GNU bug report logs - #7118
24.0.50; dired-subdir-alist, dired-directory, etc.: necessarily buffer-local

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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>
Subject: 24.0.50;
	dired-subdir-alist, dired-directory, etc.: necessarily buffer-local
Date: Mon, 27 Sep 2010 11:47:39 -0700

We should use `make-variable-buffer-local' with vars such as
`dired-subdir-alist' and `dired-directory', instead of just calling
`make-local-variable'.  Why?  Because these vars MUST be buffer local,
and we might as well make the code clearer by pointing that out.  That
is precisely the use case for `make-variable-buffer-local': a var that
is necessarily buffer-local.
 
Also, the doc strings are otherwise incomplete/vague: for
`dired-subdir-alist', for example, it speaks of "the buffer".  The var's
value is local to each particular Dired buffer, and this needs to be
made more clear.  If we use `make-variable-buffer-local' that will add
the necessary info to `C-h v' so that the doc strings begin to make
sense.  (Still, we should mention in the doc string of
`dired-subdir-alist' that the subdirs are subdirs of `dired-directory'.)
 

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2010-09-20 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4) --no-opt --cflags
-Ic:/imagesupport/include'
 

Message #8 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: "Drew Adams" <drew.adams <at> oracle.com>
Cc: 7118 <at> debbugs.gnu.org
Subject: Re: bug#7118: 24.0.50;
	dired-subdir-alist, dired-directory, etc.: necessarily buffer-local
Date: Mon, 27 Sep 2010 23:05:00 +0200

> We should use `make-variable-buffer-local' with vars such as
> `dired-subdir-alist' and `dired-directory', instead of just calling
> `make-local-variable'.

Sounds OK.


        Stefan

Message #11 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Juanma Barranquero <lekktu <at> gmail.com>
To: Drew Adams <drew.adams <at> oracle.com>
Cc: 7118 <at> debbugs.gnu.org
Subject: Re: bug#7118: 24.0.50; dired-subdir-alist, dired-directory, etc.:
	necessarily buffer-local
Date: Tue, 28 Sep 2010 01:35:12 +0200

On Mon, Sep 27, 2010 at 20:47, Drew Adams <drew.adams <at> oracle.com> wrote:

> We should use `make-variable-buffer-local' with vars such as
> `dired-subdir-alist' and `dired-directory', instead of just calling
> `make-local-variable'.  Why?  Because these vars MUST be buffer local,
> and we might as well make the code clearer by pointing that out.  That
> is precisely the use case for `make-variable-buffer-local': a var that
> is necessarily buffer-local.

On the same vein, every single use of revert-buffer-function starts with

  (make-local-variable 'revert-buffer-function)
  (setq revert-buffer-function XXXXX)

or

  (set (make-local-variable 'revert-buffer-function) XXXXXX)

except the one in dired-x.el, which relies in dired-mode doing it
before. There have been at least three bugs in the past year caused by
revert-buffer-function not being automatically buffer-local.

    Juanma

Message #14 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 7118 <at> debbugs.gnu.org, Drew Adams <drew.adams <at> oracle.com>
Subject: Re: bug#7118: 24.0.50;
	dired-subdir-alist, dired-directory, etc.: necessarily buffer-local
Date: Thu, 14 Jul 2011 16:21:32 +0200

Stefan Monnier <monnier <at> iro.umontreal.ca> writes:

>> We should use `make-variable-buffer-local' with vars such as
>> `dired-subdir-alist' and `dired-directory', instead of just calling
>> `make-local-variable'.
>
> Sounds OK.

What's the best way to make this change?  Just say

(make-variable-buffer-local 'var)

after the `defvar', and then removing all the `make-local-variable'
calls?

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

Message #17 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Juanma Barranquero <lekktu <at> gmail.com>
To: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
Cc: 7118 <at> debbugs.gnu.org, Stefan Monnier <monnier <at> iro.umontreal.ca>
Subject: Re: bug#7118: 24.0.50; dired-subdir-alist, dired-directory, etc.:
	necessarily buffer-local
Date: Thu, 14 Jul 2011 16:45:28 +0200

> What's the best way to make this change?  Just say
>
> (make-variable-buffer-local 'var)
>
> after the `defvar', and then removing all the `make-local-variable'
> calls?

Yes.

BTW, it's a mystery to me why `revert-buffer-function' is not
automatically buffer-local, when every single package that sets it
does so locally; having a global non-nil revert-buffer-function does
not make any sense whatsoever.

But IMHO, neither changing `revert-buffer-function' nor
`dired-subdir-alist' and `dired-directory' is really a bug fix. Yes,
as they are now is error prone, but the uses in the sources are
already correct. That should be a wishlist item for 24.2.

    Juanma

Message #20 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
To: Juanma Barranquero <lekktu <at> gmail.com>
Cc: 7118 <at> debbugs.gnu.org, Stefan Monnier <monnier <at> iro.umontreal.ca>
Subject: Re: bug#7118: 24.0.50;
	dired-subdir-alist, dired-directory, etc.: necessarily buffer-local
Date: Thu, 14 Jul 2011 16:49:19 +0200

Juanma Barranquero <lekktu <at> gmail.com> writes:

> But IMHO, neither changing `revert-buffer-function' nor
> `dired-subdir-alist' and `dired-directory' is really a bug fix. Yes,
> as they are now is error prone, but the uses in the sources are
> already correct. That should be a wishlist item for 24.2.

Yeah, that's true.

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

Message #23 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
Cc: Juanma Barranquero <lekktu <at> gmail.com>, 7118 <at> debbugs.gnu.org
Subject: Re: bug#7118: 24.0.50;
	dired-subdir-alist, dired-directory, etc.: necessarily buffer-local
Date: Sat, 16 Jul 2011 22:24:37 -0400

>> But IMHO, neither changing `revert-buffer-function' nor
>> `dired-subdir-alist' and `dired-directory' is really a bug fix.  Yes,
>> as they are now is error prone, but the uses in the sources are
>> already correct. That should be a wishlist item for 24.2.

Indeed.  Also always be extra careful that none of the `setq'
(resulting from removal of make-local-variable) can run before the
make-variable-buffer-local.  This is usually trivially the case, but
problems can appear if the setq is within an autoloaded expression or
when several files are involved.


        Stefan

Message #28 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Drew Adams <drew.adams <at> oracle.com>
To: "'Stefan Monnier'" <monnier <at> iro.umontreal.ca>, "'Lars Magne Ingebrigtsen'"
	<larsi <at> gnus.org>
Cc: 'Juanma Barranquero' <lekktu <at> gmail.com>, 7118 <at> debbugs.gnu.org
Subject: RE: bug#7118: 24.0.50;dired-subdir-alist, dired-directory, etc.:
	necessarily buffer-local
Date: Tue, 2 Aug 2011 14:11:46 -0700 (PDT)

Please don't forget this part of the bug report, which has been ignored so far:

> Still, we should mention in the doc string of
> `dired-subdir-alist' that the subdirs are subdirs of 
> `dired-directory'.

Message #31 received at 7118 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: "Drew Adams" <drew.adams <at> oracle.com>
Cc: 7118 <at> debbugs.gnu.org
Subject: Re: bug#7118: 24.0.50; dired-subdir-alist, dired-directory, etc.:
 necessarily buffer-local
Date: Mon, 07 Feb 2022 01:31:35 +0100

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

> We should use `make-variable-buffer-local' with vars such as
> `dired-subdir-alist' and `dired-directory', instead of just calling
> `make-local-variable'.

I've now fixed this in Emacs 29.

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

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