bug#45333: complex command history should not save optional nil parameters

[Michael Heerdegen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> > everything depends on how you define "signature" and where get it from.
> > Does adding an :around advice change the signature of a command?
>
> This isn't a language design issue.  We're talking about making the
> history prettier where it's 100% safe to do so, and nothing more than
> that.

My question is if 100% safe cases exist?  For example:

#+begin_src emacs-lisp
(defun test (&optional x)
  (interactive)
  x)

(advice-add 'test :around (defun test-ad (f &rest args) args))
#+end_src

the signature of `test' is still `(test &optional X)` as reported by C-h
f although the function is able to distinguish a specified nil from a
not specified optional argument.

What you suggest might still be doable by obtaining the effective
signature differently... but I still don't like the idea.

Michael.