Subject: bug#30938: 27.0; `dired-do-create-files' etc.: do NOT always raise error if no files

From: Drew Adams <[email-masked]>
Date: Sun, 25 Mar 2018 09:45:57 -0700 (PDT)

For example, `dired-do-isearch' could be called non-interactively
in a context where it should do nothing (or something else should
be done) if there are no marked files.  Something like this is
better:

(defun dired-do-isearch (&optional interactivep)
  "Search for a string through all marked files using Isearch.
When invoked interactively, raise an error if no files are marked."
  (interactive "p")
  (multi-isearch-files
   (dired-get-marked-files
     nil nil 'dired-nondirectory-p nil interactivep)))