From: Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: "Gerd Möllmann" <gerd.moellmann@gmail.com>
Cc: 65209@debbugs.gnu.org
Subject: bug#65209: 30.0.50; Unexpected behaviour of setq-local
Date: Sun, 13 Aug 2023 12:43:32 -0400 [thread overview]
Message-ID: <jwvwmxyq4ik.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <953357c8-83b4-5d7f-7638-e79382ad164c@gmail.com> ("Gerd Möllmann"'s message of "Thu, 10 Aug 2023 15:50:26 +0200")
> Evaluate the following
>
> (progn
> (defvar my-var :default-value)
> (make-variable-buffer-local 'my-var)
> (let ((my-var :let-value))
> (setq-local my-var :buffer-local-new))
> my-var)
> => :default-value
>
> (progn
> (defvar my-var1 :default-value)
> (make-variable-buffer-local 'my-var1)
> (setq my-var1 :buffer-local)
> (let ((my-var1 :let-value))
> (setq-local my-var1 :buffer-local-new))
> my-var1)
> => :buffer-local
>
> In both cases, setq-local has no effect.
Hmm... this is a bug in `make-local-variable` where we do:
if (blv ? blv->local_if_set
: (forwarded && BUFFER_OBJFWDP (valcontents.fwd)))
{
tem = Fboundp (variable);
/* Make sure the symbol has a local value in this particular buffer,
by setting it to the same value it already has. */
Fset (variable, (EQ (tem, Qt) ? Fsymbol_value (variable) : Qunbound));
return variable;
}
I.e. we assume that if a var is `make-variable-buffer-local` then `set`
will make sure it has a buffer-local value, but this is not true if the
var is currently let-bound.
40 years after buffer-local and let-bindings were brought together and
we're still finding bugs :-(
Stefan
next prev parent reply other threads:[~2023-08-13 16:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-10 13:50 bug#65209: 30.0.50; Unexpected behaviour of setq-local Gerd Möllmann
2023-08-10 14:00 ` Eli Zaretskii
2023-08-11 0:17 ` Michael Heerdegen
2023-08-11 4:56 ` Gerd Möllmann
2023-08-11 5:53 ` Michael Heerdegen
2023-08-11 8:17 ` Gerd Möllmann
2023-08-11 11:09 ` Eli Zaretskii
2023-08-11 11:34 ` Gerd Möllmann
2023-08-11 11:36 ` Eli Zaretskii
2023-08-13 4:16 ` Michael Heerdegen
2023-08-13 5:53 ` Eli Zaretskii
2023-08-11 14:58 ` Drew Adams
2023-08-13 16:43 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2023-08-13 19:51 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-14 3:24 ` Michael Heerdegen
2023-08-14 4:05 ` Gerd Möllmann
2023-08-18 23:24 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-20 4:43 ` Michael Heerdegen
2023-08-20 6:49 ` Eli Zaretskii
2023-08-22 3:09 ` Michael Heerdegen
2023-08-22 10:56 ` Eli Zaretskii
2023-08-23 3:47 ` Michael Heerdegen
2023-08-23 11:39 ` Eli Zaretskii
2023-08-23 12:51 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-24 1:06 ` Michael Heerdegen
2023-08-24 5:22 ` Eli Zaretskii
2023-08-26 2:09 ` Michael Heerdegen
2023-08-26 6:02 ` Eli Zaretskii
2023-08-26 14:25 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-08-27 4:19 ` Michael Heerdegen
2023-08-24 3:31 ` Michael Heerdegen
2023-08-24 5:35 ` Eli Zaretskii
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