GNU bug report logs - #79127
30.1; Inaccurate description of find-file-noselect with NOWARN non-nil

Previous Next

To reply to this bug, email your comments to 79127 AT debbugs.gnu.org.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: richard newton <richardn26 <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 30.1; Inaccurate description of find-file-noselect with NOWARN non-nil
Date: Wed, 30 Jul 2025 13:02:02 +0200

[Message part 1 (text/plain, inline)]

Description of find-file-noselect says "If a buffer exists visiting
FILENAME, return that one, but verify that the file has not changed since
visited or saved."

The description for arg NOWARN only says
"Optional second arg NOWARN non-nil means suppress any warning messages."

But if NOWARN is non-nil then it also does not verify that the file has not
changed

Ideally, the code should be changed to match the description. If not, the
description for NOWARN could be improved.

Simple testcase - with NOWARN, buffer does not get updated with update 2

(defun testcase ()
  (interactive)
  (get-buffer-create "testing")
  (switch-to-buffer "testing")
  (shell-command-to-string (concat "echo start > /tmp/test1"))
  (set-buffer (find-file-noselect "/tmp/test1"))
  (switch-to-buffer "testing")
  (shell-command-to-string (concat "echo update 1 > /tmp/test1"))
  ;; without NOWARN - will prompt to update file
  (set-buffer (find-file-noselect "/tmp/test1"))
  (goto-char (point-min))
  (let ((beg (point)))
    (goto-char (point-max))
    (message (buffer-substring-no-properties beg (point))))
  (shell-command-to-string (concat "echo update 2 > /tmp/test1"))
  ;; with NOWARN
  (set-buffer (find-file-noselect "/tmp/test1" t))
  (goto-char (point-min))
  (let ((beg (point)))
    (goto-char (point-max))
    (message (buffer-substring-no-properties beg (point)))))

[Message part 2 (text/html, inline)]

Message #8 received at 79127 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: richard newton <richardn26 <at> gmail.com>
Cc: 79127 <at> debbugs.gnu.org
Subject: Re: bug#79127: 30.1;
 Inaccurate description of find-file-noselect with NOWARN non-nil
Date: Sat, 02 Aug 2025 17:35:36 +0300

> From: richard newton <richardn26 <at> gmail.com>
> Date: Wed, 30 Jul 2025 13:02:02 +0200
> 
> Description of find-file-noselect says "If a buffer exists visiting FILENAME, return that one, but verify that the
> file has not changed since visited or saved."
> 
> The description for arg NOWARN only says
> "Optional second arg NOWARN non-nil means suppress any warning messages."
> 
> But if NOWARN is non-nil then it also does not verify that the file has not changed
> 
> Ideally, the code should be changed to match the description. If not, the description for NOWARN could be
> improved.

Thanks.  I opted to change the documentation (on the emacs-30 branch),
since NOWARN should not be used when there's a possibility that the
file has been edited behind Emacs's back, and it's impossible to not
warn if we discover that it has been.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.