[PATCH] ob-tangle.el: Blocks overwrite each other when grouping before tangling

[Evgenii Klimov]

And here's the patch to fix it.

>From 2695d48f265a4100a9fc25c4dd278ab2b4b89ba5 Mon Sep 17 00:00:00 2001
From: Evgenii Klimov <eugene.dev@lipklim.org>
Date: Wed, 12 Jul 2023 19:24:48 +0100
Subject: [PATCH] ob-tangle.el: Avoid relative file names when grouping blocks
 to tangle

* lisp/ob-tangle.el (org-babel-effective-tangled-filename): Avoid
using relative file names that could cause one block to overwrite the
others in `org-babel-tangle-collect-blocks' if they have the same
target file but in different formats.
---
 lisp/ob-tangle.el | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/lisp/ob-tangle.el b/lisp/ob-tangle.el
index 25129616f..4aab453e3 100644
--- a/lisp/ob-tangle.el
+++ b/lisp/ob-tangle.el
@@ -427,17 +427,23 @@ that the appropriate major-mode is set.  SPEC has the 
form:
                org-babel-tangle-comment-format-end link-data)))))
 
 (defun org-babel-effective-tangled-filename (buffer-fn src-lang src-tfile)
-  "Return effective tangled filename of a source-code block.
+  "Return effective tangled absolute filename of a source-code block.
 BUFFER-FN is the name of the buffer, SRC-LANG the language of the
 block and SRC-TFILE is the value of the :tangle header argument,
 as computed by `org-babel-tangle-single-block'."
-  (let ((base-name (cond
-                    ((string= "yes" src-tfile)
-                     ;; Use the buffer name
-                     (file-name-sans-extension buffer-fn))
-                    ((string= "no" src-tfile) nil)
-                    ((> (length src-tfile) 0) src-tfile)))
-        (ext (or (cdr (assoc src-lang org-babel-tangle-lang-exts)) src-lang)))
+  (let* ((fnd (file-name-directory (buffer-file-name
+                                    (get-buffer buffer-fn))))
+         (base-name (cond
+                     ((string= "yes" src-tfile)
+                      ;; Use the buffer name
+                      (file-name-concat fnd
+                                        (file-name-sans-extension buffer-fn)))
+                     ((string= "no" src-tfile) nil)
+                     ((> (length src-tfile) 0)
+                      (if (file-name-directory src-tfile)
+                          src-tfile
+                        (file-name-concat fnd src-tfile)))))
+         (ext (or (cdr (assoc src-lang org-babel-tangle-lang-exts)) src-lang)))
     (when base-name
       ;; decide if we want to add ext to base-name
       (if (and ext (string= "yes" src-tfile))
-- 
2.34.1