bug#64757: 30.0.50; Declare `defadvice` obsolete

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> ...this is too terse.  We need to mention the two alternatives to
> defadvice, including pointers to the ELisp manual's nodes.  People who
> still use defadvice will need those to convert their programs.

Something like that?


        Stefan


diff --git a/etc/NEWS b/etc/NEWS
index c50f560282a..d22969444db 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -610,6 +610,10 @@ provokes an error if used numerically.
 \f
 * Lisp Changes in Emacs 30.1
 
+** 'defadvice' is marked as obsolete.
+See (info "(elisp)Porting Old Advice") for help converting them
+to use `advice-add` or `define-advice instead.
+
 +++
 ** New user option 'safe-local-variable-directories'.
 This user option names directories in which Emacs will treat all
diff --git a/lisp/emacs-lisp/advice.el b/lisp/emacs-lisp/advice.el
index 56f0ae2212c..3265809f592 100644
--- a/lisp/emacs-lisp/advice.el
+++ b/lisp/emacs-lisp/advice.el
@@ -3131,6 +3131,7 @@ defadvice
           [DOCSTRING] [INTERACTIVE-FORM]
           BODY...)"
   (declare (doc-string 3) (indent 2)
+           (obsolete "use advice-add or define-advice" "30.1")
            (debug (&define name  ;; thing being advised.
                            (name ;; class is [&or "before" "around" "after"
                                  ;;               "activation" "deactivation"]