org-babel: Add new "strip-tangle" :noweb argument value

* lisp/ob-tangle.el (org-babel-tangle-single-block): Strip noweb tags
from block if :noweb has been set to "strip-tangle".
* lisp/ob-core.el (org-babel-common-header-args-w-values): Add
"strip-tangle" as new allowed value.
* lisp/ob-core.el (org-babel-noweb-p): Add "strip-tangle" at the
appropriate positions.
* testing/lisp/test-ob-tangle.el (ob-tangle/strip-tangle): Add new test
case for "strip-tangle".
* doc/org-manual.org (Noweb Reference Syntax): Adjust documentation for
the noweb header argument.
* etc/ORG-NEWS: Add entry for new header argument value.

This patch adds the "strip-tangle" option for the :noweb header
argument.  This strips the noweb tags before tangling the block.  This can
be useful for e.g. testing purposes where one wants to use a block as
test case that can be both run inline as well as tangled into a file for
automated testing.

TINYCHANGE

doc/org-manual.org

@@ -18998,6 +18998,12 @@ tangled, or exported.
   Expansion of noweb syntax references in the body of the code block
   when tangling.  No expansion when evaluating or exporting.
 
+- =strip-tangle= ::
+
+  Expansion of noweb syntax references in the body of the code block
+  when evaluating or exporting.  Removes noweb syntax references
+  when exporting.
+
 - =no-export= ::
 
   Expansion of noweb syntax references in the body of the code block

etc/ORG-NEWS

@@ -228,6 +228,11 @@ commands.
 =:noweb-prefix= can be set to =no= to prevent the prefix characters
 from being repeated when expanding a multiline noweb reference.
 
+*** New =:noweb= babel header argument value =strip-tangle=
+
+=:noweb= can be set to =strip-tangle= to strip the noweb syntax references
+before tangling.
+
 *** New LaTeX source block backend using =engraved-faces-latex=
 
 When ~org-latex-src-block-backend~ is set to ~engraved~,

lisp/ob-core.el

@@ -415,7 +415,7 @@ then run `org-babel-switch-to-session'."
     (mkdirp	. ((yes no)))
     (no-expand)
     (noeval)
-    (noweb	. ((yes no tangle no-export strip-export)))
+    (noweb	. ((yes no tangle strip-tangle no-export strip-export)))
     (noweb-ref	. :any)
     (noweb-sep  . :any)
     (noweb-prefix . ((no yes)))
@@ -2885,9 +2885,9 @@ parameters when merging lists."
   "Check if PARAMS require expansion in CONTEXT.
 CONTEXT may be one of :tangle, :export or :eval."
   (let ((allowed-values (cl-case context
-			  (:tangle '("yes" "tangle" "no-export" "strip-export"))
-			  (:eval   '("yes" "no-export" "strip-export" "eval"))
-			  (:export '("yes")))))
+			  (:tangle '("yes" "tangle" "no-export" "strip-export" "strip-tangle"))
+			  (:eval   '("yes" "no-export" "strip-export" "eval" "strip-tangle"))
+			  (:export '("yes" "strip-tangle")))))
     (cl-some (lambda (v) (member v allowed-values))
 	     (split-string (or (cdr (assq :noweb params)) "")))))
 

lisp/ob-tangle.el

@@ -536,7 +536,9 @@ non-nil, return the full association list to be used by
 	 (body
 	  ;; Run the tangle-body-hook.
           (let ((body (if (org-babel-noweb-p params :tangle)
-			  (org-babel-expand-noweb-references info)
+                          (if (string= "strip-tangle" (cdr (assq :noweb (nth 2 info))))
+                            (replace-regexp-in-string (org-babel-noweb-wrap) "" (nth 1 info))
+			    (org-babel-expand-noweb-references info))
 			(nth 1 info))))
 	    (with-temp-buffer
 	      (insert

testing/lisp/test-ob-tangle.el

@@ -510,6 +510,32 @@ another block
 		    (org-split-string (buffer-string))))
 	      (delete-file file))))))
 
+(ert-deftest ob-tangle/strip-tangle ()
+  "Test if strip-tangle works correctly when tangling noweb code blocks."
+  (should
+   (equal '("1")
+          (let ((file (make-temp-file "org-tangle-")))
+            (unwind-protect
+                (progn
+                  (org-test-with-temp-text-in-file
+                   (format "
+#+name: block1
+#+begin_src elisp
+2
+#+end_src
+
+#+begin_src elisp :noweb strip-tangle :tangle %s
+1<<block1>>
+#+end_src
+" file)
+                   (let ((org-babel-noweb-error-all-langs nil)
+                         (org-babel-noweb-error-langs nil))
+                     (org-babel-tangle)))
+                  (with-temp-buffer
+                    (insert-file-contents file)
+                    (org-split-string (buffer-string))))
+              (delete-file file))))))
+
 (ert-deftest ob-tangle/detangle-false-positive ()
   "Test handling of false positive link during detangle."
   (let (buffer)