Right, right. It's not a pattern we can expect people to follow at this
stage of Emacs evolution and popularity.

On Thu, Jan 30, 2025 at 1:47 PM Juri Linkov <juri@linkov.net> wrote:

> close 75945 31.0.50
> thanks
>
> > That trick works, if a bit circuitous. Thank you.
>
> Ok, then let's close this report.
>
> > Is it really the case that adding an &optional argument to a hook
> function
> > breaks those that accept only the mandatory arguments?
>
> The caller needs to provide the optional argument in any case.
> But the user still has only mandatory arguments.
> Therefore the error with wrong number of arguments.
>
> A precautious user could add '&rest args' to the end of ALL own hook
> functions for the case when the callers decide to add more arguments.
> Then for the caller it would be safe to call the hook
> with any number of arguments.
>