GNU bug report logs - #52395
27.2; Expansion of DIR arg of `dired-buffers-for-dir'

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 52395 in the body.
You can then email your comments to 52395 AT debbugs.gnu.org in the normal way.

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

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

From: Drew Adams <drew.adams <at> oracle.com>
To: "bug-gnu-emacs <at> gnu.org" <bug-gnu-emacs <at> gnu.org>
Subject: 27.2; Expansion of DIR arg of `dired-buffers-for-dir'
Date: Thu, 9 Dec 2021 21:59:46 +0000

This bug report is in the form of a question.  Shouldn't this function
expand the DIR argument using `expand-file-name' (e.g. with
`default-directory')?

I think the answer is "yes", but perhaps there's some good reason the
answer should be "no".

All uses of `dired-buffers-for-dir' I'm aware of call `expand-file-name'
on the directory passed as arg.

If you instead pass, say, "~/some/dir/", then a Dired buffer for that
directory won't be found.  To me, that seems like a bug.  The "problem"
is that the code just uses `assoc' to look up the given DIR argument in
the value of `dired-subdir-alist', and entries in that alist have
absolute (i.e., expanded) dir names as their cars.

At the very least, the doc should tell you about the gotcha - it should
tell you to expand the DIR arg before calling.

I'd propose changing the first line of the `dired-buffers-for-dir' code
from this:

  (setq dir  (file-name-as-directory dir))

to this:

  (setq dir  (expand-file-name (file-name-as-directory dir)))

That way, there's no need for callers to themselves expand the dir name.

(A question is whether `file-truename' should be used instead of
`expand-file-name'.  I guess not.)

Such a code change shouldn't change the behavior of any existing code,
since that seems to always use `expand-file-name' before calling
`dired-buffers-for-dir'.

If this code change is made then it would be good to also change the
doc to say that DIR is expanded relative to `default-directoy'.  Code
that needs a name expanded properly relative to some other directory will
then be sure to expand the name before calling `dired-buffers-for-dir'.
___

If you don't agree to such a code change, fine.  But in that case I
suggest that the doc of `dired-buffers-for-dir' say explicitly that
argument DIR needs to be an expanded absolute file name.  The doc needs
to explicitly say "expanded", because `file-absolute-p' doesn't test for
this meaning of "absolute" file name - the name cannot use `~' for a
home directory.

In GNU Emacs 27.2 (build 1, x86_64-w64-mingw32)
 of 2021-03-26 built on CIRROCUMULUS
Repository revision: deef5efafb70f4b171265b896505b92b6eef24e6
Repository branch: HEAD
Windowing system distributor 'Microsoft Corp.', version 10.0.19042
System Description: Microsoft Windows 10 Pro (v10.0.2009.19042.1348)

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static''

Message #10 received at 52395 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Drew Adams <drew.adams <at> oracle.com>
Cc: 52395 <at> debbugs.gnu.org
Subject: Re: bug#52395: 27.2; Expansion of DIR arg of `dired-buffers-for-dir'
Date: Fri, 10 Dec 2021 12:33:20 +0100

Drew Adams <drew.adams <at> oracle.com> writes:

> This bug report is in the form of a question.  Shouldn't this function
> expand the DIR argument using `expand-file-name' (e.g. with
> `default-directory')?

Makes sense to me.  Now done in Emacs 29.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Previous Next

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