Re: pcomplete filename on unregistered commands

[Carlos Pita]

Doing some debugging reveals that this might be a bug.

In shell.el we have:

  ;; Don't use pcomplete's defaulting mechanism, rely on
  ;; shell-dynamic-complete-functions instead.
  (setq-local pcomplete-default-completion-function #'ignore)

So pcomplete is falling back to the ignore (no-op) function. If you
kill the local binding in the shell buffer, then the default of the
default does complete paths.

And what are those dynamic complete functions that are favored in lieu of
pcomplete's default? I don't know, but next in the completion sequence
we have:

        (defun comint-filename-completion ()
      "Return completion data for filename at point, if any."
      (when (comint--match-partial-filename)
        (comint--complete-file-name-data)))

Here (comint--match-partial-filename) will never be true so, ultimately,
we get no completion at all.

Best regards,
Carlos