* lisp/emacs-lisp/nadvice.el (advice--tweak): New function.

(advice--remove-function, advice--subst-main): Use it.
* lisp/emacs-lisp/advice.el: Update commentary.

2 files changed, 22 insertions, 25 deletions

diff --git a/lisp/emacs-lisp/advice.el b/lisp/emacs-lisp/advice.el
index d9d8e4f3b02..07340f06a13 100644
--- a/lisp/emacs-lisp/advice.el
+++ b/lisp/emacs-lisp/advice.el
@@ -589,13 +589,11 @@
 ;; Advice implements forward advice mainly via the following: 1) Separation
 ;; of advice definition and activation that makes it possible to accumulate
 ;; advice information without having the original function already defined,
-;; 2) special versions of the built-in functions `fset/defalias' which check
-;; for advice information whenever they define a function.  If advice
-;; information was found then the advice will immediately get activated when
-;; the function gets defined.
+;; 2) Use of the `defalias-fset-function' symbol property which lets
+;; us advise the function when it gets defined.
 
 ;; Automatic advice activation means, that whenever a function gets defined
-;; with either `defun', `defmacro', `fset' or by loading a byte-compiled
+;; with either `defun', `defmacro', `defalias' or by loading a byte-compiled
 ;; file, and the function has some advice-info stored with it then that
 ;; advice will get activated right away.
 
diff --git a/lisp/emacs-lisp/nadvice.el b/lisp/emacs-lisp/nadvice.el
index b4d6fac92a2..1715763d482 100644
--- a/lisp/emacs-lisp/nadvice.el
+++ b/lisp/emacs-lisp/nadvice.el
@@ -167,20 +167,26 @@ WHERE is a symbol to select an entry in `advice--where-alist'."
         (setq definition (advice--cdr definition))))
     found))
 
-;;;###autoload
-(defun advice--remove-function (flist function)
+(defun advice--tweak (flist tweaker)
   (if (not (advice--p flist))
-      flist
+      (funcall tweaker nil flist nil)
     (let ((first (advice--car flist))
+          (rest (advice--cdr flist))
           (props (advice--props flist)))
-      (if (or (equal function first)
-              (equal function (cdr (assq 'name props))))
-          (advice--cdr flist)
-        (let* ((rest (advice--cdr flist))
-               (nrest (advice--remove-function rest function)))
-          (if (eq rest nrest) flist
-            (advice--make-1 (aref flist 1) (aref flist 3)
-                            first nrest props)))))))
+      (or (funcall tweaker first rest props)
+          (let ((nrest (advice--tweak rest tweaker)))
+            (if (eq rest nrest) flist
+              (advice--make-1 (aref flist 1) (aref flist 3)
+                              first nrest props)))))))
+
+;;;###autoload
+(defun advice--remove-function (flist function)
+  (advice--tweak flist
+                 (lambda (first rest props)
+                   (if (or (not first)
+                           (equal function first)
+                           (equal function (cdr (assq 'name props))))
+                       rest))))
 
 (defvar advice--buffer-local-function-sample nil)
 
@@ -269,15 +275,8 @@ of the piece of advice."
 ;;;; Specific application of add-function to `symbol-function' for advice.
 
 (defun advice--subst-main (old new)
-  (if (not (advice--p old))
-      new
-    (let* ((first (advice--car old))
-           (rest (advice--cdr old))
-           (props (advice--props old))
-           (nrest (advice--subst-main rest new)))
-      (if (equal rest nrest) old
-        (advice--make-1 (aref old 1) (aref old 3)
-                        first nrest props)))))
+  (advice--tweak old
+                 (lambda (first _rest _props) (if (not first) new))))
 
 (defun advice--normalize (symbol def)
   (cond