From 0aea302ff0769494620cb958cf3bcc954e1233ee Mon Sep 17 00:00:00 2001
From: Ionut Adrian Ciolan <iadrian@ciolan.net>
Date: Sun, 29 Jun 2025 23:38:10 +0300
Subject: [PATCH] fix errors when trying to add linenumbers outside of a
 src-block

---
 scimax-ob-line-numbers.el | 44 +++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/scimax-ob-line-numbers.el b/scimax-ob-line-numbers.el
index de69697..b016c46 100644
--- a/scimax-ob-line-numbers.el
+++ b/scimax-ob-line-numbers.el
@@ -41,24 +41,36 @@
   (remove-hook 'post-command-hook #'scimax-ob-add-line-numbers t))
 
 (defun scimax-ob-add-line-numbers ()
-  "Add line numbers to the current Org source block."
+  "Add line numbers to an org src-block."
   (interactive)
   (save-excursion
-    (let* ((src-block (org-element-context))
-           (nlines (- (length (s-split "\n" (org-element-property :value src-block))) 1)))
-      (scimax-ob-remove-line-numbers)
-      (goto-char (org-element-property :begin src-block))
-      (while (not (looking-at "#\\+BEGIN"))
-        (forward-line))
-      (forward-line)
-      (cl-loop for i from 1 to nlines do
-               (beginning-of-line)
-               (let ((ov (make-overlay (point) (point))))
-                 (overlay-put ov 'before-string
-                              (propertize (format "%03s " i)
-                                          'font-lock-face '(:foreground "fg-main" :background "bg-main")))
-                 (push ov scimax-ob-number-line-overlays))
-               (forward-line))))
+    (let* ((src-block (org-element-context)))
+      (when (eq (org-element-type src-block) 'src-block)
+      ;;iAdrian patch - fix 'wrong-type-argument stringp nil' coming from the 'org-element-property :value src-block => nil' when trying to add linenumbers outside of a src-block (see commented code below which is the original version)
+       (let* ((value (org-element-property :value src-block))
+               (nlines (if value (1- (length (s-split "\n" value))) 0)))
+;;        (let* ((src-block (org-element-context))
+;;           (nlines (- (length (s-split "\n" (org-element-property :value src-block))) 1)))
+          ;; clear any existing overlays
+          (scimax-ob-remove-line-numbers)
+
+          (goto-char (org-element-property :begin src-block))
+          ;; the beginning may be header, so we move forward to get the #+BEGIN
+          ;; line. Then jump one more to get in the code block
+          (while (not (looking-at "#\\+BEGIN"))
+            (forward-line))
+          (forward-line)
+          (cl-loop for i from 1 to nlines
+                   do
+                   (beginning-of-line)
+                   (let ((ov (make-overlay (point) (point))))
+                     (overlay-put
+                      ov
+                      'before-string (propertize
+                                      (format "%03s " (number-to-string i))
+                                      'font-lock-face '(:foreground "fg-main" :background "bg-main")))
+                     (push ov scimax-ob-number-line-overlays))
+                   (forward-line))))))
   (add-hook 'post-command-hook #'scimax-ob-add-line-numbers nil 'local))
 
 (provide 'scimax-ob-line-numbers)