Re: [PATCH] ob-tangle.el: fix ‘:comments noweb’ double linking

[Hraban Luyat <hraban@0brg.net>]

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On 8/3/22 11:55 AM, Max Nikulin wrote:
>> +      (when bare
>> +        (if (and org-babel-tangle-use-relative-file-links
>> +                 (string-match org-link-types-re bare)
>> +                 (string= (match-string 1 bare) "file"))
>> +            (concat "file:"
>> +                    (file-relative-name (substring bare (match-end 0))
>> +                                        (file-name-directory
>> +                                         (cdr (assq :tangle params)))))
>
> Is there any problem with the following?
>
>        (alist-get :tangle params)

This bit of code was moved, I didn't write it. The original code uses a
variable `src-tfile' which isn't available here, so I reused the
definition of that variable (which is (cdr (assq yada yada))). When
creating this patch, I tried to change as little as possible, to keep
everything the same as much as I can. Don't write new code, just move
existing code around.

The (cdr (assq ..)) is used in some other places, too; maybe it's worth
a separate refactor if we want to change that? I'd rather keep this
patch as isolated as possible.

>> +          bare)))))
>
> I have not read the patch care carefully, so I may miss something. It
> seems that (when bare (if (and other...) (action) bare)) may be
> simplified to
>
>       (and bare other... (action))
>
>

Do you mean to rewrite

     (when bare (if x y bare))

to this?

     (and bare x y)

If that's what you meant, I think it would evaluate differently if bare
= truthy and x = falsy, right? Form 1 evaluates to `bare', form 2
evaluates to x (i.e. NIL). Or did I misunderstand the suggestion?

@Ihor: I have rebased the patch and attached it.

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From 778558a5b0d38ee79d47b0068f68c761326e5e61 Mon Sep 17 00:00:00 2001
From: Hraban Luyat <hraban@0brg.net>
Date: Thu, 28 Jul 2022 22:32:08 -0400
Subject: [PATCH] =?UTF-8?q?ob-tangle.el:=20fix=20=E2=80=98:comments=20nowe?=
 =?UTF-8?q?b=E2=80=99=20double=20linking?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* lisp/ob-tangle.el: Refactor the double implementation to a single
helper function.  This avoids the double link wrapping.

* testing/lisp/test-ob-tangle.el: Add unit tests.

Babel tangle allows inserting comments at the tangled site which link
back to the source in the org file.  This linking was implemented
twice, to handle separate cases, but when using ‘:comments noweb’ it
ended up going through both codepaths.  This resulted in doubly
wrapped links.

By refactoring all link generation into a single function, this double
wrapping is avoided.

Example file, /tmp/test.org:

    * Inner
    #+name: inner
    #+begin_src emacs-lisp
    2
    #+end_src

    * Main
    #+header: :tangle test.el :comments noweb :noweb yes
    #+begin_src emacs-lisp
    1
    <<inner>>
    #+end_src

Before:

    ;; [[file:test.org::*Main][Main:1]]
    1
    ;; [[[[file:/tmp/test.org::inner][inner]]][inner]]
    2
    ;; inner ends here
    ;; Main:1 ends here

After:

    ;; [[file:test.org::*Main][Main:1]]
    1
    ;; [[file:test.org::inner][inner]]
    2
    ;; inner ends here
    ;; Main:1 ends here
---
 lisp/ob-tangle.el              | 54 ++++++++++++++++----------------
 testing/lisp/test-ob-tangle.el | 56 ++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 27 deletions(-)

diff --git a/lisp/ob-tangle.el b/lisp/ob-tangle.el
index fdba72278..f85f07e70 100644
--- a/lisp/ob-tangle.el
+++ b/lisp/ob-tangle.el
@@ -469,6 +469,29 @@ code blocks by target file."
     (mapcar (lambda (b) (cons (car b) (nreverse (cdr b))))
 	    (nreverse blocks))))
 
