-search-forward "^@chapter Heading 2 (@ref{Heading 1})$")))))))
+
 (provide 'test-ox-texinfo)
 ;;; test-ox-texinfo.el end here
-- 
2.46.0