bug#60464: 29.0.60; Regression - pcomplete-arg fails with argument 'last

[Stefan Monnier]

>  (defun pcomplete-arg (&optional index offset)
>    (let ((arg
>           (nth (+ (pcase index
>                  ('first 0)
>                  ('last  pcomplete-last)
>                  (_      (- pcomplete-index (or index 0))))
>                (or offset 0))
>                pcomplete-args)))
> -    arg
> +    (if (or (stringp arg)
> +            (eq index 'last))
> +        arg
> +      (propertize
> +       (car (split-string (pcomplete-actual-arg index offset)))
> +       'pcomplete-arg-value arg))))
>
> IOW, instead of unconditionally returning arg, we now sometimes (when arg is
> not already a string and when index is not last) return the textual
> representation of that argument (what the user typed in) with the value of
> arg attached to it.

I don't understand the `last` condition.
Could you explain it (e.g. with a concrete example that breaks if you
don't include it)?


        Stefan