bug#9923: 24.0.91; `where-is' does not find recentf menu items (cmds, not files)

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

> Recently clicking the context menu at the end of the buffer raises an error,
> and during the short time period before the problem was noticed and fixed,
> the error in one context menu item broke completion of M-x.
> It might surprise the users why an error in context menus
> affects such unrelated things.  So maybe such patch makes sense
> to prevent M-x completion from breaking?
>
> diff --git a/lisp/simple.el b/lisp/simple.el
> index b0ff4236e1..5581d41356 100644
> --- a/lisp/simple.el
> +++ b/lisp/simple.el
> @@ -2117,7 +2117,9 @@ read-extended-command--affixation
>      (mapcar
>       (lambda (command-name)
>         (let* ((fun (and (stringp command-name) (intern-soft command-name)))
> -              (binding (where-is-internal fun overriding-local-map t))
> +              (binding (unless (eq fun 'ignore)
> +                         ;; Ignore errors in context-menu.
> +                         (where-is-internal fun overriding-local-map t)))

I think adding code specific to context-menu in
`read-extended-command--affixation` is a bad idea.

So maybe we should add an `with-demoted-errors` and just mention
context-menu as an example of the kind of errors we want to disregard.
Or maybe we should investigate why `ignore` causes an error here?


        Stefan