For the record, this is what I've recommended and what I will use:

  (defun my/XXX-mode-hook ()
    (when (or buffer-file-name
              (not (string-prefix-p " " (buffer-name))))
      ;; do something expensive
      ))

On Sat, Jan 18, 2025 at 6:36 AM Ihor Radchenko <yantar92@posteo.net> wrote:

> Ship Mints <shipmints@gmail.com> writes:
>
> > Yes, could do, and nothing needed by org-mode or markdown-mode. Could
> also
> > test for buffer-file-name nil. Or test both. Let's recommend that simpler
> > approach and I will rescind my markdown PR in favor of this simpler
> > suggestion.
>
> Well. Org or markdown should name the buffers according to the
> convention :) Org does it though. So, we should be good.
>
> Closing the patch request.
> Canceled.
>
> --
> Ihor Radchenko // yantar92,
> Org mode maintainer,
> Learn more about Org mode at <https://orgmode.org/>.
> Support Org development at <https://liberapay.com/org-mode>,
> or support my work at <https://liberapay.com/yantar92>
>