Re: [PATCH] change dired--find-possibly-alternative-file behaviour.

[Eli Zaretskii <eliz@gnu.org>]

> From: Felix <felix.dick@web.de>
> Cc: emacs-devel@gnu.org
> Date: Sun, 26 Feb 2023 07:32:27 +0100
> 
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Felix <felix.dick@web.de>
> >> Cc: emacs-devel@gnu.org
> >> Date: Sun, 26 Feb 2023 07:07:10 +0100
> >>
> >>
> >> Eli Zaretskii <eliz@gnu.org> writes:
> >>
> >> >> From: Felix <felix.dick@web.de>
> >> >> Date: Sat, 25 Feb 2023 20:43:57 +0100
> >> >>
> >> >> diff --git a/lisp/dired.el b/lisp/dired.el
> >> >> index 76499d0f520..620508bef4f 100644
> >> >> --- a/lisp/dired.el
> >> >> +++ b/lisp/dired.el
> >> >> @@ -2728,7 +2728,8 @@ dired-find-file
> >> >>  (defun dired--find-possibly-alternative-file (file)
> >> >>    "Find FILE, but respect `dired-kill-when-opening-new-dired-buffer'."
> >> >>    (if (and dired-kill-when-opening-new-dired-buffer
> >> >> -           (file-directory-p file))
> >> >> +           (file-directory-p file)
> >> >> +           (= (length (get-buffer-window-list)) 1))
> >> >>        (progn
> >> >>          (set-buffer-modified-p nil)
> >> >>          (dired--find-file #'find-alternate-file file))
> >> >
> >> > What if get-buffer-window-list returns nil?
> >>
> >> The optional argument BUFFER-OR-NAME of get-buffer-window-list defaults
> >> to the current buffer, shouldn't that garantee that it never returns
> >> nil?
> >
> > Only if the current buffer is displayed in some window.
> 
> If get-buffer-window-list returns nil for any case, (length nil) returns 0.
> In that case the if condition is false and dired--find-file will not
> kill any buffer.
> Is there a possible case where the function is called from dired buffer,
> and get-buffer-window-list returns nil?
> In that case the buffer would stay alive!
> 
> dired--find-possibly-alternative-file is only used in 2 places
> dired-find-file and in dired-up-directory.
> I thought those functions are only useful inside dired buffer windows.

I just asked that question to make sure we are not introducing a
regression here.  If you are certain that situation cannot cause any
trouble, I'm okay with that conclusion.