[emacs] Add checks to the org-roam backlink export

.doom.d/config.org

@@ -502,6 +502,7 @@ be based on their headings.
            :html-doctype "html5"
            :html-html5-fancy t
            :with-sub-superscript nil
+           :section-numbers nil
            ;; :infojs-opt "path:http://thomasf.github.io/solarized-css/org-info.min.js view:showall"
            :auto-sitemap t
            :sitemap-filename "index.org"
@@ -720,6 +721,7 @@ Load shared code snippets to be used in org documents.
 Adapted from https://org-roam.readthedocs.io/en/master/org_export/.
 #+begin_src emacs-lisp
   (defun my/org-roam--backlinks-list-with-content (file)
+    (when (and (stringp file) (f-file? file))
       (with-temp-buffer
         (cd (f-dirname file))
         (hack-dir-local-variables-non-file-buffer)
@@ -736,11 +738,11 @@ Adapted from https://org-roam.readthedocs.io/en/master/org_export/.
                     (pcase-let ((`(,file-from _ ,props) backlink))
                       (insert (s-trim (s-replace "\n" " " (plist-get props :content))))
                       (insert "\n\n")))))))
-      (buffer-string)))
+        (buffer-string))))
 
   (defun my/org-export-preprocessor (backend)
     (let ((links (my/org-roam--backlinks-list-with-content (buffer-file-name))))
-      (unless (string= links "")
+      (unless (or (not (stringp links)) (string= links ""))
         (save-excursion
           (goto-char (point-max))
           (insert (concat "\n* Backlinks\n") links)))))