describe-function and advised C functions

[Tassilo Horn <tsdh@gnu.org>]

Hi all,

when advising a C function foo, C-h f foo just says that "foo is an
compiled lisp function" without a link to the source.

With Emacs 23 and 24.3, it said "foo is a built-in function in `C source
code'."  which is much more helpful.

The following patch restores that behavior for the current trunk.  Good
to commit?

--8<---------------cut here---------------start------------->8---
=== modified file 'lisp/help-fns.el'
--- lisp/help-fns.el	2013-06-15 01:12:05 +0000
+++ lisp/help-fns.el	2013-12-03 09:03:21 +0000
@@ -541,9 +541,10 @@
 		     (and (fboundp origname) origname)))
 	      function))
 	 ;; Get the real definition.
-	 (def (if (symbolp real-function)
-		  (symbol-function real-function)
-		function))
+	 (def (cond
+	       (advised (ad-get-orig-definition real-function))
+	       ((symbolp real-function) (symbol-function real-function))
+	       (t function)))
 	 (aliased (symbolp def))
 	 (real-def (if aliased
 		       (let ((f def))
--8<---------------cut here---------------end--------------->8---

Bye,
Tassilo