+(defun org-babel-tangle--unbracketed-link (params)
+  "Get a raw link to the src block at point, without brackets.
+
+The PARAMS are the 3rd element of the info for the same src block."
+  (save-match-data
+    (let* (;; The created link is transient.  Using ID is not necessary,
+           ;; but could have side-effects if used.  An ID property may
+           ;; be added to existing entries thus creating unexpected file
+           ;; modifications.
+           (org-id-link-to-org-use-id nil)
+           (l (org-no-properties (org-store-link nil)))
+           (bare (and (string-match org-link-bracket-re l)
+                      (match-string 1 l))))
+      (when bare
+        (if (and org-babel-tangle-use-relative-file-links
+                 (string-match org-link-types-re bare)
+                 (string= (match-string 1 bare) "file"))
+            (concat "file:"
+                    (file-relative-name (substring bare (match-end 0))
+                                        (file-name-directory
+                                         (cdr (assq :tangle params)))))
+          bare)))))
+
 (defun org-babel-tangle-single-block (block-counter &optional only-this-block)
   "Collect the tangled source for current block.
 Return the list of block attributes needed by
@@ -485,16 +508,7 @@ non-nil, return the full association list to be used by
 	 (extra (nth 3 info))
          (coderef (nth 6 info))
 	 (cref-regexp (org-src-coderef-regexp coderef))
-	 (link (let* (
-                      ;; The created link is transient.  Using ID is
-                      ;; not necessary, but could have side-effects if
-                      ;; used.  An ID property may be added to
-                      ;; existing entries thus creatin unexpected file
-                      ;; modifications.
-                      (org-id-link-to-org-use-id nil)
-                      (l (org-no-properties (org-store-link nil))))
-                 (and (string-match org-link-bracket-re l)
-                      (match-string 1 l))))
+	 (link (org-babel-tangle--unbracketed-link params))
 	 (source-name
 	  (or (nth 4 info)
 	      (format "%s:%d"
@@ -548,15 +562,7 @@ non-nil, return the full association list to be used by
 		(if org-babel-tangle-use-relative-file-links
 		    (file-relative-name file)
 		  file)
-		(if (and org-babel-tangle-use-relative-file-links
-			 (string-match org-link-types-re link)
-			 (string= (match-string 1 link) "file")
-                         (stringp src-tfile))
-		    (concat "file:"
-			    (file-relative-name (substring link (match-end 0))
-						(file-name-directory
-						 src-tfile)))
-		  link)
+		link
 		source-name
 		params
 		(if org-src-preserve-indentation
@@ -574,18 +580,12 @@ non-nil, return the full association list to be used by
 INFO, when non nil, is the source block information, as returned
 by `org-babel-get-src-block-info'."
   (let ((link-data (pcase (or info (org-babel-get-src-block-info 'light))
-		     (`(,_ ,_ ,_ ,_ ,name ,start ,_)
+		     (`(,_ ,_ ,params ,_ ,name ,start ,_)
 		      `(("start-line" . ,(org-with-point-at start
 					   (number-to-string
 					    (line-number-at-pos))))
 			("file" . ,(buffer-file-name))
-			("link" . ,(let (;; The created link is transient.  Using ID is
-                                         ;; not necessary, but could have side-effects if
-                                         ;; used.  An ID property may be added to
-                                         ;; existing entries thus creatin unexpected file
-                                         ;; modifications.
-                                         (org-id-link-to-org-use-id nil))
-                                     (org-no-properties (org-store-link nil))))
+			("link" . ,(org-babel-tangle--unbracketed-link params))
 			("source-name" . ,name))))))
     (list (org-fill-template org-babel-tangle-comment-format-beg link-data)
 	  (org-fill-template org-babel-tangle-comment-format-end link-data))))
diff --git a/testing/lisp/test-ob-tangle.el b/testing/lisp/test-ob-tangle.el
index 2ed4ba0da..618e118e0 100644
--- a/testing/lisp/test-ob-tangle.el
+++ b/testing/lisp/test-ob-tangle.el
@@ -159,6 +159,62 @@ echo 1
 	     (search-forward (concat "[file:" file) nil t)))
        (delete-file "test-ob-tangle.el")))))
 
+(ert-deftest ob-tangle/comment-noweb-relative ()
+  "Test :comments noweb tangling with relative file paths."
+  (should
+   (org-test-with-temp-text-in-file
+       "* Inner
+#+name: inner
+#+begin_src emacs-lisp
+2
+#+end_src
+
+* Main
+#+header: :tangle \"test-ob-tangle.el\" :comments noweb :noweb yes
+#+begin_src emacs-lisp
+1
+<<inner>>
+#+end_src"
+     (unwind-protect
+	 (let ((org-babel-tangle-use-relative-file-links t))
+           (org-babel-tangle)
+           (with-temp-buffer
+             (insert-file-contents "test-ob-tangle.el")
+             (buffer-string)
+             (goto-char (point-min))
+             (and
+              (search-forward (concat ";; [[file:" (file-name-nondirectory file) "::inner") nil t)
+              (search-forward ";; inner ends here" nil t))))
+       (delete-file "test-ob-tangle.el")))))
+
+(ert-deftest ob-tangle/comment-noweb-absolute ()
+  "Test :comments noweb tangling with absolute file path."
+  (should
+   (org-test-with-temp-text-in-file
+       "* Inner
+#+name: inner
+#+begin_src emacs-lisp
+2
+#+end_src
+
+* Main
+#+header: :tangle \"test-ob-tangle.el\" :comments noweb :noweb yes
+#+begin_src emacs-lisp
+1
+<<inner>>
+#+end_src"
+     (unwind-protect
+	 (let ((org-babel-tangle-use-relative-file-links nil))
+	   (org-babel-tangle)
+	   (with-temp-buffer
+	     (insert-file-contents "test-ob-tangle.el")
+	     (buffer-string)
+	     (goto-char (point-min))
+             (and
+              (search-forward (concat ";; [[file:" file "::inner") nil t)
+              (search-forward ";; inner ends here" nil t))))
+       (delete-file "test-ob-tangle.el")))))
+
 (ert-deftest ob-tangle/jump-to-org ()
   "Test `org-babel-tangle-jump-to-org' specifications."
   ;; Standard test.
-- 
2.36.1